Battery module assembly method and holding mechanism

Abstract

SOLUTION: An assembly method of a battery module 10 includes: a region forming step of forming a region R in which a cell stack 12 can be disposed between a pair of holding plates 34 by applying a forced deformation force that deforms at least one of the pair of holding plates 34 against an elastic biasing force; a disposing step of disposing the cell stack 12 in the region R formed by the region forming step; and a pressing step of pressing the cell stack 12 in a stacking direction by the elastic biasing force by removing a forced deformation force in a state in which the cell stack 12 is disposed in the region R.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a battery module assembly method and a holding mechanism. [Background technology]

[0002] Patent Document 1 discloses a battery module including a cell stack formed by stacking battery cells and a heat exchanger. The battery module further includes a battery frame as a holding mechanism that holds the cell stack by applying a tightening load from both sides of the cell stack. The battery frame prevents the battery cells and the heat exchanger from moving.

[0003] The battery frame has a pair of spring plates and four rod-shaped connecting members that connect the pair of spring plates. The spring plates have four arms that protrude radially from the center. When assembling the cell stack to the battery frame, a tightening force is applied to the cell stack by tightening the screw structures (bolts and nuts) provided at both ends of the connecting members, thereby holding the cell stack in place. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-101130 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, because a pair of retaining plates are fixed to the connecting members by multiple screw structures, it is difficult to equalize the distances between the nuts at both ends of the connecting members among the multiple connecting members, which makes it difficult to equalize the stress acting on the multiple connecting members.

[0006] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] A first aspect of the present invention is a method for assembling a battery module comprising: a cell stack having battery cells and heat exchangers stacked on the battery cells; and a holding mechanism that holds both ends of the cell stack in the stacking direction, wherein the holding mechanism has a pair of elastically deformable holding plates and a plurality of connecting members that connect the pair of holding plates to each other; the method holds the cell stack by pressing the cell stack inward in the stacking direction with the elastic spring force of the pair of holding plates, the method comprising: a region forming step of forming a region between the pair of holding plates in which the cell stack can be placed by applying a forced deformation force that deforms at least one of the pair of holding plates against the elastic spring force; an arrangement step of placing the cell stack in the region formed by the region forming step; and a pressing step of pressing the cell stack in the stacking direction with the elastic spring force by removing the forced deformation force with the cell stack placed in the region.

[0008] A second aspect of the present disclosure is a holding mechanism comprising a pair of elastically deformable holding plates facing each other and a plurality of connecting members connecting the pair of holding plates to each other, and capable of holding an object placed between the pair of holding plates by the elastic biasing force of the pair of holding plates, wherein each of the plurality of holding plates has a pressing portion and a plurality of arm portions extending from the pressing portion toward the plurality of connecting members, and the plurality of arm portions are connected to the plurality of connecting members, and an external force from outside the pair of holding plates can move the pressing portion in a direction widening the gap between the pair of holding plates. [Effects of the Invention]

[0009] According to the present invention, by applying a forcible deformation force to the holding plate from the outside, an area in which a cell stack can be placed can be formed. Furthermore, by removing the forcible deformation force, