Battery module and assembling method for the same

Abstract

To provide a battery module with a reduced number of parts and capable of reducing the volume occupied by components other than battery cells to improve the energy efficiency of the battery.SOLUTION: A battery module 200 has the following configuration. One end side member of a restraining member 90 is a frame member for restraining a plurality of battery cells 70 stacked in the horizontal direction from the upper side thereof. The other end side member is a frame member for restraining the plurality of battery cells 70 stacked in the horizontal direction from the lower side thereof. The one end side member and the other end side member are bonded to each other at the outer circumferential portion of the stacked plurality of battery cells. The restraining member 90 restrains the stacked plurality of battery cells 70 in the stacking direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery module and a method for assembling a battery module. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there have been known storage modules and the like that are configured by stacking a plurality of battery cells (see Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-055487 A [Patent Document 2] Patent Publication No. 2021-009786 [Patent Document 3] JP 2022-055798 A [Patent Document 4] JP 2023-060672 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned power storage modules and the like, the restraining members that restrain the multiple battery cells are numerous, and there has been a demand for a reduced number of parts and for a reduced volume occupied by incidental parts other than the battery cells.

[0005] An object of the present invention is to provide a battery module that has a reduced number of parts and that can reduce the volume occupied by auxiliary parts other than the battery cells, in order to improve the energy efficiency of the battery. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a battery module (for example, "battery module 200" described below) comprising a plurality of stacked battery cells (e.g., "battery cell 70" described below) and a restraining member (for example, "restraining member 90" described below) that restrains the stacked plurality of battery cells in a stacking direction of the plurality of battery cells, the restraining member being composed of a one end side member (for example, "upper member 92" described below) and an other end side member (for example, "lower member 91" described below) for restraining the plurality of battery cells, the one end side member being a frame member for restraining the plurality of stacked battery cells from an upper side in the horizontal direction, and the other end side member being a frame member for restraining the plurality of stacked battery cells from a lower side in the horizontal direction, the one end side member and the other end side member being joined at the outer periphery of the stacked plurality of battery cells, and the restraining member restraining the stacked plurality of battery cells in the stacking direction.

[0007] In the above invention, it is preferable that the stacked battery cells are in a pressurized state. Also, it is preferable that the one-end member and the other-end member are joined to side portions of the outer periphery of the stacked battery cells. It is preferable that the other-end member is located outside the one-end member and joined to the one-end member.

[0008] It is also preferable that the one-end side member and the other-end side member are joined by fitting or bonding. It is preferable that the one-end side member is configured to cover upper ends of the plurality of battery cells stacked in the horizontal direction and is open to upper surfaces of the plurality of battery cells stacked in the horizontal direction, and the other-end side member is configured to cover lower ends of the plurality of battery cells stacked in the horizontal direction and is open to lower surfaces of the plurality of battery cells stacked in the horizontal direction.

[0009] Furthermore, it is preferable that the end in the stacking direction of the restraining member that restrains the stacked battery cells is open. The other end member is configured to cover the horizontally stacked battery cells from their lower ends to their side faces, and it is preferable that the upper end of the other end member is located above the upper surface of the one end member. It is preferable that the upper end of the other end member has a protrusion (for example, "protrusion 916" described below) located above the upper surface of the one end member.

[0010] The present invention also relates to an assembly method for assembling a restraining member (e.g., the "restraining member 90" described below) consisting of a one-end side member (e.g., the "upper member 92" described below) and an other-end side member (e.g., the "lower member 91" described below) to a plurality of stacked battery cells (e.g., the "battery cells 70" described below), the method including the steps of setting the plurality of battery cells in a stacked state in an assembly jig (e.g., the "assembly jig 500" described below); the one-end side member covering the upper surfaces of the battery cells from the upper surfaces of the battery cells stacked in the horizontal direction under pressure; and joining the one-end side member and the other-end side member assembled above and below the battery cells.

[0011] In the above invention, it is preferable that the lower portion of the assembly jig has a push-up jig (e.g., the "push-up jig 503" described below) including a push pin (e.g., the "push-up pin 504" described below) and a groove portion (e.g., the "groove 5031" described below), and in the step of assembling the other-end side member, the other-end side member is set in the groove portion, and the other-end side member is pushed up by the push-up jig including the push pin to assemble the stacked multiple battery cells into the other-end side member.

[0012] In the step of applying pressure, it is preferable that pressure be applied to the stacked battery cells from one side or both sides in the stacking direction.

[0013] In addition, in the step of incorporating the one-end side member, it is preferable to incorporate the one-end side member from above the stacked battery cells into which the other-end side member has been incorporated on the lower side, or from above the stacked battery cells before the other-end side member has been incorporated on the lower side. In the step of joining the one-end side member and the other-end side member, it is preferable to join the one-end side member and the other-end side member by fitting or welding. It is preferable that the one-end side member and the other-end side member each have an annular shape and form a frame for fixing the plurality of battery cells. It is also preferable that the other-end side member has a gripped portion (for example, the "protrusion 916" described below) that can be gripped when the stacked battery cells to which the restraining member is assembled are stored in a battery module case. Effect of the Invention

[0014] According to the present invention, it is possible to provide a battery module that has a reduced number of parts and that can reduce the volume occupied by auxiliary parts other than the battery cells in order to improve the energy efficiency of the battery. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a battery pack according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing the battery pack in the embodiment. [Diagram 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] 4 is a plan view of an end portion in the stacking direction of a battery stack of the battery pack according to the embodiment. FIG. [Diagram 5] 4 is an enlarged perspective view of an end portion in the stacking direction of a battery stack of the battery pack according to the embodiment. FIG. [Figure 6]4 is an enlarged partial cross-sectional view of an end portion in the stacking direction of a battery stack of the battery pack according to the embodiment. FIG. [Figure 7] FIG. 2 is an exploded perspective view showing the battery pack in the embodiment. [Figure 8] FIG. 2 is a perspective view showing a battery module of the battery pack in the embodiment. [Figure 9] 13A and 13B are diagrams showing how upper and lower members are assembled from above and below the battery stack of the battery module according to the embodiment. [Figure 10] FIG. 2 is a side view showing the battery module in the embodiment. [Figure 11] FIG. 11 is a cross-sectional perspective view taken along line BB in FIG. [Figure 12] FIG. 11 is a cross-sectional perspective view taken along line CC in FIG. [Figure 13] FIG. 2 is an enlarged perspective view showing a battery module in the embodiment. [Figure 14] FIG. 2 is a perspective view showing a state before the battery module is inserted into a case in the embodiment. [Figure 15] 1 is a perspective view showing an assembly jig for incorporating a restraining member into a battery stack of a battery module according to the embodiment. FIG. [Figure 16] 13A and 13B are diagrams illustrating how restraining members are incorporated into a battery stack of a battery module in an assembly jig according to the embodiment. [Figure 17] 11 is a side cross-sectional view showing how a lower member of a restraining member is assembled into a battery stack of a battery module according to the embodiment. FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line DD in FIG. [Figure 19] 13A and 13B are diagrams illustrating how the lower and upper members of the restraining member are assembled into the battery stack in a pressurized state of the battery module according to the embodiment. [Figure 20] 11A and 11B are diagrams illustrating how restraining members are incorporated into the battery stack according to the embodiment. [Figure 21] 5A to 5C are diagrams illustrating a state in which a battery module is inserted into a case in the embodiment. [Figure 22] 4A and 4B are diagrams illustrating a state in which a battery module is inserted into a case in this embodiment. [Diagram 23] 11 is a perspective view showing a state in which a lower member of a restraining member of a battery module is inserted into a groove formed in an upper surface of a push-up jig in the embodiment. FIG. [Figure 24] 13 is a perspective view showing a state in which a battery stack is placed on a lower member of a restraining member for a battery module in this embodiment, the lower member being inserted into a groove formed in the upper surface of a push-up jig. FIG. [Diagram 25] 13 is a perspective view showing a battery stack arranged on a lower member of a restraining member for a battery module according to the embodiment, the restraining member being inserted into a groove formed in the upper surface of a push-up jig. FIG. [Figure 26] 10 is a perspective view showing a state in which pressure is applied from the stacking direction of the battery cells to a battery stack arranged on a lower member of a restraining member of a battery module according to the embodiment. FIG. [Figure 27] 10 is a cross-sectional view showing a state in which pressure is applied from the stacking direction of the battery cells to a battery stack arranged on a lower member of a restraining member of a battery module in the embodiment. FIG. [Figure 28] FIG. 11 is a cross-sectional view showing how the lower member is assembled from below and the upper member is assembled from above in a state in which pressure is applied to a battery stack arranged on the lower member of a restraining member of a battery module in this embodiment from the stacking direction of the battery cells. [Figure 29] FIG. 11 is a cross-sectional view showing the state in which the lower member is assembled from below and the upper member is assembled from above with pressure being applied to a battery stack arranged on a lower member of a restraining member of a battery module in this embodiment from the stacking direction of the battery cells. [Diagram 30] 13 is a cross-sectional view showing the state in which a pressure tool formed by a round bar has been retracted from the battery stack with the lower and upper members of the restraint members of the battery modules in the embodiment assembled into the battery stack. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings, in which: FIG. 1 is a schematic diagram of a battery pack according to an embodiment of the present invention;

[0017] Hereinafter, as shown in Figure 2 etc., two predetermined directions that intersect at right angles in a horizontal plane will be referred to as the "X direction" and the "Y direction". Furthermore, one of the X directions will be referred to as the "X- direction" and the opposite direction will be referred to as the "X+ direction". Furthermore, one of the Y directions will be referred to as the "Y- direction" and the opposite direction will be referred to as the "Y+ direction".

[0018] 1, 2, etc., the case 80 has a box shape that opens upward and houses two battery stacks Bs aligned in the X direction. The case 80 is made of a material such as metal.

[0019] 6, a through hole 801 is formed in the outer surface of the front wall of case 80 (the surface opposite the battery stack Bs side) for inserting a pressure jig 505 (see FIG. 15, etc.) configured as a pressure rod as described below to apply pressure to the battery stack Bs via the end plate 95. A spacer 85 is provided opposite through hole 801 as a pressure member that comes into contact with a relatively thick, convex portion of end plate 95 (described below) to apply pressure to the battery stack Bs.

[0020] A disk-shaped recess 851 recessed toward the battery stack Bs is formed in the spacer 85 at a position facing the through-hole 801. The through-hole 801 is provided with a pressure release valve (not shown).

[0021] 2, each battery stack Bs includes multiple battery cells 70 and multiple separators 79. Each battery stack Bs is restrained by restraining members 90 to form a battery module 200. End plates 95 (see FIG. 3, etc.) are disposed at the ends of the battery module 200 in the stacking direction to form a stacked cell ASSY.

[0022] Each battery cell 70 has a rectangular exterior that is elongated in the Y direction. Therefore, the "Y direction" may be interpreted as the "cell length direction." In each battery stack Bs, the battery cells 70 are stacked in the X direction. Therefore, the "X direction" may be interpreted as the "stacking direction." The separators 79 are plate-shaped members that extend in the Y direction and the up-down direction, and are disposed between every two battery cells 70 that are aligned in the X direction. The separators 79 are made of a material such as resin.

[0023] Plate-shaped spacers 89 extending in the X direction and up and down are installed between the battery stack Bs on the Y- side and the case 80, between the two battery stacks Bs, and between the battery stack Bs on the Y+ side and the case 80. The spacers 89 are made of a material such as resin.

[0024] Each battery cell 70 has a positive electrode p (see Figs. 2, 13, etc.) at one end in the Y direction on the upper surface of the exterior, and a negative electrode n (see Fig. 13, etc.) at the other end in the Y direction on the upper surface of the exterior. Specifically, for a certain number of battery cells 70, the positive electrode p is arranged on the Y- direction side, and the negative electrode n is arranged on the Y+ direction side. On the other hand, for the other battery cells 70, the negative electrode n is arranged on the Y- direction side, and the positive electrode p is arranged on the Y+ direction side.

[0025] The electrodes p, n of the battery cells 70 adjacent in the Y direction or the X direction are electrically connected to each other by a conductive member not shown. On the other hand, the positive electrode p of the battery cell 70 that is electrically the most positive is electrically connected to the positive electrode P of the entire battery pack 100 by a conductive member not shown. In addition, the negative electrode n of the battery cell 70 that is electrically the most negative is electrically connected to the negative electrode N of the entire battery pack 100 by another conductive member not shown. As described above, in this embodiment, all of the battery cells 70 in the battery pack 100 are connected in series.

[0026] 2, each battery cell 70 has a safety valve 76 capable of discharging gas inside the battery cell 70, located in the center of the upper surface of the exterior. Specifically, the portion constituting the safety valve 76 on the upper surface of the exterior of each battery cell 70 is configured to be weaker than other portions. For this reason, when the pressure inside the battery cell 70 increases, that is, when the pressure inside the exterior increases, the portion constituting the safety valve 76 in the exterior is destroyed first, and pressure is released from here.

[0027] The flow path member 60 is an insulating member made of resin or the like, and is provided for each battery stack Bs. Each flow path member 60 is provided on the upper surface of its corresponding battery stack Bs.

[0028] 2, 7, etc., the cell retaining plate 30 is a long, plate-like member extending in the X direction, and is arranged parallel to the X direction at the center of the top surface of the pair of battery stacks Bs in the battery pack 100 and at both ends in the Y direction. The cell retaining plate 30 absorbs variations in the height of the battery cells 70 by sandwiching variations in an upper member 92 (described below) of the restraining member 90 together with the cover 20 from above.

[0029] The cell retaining plate 30 is made of a material such as metal. A flow path forming portion (not shown) through which the refrigerant flows is formed in a portion of the cell retaining plate 30 located above the flow path member 60. The cover 20 is formed in a rectangular plate shape as shown in FIG. 7 etc., and covers the cell retaining plate 30 from above. The cover 20 is made of a material such as metal. The cover 20 constitutes a water jacket for flowing the refrigerant in the flow path member 60.

[0030] The stacked cell ASSY, which is configured by arranging end plates 95 at the ends of the battery modules 200 in the stacking direction (the horizontal, lateral direction), has a battery stack Bs, a restraining member 90, and an end plate 95. As shown in Fig. 9 and other figures, the restraining member 90 has a lower member 91 and an upper member 92, and the restraining member 90 maintains the battery cells 70 in the battery stack Bs in a pressurized state. The lower member 91 has a rectangular lower frame portion 911 with an opening 913 that opens in the center, and side wall portions 912 that rise upward from a pair of long sides of the lower frame portion 911, and restrains the multiple battery cells 70 from the underside of the battery stack Bs.

[0031] 9, 10, 12, etc., the lower frame portion 911 forms a continuous annular frame that goes around the periphery of the lower end of the battery stack Bs. With this configuration, the lower frame portion 911 is assembled and positioned so as to go around the periphery of the lower end of the battery stack Bs, and as a result, the lower frame portion 911 restrains the lower end of the battery stack Bs in the stacking direction of the multiple battery cells 70 in the battery stack Bs.

[0032] The side walls 912 face each other and cover the battery stack Bs from the lower end of the side surface to the vicinity of the upper end of the side surface. As shown in FIG. 14, at the upper end of the side walls 912, multiple trapezoidal projections 916 are located above the upper surface of the upper member 92, projecting upward from the upper edge of the side walls 912. As shown in FIG. 13, the upper member 92 and the lower member 91 are fitted or joined by adhesive at the side surface of the outer periphery of the battery stack Bs. By joining the upper member 92 and the lower member 91, the restraining member 90 has a shape in which the upper and lower surfaces are entirely open, and both end surfaces in the stacking direction of the battery stack Bs are open. For convenience of explanation, the projections 916 are omitted in the figures other than FIG. 14.

[0033] On the outer surface of the side wall portion 912, multiple trapezoidal protrusions 915 protrude in a direction away from the outer surface of the side wall portion 912. The protrusions 915 are configured to be able to be appropriately crushed by being pressed inwardly into the battery stack Bs from the side by the side wall portion 912 of the lower member 91. This allows the protrusions 915 to absorb variations in length in the cell length direction of the battery cells 70.

[0034] The upper member 92 has a rectangular upper frame portion 921 with an opening 923 that opens in the center, and restrains the multiple battery cells 70 from above the battery stack Bs. As shown in Figures 9, 11, etc., the upper frame portion 921 forms a seamless annular frame that goes around the periphery of the upper end of the battery stack Bs. With this configuration, the upper frame portion 921 is assembled and positioned so as to go around the periphery of the upper end of the battery stack Bs, and as a result, the upper frame portion 921 restrains the upper end of the battery stack Bs in the stacking direction of the multiple battery cells 70 in the battery stack Bs.

[0035] 13, a plurality of trapezoidal protrusions 925 protrude upward from the top surface of the long side of the upper member 92. The protrusions 925 are configured to be able to be appropriately crushed by being pressed downward from above by the cell retaining plate 30 and the cover 20. This absorbs variations in the height of the battery cells 70.

[0036] The end plate 95 is attached to the front surface in the stacking direction of the multiple battery cells 70 attached to the restraining member 90, i.e., to an end surface of the battery stack Bs in the same direction. Specifically, the end plate 95 is formed into a rectangular resin plate and is fixed between the battery stack Bs and the lower frame portion 911 and upper frame portion 921 (see Figure 9, etc.) of the upper member 92 and lower member 91, as well as between the front wall of the case 80 (see Figures 3, 6, etc.) and the battery stack Bs.

[0037] The peripheral portion of the end plate 95 is configured to be thin. Therefore, the portion other than the peripheral portion has a convex portion 951 that is thicker than the peripheral portion, as shown in Fig. 3. The relatively thick convex portion 951 protrudes from the constraining member 90 in the stacking direction of the battery stack Bs, from the openings at the end faces of both ends of the constraining member 90 in the stacking direction, as shown in Fig. 3 etc. As a result, the convex portion 951 protrudes from the constraining member 90 toward the spacer 85, which serves as a pressure member that applies pressure to the battery stack Bs.

[0038] Next, a method for assembling the battery pack 100 having the above configuration will be described. First, an overview (image) of the method for assembling the battery pack 100 will be described. In a method of assembling the battery pack 100, first, as shown in Fig. 8, a battery module 200 is assembled in a state in which the battery stack Bs is pressed in the stacking direction of the battery cells 70 in the battery stack Bs and is restrained by the restraining members 90. That is, as shown in Fig. 19, the upper member 92 and lower member 91 constituting the restraining member 90 are assembled into the battery stack Bs in a state in which the battery stack Bs is pressed in the stacking direction of the battery cells 70, with the upper member 92 being assembled from above and the lower member 91 being assembled from below, as shown in Fig. 20. Next, as shown in Fig. 21, the protrusion 916 of the lower member 91 is grasped and suspended by a grasping jig 507, and the lower member 91 is inserted into the case 80, and as shown in Fig. 22, it is pushed into the case 80 from above.

[0039] A specific method for assembling the battery pack 100 is as follows. In the method for assembling the battery pack 100, an assembly jig 500 shown in Fig. 15 is used. The assembly jig 500 includes a base plate 501, a round bar 502A (see Figs. 19, 26 to 30) constituting a pressing wall 502 or a pressing jig as a pressing device, a push-up jig 503, a push-up pin 504, and a pressing jig 505 as a pressing device constituted by a round bar.

[0040] In assembling the battery pack 100, first, the lower frame portion 911 of the lower member 91 is set in the groove 5031 formed in the upper surface of the push-up jig 503, as shown in Fig. 23. Next, the battery stack Bs is inserted into the lower member 91 from above, as shown in Fig. 24, until the battery stack Bs is in a position where it can be installed in the lower member 91, as shown in Fig. 25.

[0041] Next, as shown in Figures 26 and 27, the battery stack Bs is sandwiched between a pressure jig 505 and a round bar 502A in the stacking direction of the battery cells 70 of the battery stack Bs, and pressure is applied from both sides in the stacking direction. The pressure applied at this time is between 0.5 KN and 1.5 KN. This is because a pressure of less than 0.5 KN will not provide sufficient compression, and a pressure of more than 1.5 KN will damage the battery cells 70 that make up the battery stack Bs. Note that if the pressing wall 502 (see Figures 15 to 18) that makes up the pressing jig is used instead of the round bar 502A (see Figures 19, 26 to 30) that makes up the pressing jig, the battery stack Bs is pressed from the side of the pressing jig 505.

[0042] 28 and 29, when the battery stack Bs is compressed to a predetermined distance by pressure, the lower member 91 is inserted so as to cover from below the multiple battery cells 70 stacked horizontally (the lateral direction). More specifically, as shown in Figures 17 and 18, the push-up jig 503 and push-up pins 504 are raised to push up the lower member 91, and the lower member 91 is inserted into the battery stack Bs from below.

[0043] Next, as shown in Figure 28, an upper member 92 that covers the top surfaces of the battery cells 70 is fitted from above the multiple battery cells 70 that are stacked horizontally (i.e., in the lateral direction) under pressure. In particular, as shown in Figures 28 and 29, the upper member 92 is fitted from above the pressurized battery stack Bs so as to surround the entire periphery of the upper part of the battery stack Bs.

[0044] Then, the upper members 92 and lower members 91 assembled above and below the battery stack Bs are fitted or joined by adhesive to the side surfaces of the outer periphery of the battery stack Bs. Then, as shown in FIG. 30, the pressing tool 505 and the round bar 502A, which have been pressing the battery stack Bs while sandwiching it, are separated from each other. The above steps are the steps in the method of assembling the battery pack 100 until the assembly of the battery module 200 is completed. Note that an end plate 95 is disposed on the outer surface of the end of the battery stack Bs in the stacking direction, with its thick portion protruding from the restraining member 90. The battery module 200 is then assembled into the case 80, and the assembly of the battery pack 100 is completed.

[0045] The above embodiment has the following advantages. In this embodiment, the restraining member 90 of the battery module 200 that constitutes the battery pack 100 is composed of an upper member 92 and a lower member 91, the upper member 92 is a frame member for restraining the upper side of the multiple battery cells 70 stacked in the horizontal direction, the lower member 91 is a frame member for restraining the lower side of the multiple battery cells 70 stacked in the horizontal direction, and the restraining member 90 restrains the stacked multiple battery cells 70 in the stacking direction.

[0046] This allows the multiple battery cells 70 to be fixed in a compressed state while being restrained by the restraining member 90 as a frame. This makes it possible to reduce the volume occupied by incidental parts other than the battery cells 70 in the IPU (intelligent power unit), increase the cell filling rate, and extend the driving range of a BEV (battery electric vehicle). In particular, since the upper member 92 and the lower member 91 are configured as a seamless frame incorporated into the stacked multiple battery cells 70, it becomes possible to reliably restrain the battery cells 70 by the restraining member 90.

[0047] Furthermore, in this embodiment, the upper member 92 and lower member 91 of the battery module 200 are joined by fitting or bonding at the side portions of the outer periphery of the stacked battery cells 70. This allows the lower member 91 to be positioned outside the upper member 92 and joined to the upper member 92. This makes it possible to use the lower member 91 for purposes other than restraining as the restraining member 90, for example, by providing a protrusion 916 at the upper end of the lower member 91 and gripping the protrusion 916 to transport the battery module 200. Furthermore, by forming the upper and lower parts of the restraining member 90 into an integrated structure, the number of parts can be reduced, which allows costs to be reduced.

[0048] In this embodiment, the upper member 92 is configured to cover the upper ends of the multiple battery cells 70 stacked in the horizontal direction, and is open to the upper surfaces of the multiple battery cells 70 stacked in the horizontal direction. The lower member 91 is configured to cover the lower ends of the multiple battery cells stacked in the horizontal direction, and is open to the lower surfaces of the multiple battery cells stacked in the horizontal direction. The end in the stacking direction of the restraining member 90 that restrains the multiple stacked battery cells 70 is open.

[0049] This makes it possible to create a frame structure that covers and restrains the entire upper and lower ends of the battery stack Bs having the battery cells 70, and makes it possible to prevent the restraining members 90 from moving relative to the battery cells 70 of the battery stack Bs when the reaction force due to compression of the battery cells 70 decreases.

[0050] In this embodiment, the method of assembling the battery module 200 includes the steps of setting the multiple battery cells 70 in a stacked state in an assembly jig 500, applying pressure to the set multiple battery cells 70 in the stacking direction using a pressure jig 505 as a pressure device, incorporating a lower member 91 so as to cover from below the multiple battery cells 70 stacked in the horizontal direction, which is the lateral direction, when the multiple battery cells 70 are compressed to a predetermined distance by being pressurized, incorporating an upper member 92 that covers the upper surfaces of the battery cells 70 from above the multiple pressurized horizontally stacked battery cells 70, and joining the upper member 92 and lower member 91 incorporated above and below the battery cells 70.

[0051] More specifically, for example, the lower side of the assembly jig 500 has a push-up jig 503 including push-up pins 504 as push pins, and a groove 5031 as a groove portion, and in the step of assembling the lower member 91, the lower member 91 is set in the groove 5031, and the push-up jig 503 including the push-up pins 504 pushes up the lower member 91 to assemble the multiple battery cells 70 stacked in the lower member 91. This allows the battery stack Bs as the stacked battery cells 70 to be fixed to the restraining member 90 without being lifted. This makes it possible to obtain a battery module 200 with good assembly properties.

[0052] Furthermore, in this embodiment, in the step of pressurizing the battery cells 70, the stacked battery cells 70 are fixed to an assembly jig 500, and compressed by a pressure of 0.5 KN or more and 1.5 KN or less using a pressure jig 505. This makes it possible to appropriately compress the entire length of the battery stack Bs made up of the stacked battery cells 70 to a predetermined distance (predetermined length).

[0053] In this embodiment, in the step of pressurizing the battery stack Bs, pressure is applied to the stacked battery cells 70 from one side or both sides in the stacking direction, which makes it possible to pressurize the battery stack Bs from one side or both sides as appropriate.

[0054] Furthermore, in this embodiment, in the process of fitting the lower member 91, the lower member 91 is pushed up from the lower side of the assembly jig 500 and fitted from below the stacked multiple battery cells 70. More specifically, in the process of fitting the lower member 91, the lower member 91 is pushed up by the push pins 504 of the assembly jig 500. This makes it possible to lift the lower member 91 without lowering the battery stack Bs, making it possible to prevent the structure of the assembly jig 500 from becoming complicated.

[0055] Furthermore, in this embodiment, in the process of assembling the upper member 92, the upper member 92 is assembled from above the stacked battery cells 70 with the lower member 91 assembled on the lower side. This makes it possible to assemble the upper member 92 from above without lifting the battery stack Bs, thereby preventing the configuration of the assembly jig 500 from becoming complicated.

[0056] In the present embodiment, in the process of joining the upper member 92 and the lower member 91, the upper member 92 and the lower member 91 are joined by fitting or welding. This makes it possible to reduce the number of parts by making the upper and lower members of the restraining member 90 into an integrated structure, thereby enabling costs to be reduced.

[0057] Furthermore, in the present embodiment, in the battery pack 100, an end plate 95 is provided on the outer surface of the stacked cell ASSY in the stacking direction of the multiple battery cells 70, and the outer surface of the end plate 95 contacts a pressing tool 505 which serves as a pressing device that pressurizes the stacked cell ASSY, and the outer surface of the end plate 95 which contacts the pressing tool 505 has a convex portion 951 which serves as a convex portion facing the pressing tool 505.

[0058] As a result, by pressing the convex portion 951, a compressive load is applied to the entire surface of the end plate 95 on the side opposite the convex portion 951 in the stacking direction of the battery cells 70 of the battery stack Bs. Therefore, by applying pressure integrally with the end plate 95, it is possible to uniformly press the stacked cell ASSY. Furthermore, by applying pressure to the convex portion 951 of the end plate 95, when the stacked cell ASSY is pressed evenly, pressure is applied to a limited range in the center of the battery cell 70, and as described above, it is possible to uniformly press the stacked cell ASSY. Furthermore, since the multiple battery cells 70 can be compressed by applying pressure to the convex portion 951 before assembly into the case 80, it is possible to reduce restrictions during mass production.

[0059] In this embodiment, the end plates 95 are fitted to end faces in the stacking direction of the multiple battery cells 70 fitted to the restraining member 90. The end plates 95 are fixed between the battery cells 70 and an upper frame portion 921 and a lower frame portion 911 serving as frames of the upper member 92 and the lower member 91. A portion 951 serving as a convex portion of the end plates 95 protrudes from the restraining member 90 towards a pressing jig 505 serving as a pressing member.

[0060] As a result, by applying pressure to the convex portion 951 toward the battery cell 70, it is possible to apply pressure evenly across the entire surface of the battery cell 70 of the battery stack Bs on the side of the end plate 95 opposite the convex portion 951.

[0061] The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of the present invention that can achieve the object of the present invention. For example, instead of the lower member 91 and the upper member 92, the restraining member may have a configuration including a pair of members having one end and the other end in a direction other than the up-down direction, for example, in the left-right direction. In addition, in the process of assembling the upper member 92, instead of assembling the upper member 92 from above the stacked multiple battery cells with the lower member 91 assembled on the bottom side, the upper member 92 may be assembled from above the stacked multiple battery cells before the lower member 91 is assembled on the bottom side. [Explanation of symbols]

[0062] 70 Battery Cells 80 cases (storage cases) 85 Spacer 90 Restraint member (cell assembly case) 91 Lower member (other end member) 92 Upper member (one end member) 95 End Plate 100 Battery Pack 200 Battery Module 500 Assembly Jig 504 Push-up pin 505 Pressurizing tool (pressurizing device) 801 Through hole 913, 923 Opening 916 Projection (grasped part) 951 Convex shaped part (convex shaped part)

Claims

1. A plurality of stacked battery cells; a restraining member that restrains the stacked battery cells in a stacking direction of the battery cells, the restraint member is configured with a one end side member and an other end side member for restraining the plurality of battery cells, the one-end member is a frame member for restraining an upper side of the plurality of battery cells stacked in the horizontal direction, the other end side member is a frame member for restraining a lower side of the plurality of battery cells stacked in the horizontal direction, the one end member and the other end member are joined to each other at an outer periphery of the stacked battery cells, The restraining member is a battery module that restrains the stacked battery cells in a stacking direction.

2. The battery module according to claim 1 , wherein the stacked battery cells are in a pressurized state.

3. The battery module according to claim 1 , wherein the one end member and the other end member are joined at side portions of outer peripheries of the stacked battery cells.

4. The battery module according to claim 3 , wherein the other end member is located outside the one end member and joined to the one end member.

5. The battery module according to claim 1 , wherein the one end member and the other end member are joined by fitting or bonding.

6. the one-end member is configured to cover upper ends of the plurality of battery cells stacked in the laterally direction and is open to upper surfaces of the plurality of battery cells stacked in the laterally direction; The battery module according to claim 1 , wherein the other end member is configured to cover lower ends of the plurality of battery cells stacked in the horizontal direction and is open to lower surfaces of the plurality of battery cells stacked in the horizontal direction.

7. The battery module according to claim 1 , wherein an end portion of the restraining member that restrains the stacked battery cells in the stacking direction is open.

8. 2. The battery module according to claim 1, wherein the other end member is configured to cover the plurality of battery cells stacked in the horizontal direction from their lower ends to their side faces, and an upper end of the other end member is located above an upper surface of the one end member.

9. The battery module according to claim 8 , wherein an upper end of the other end member has a protrusion located above an upper surface of the one end member.

10. An assembly method for assembling a restraining member composed of a one-end member and an other-end member to a plurality of stacked battery cells, comprising: setting the plurality of battery cells in a stacked state in an assembly jig; applying pressure to the set plurality of battery cells in a stacking direction using a pressure device; a step of incorporating the other end side member so as to cover the multiple battery cells stacked in the horizontal direction from below when the multiple battery cells are compressed to a predetermined distance by applying pressure; a step of assembling the one-end side member to cover the upper surfaces of the battery cells from the upper surfaces of the plurality of battery cells stacked in the pressed lateral direction; a step of joining the one end side member and the other end side member that are assembled above and below the battery cell; A method for assembling a battery module comprising the steps of:

11. The lower portion of the assembly jig has a push-up jig including a push pin and a groove portion, 11. The battery module assembly method according to claim 10, wherein in the step of incorporating the other-end side member, the other-end side member is set in the groove portion, and the other-end side member is pushed up by a push-up jig including the push pin, to incorporate the stacked multiple battery cells into the other-end side member.

12. The method for assembling a battery module according to claim 10 , wherein in the pressurizing step, pressure is applied to the stacked battery cells from one side or both sides in a stacking direction.

13. 12. The battery module assembly method according to claim 11, wherein in the step of incorporating the one-end side member, the one-end side member is incorporated from above the stacked multiple battery cells into which the other-end side member has been incorporated on the lower side, or from above the stacked multiple battery cells before the other-end side member has been incorporated on the lower side.

14. The method for assembling a battery module according to claim 10 , wherein in the step of joining the one end member and the other end member, the one end member and the other end member are joined by fitting or welding.

15. The method for assembling a battery module according to claim 10 , wherein the one end member and the other end member each have an annular shape and constitute a frame for fixing the plurality of battery cells.

16. The method for assembling a battery module according to claim 10 , wherein the other end side member has a grippable portion that can be gripped when the stacked battery cells to which the restraining member is attached are housed in a battery module case.

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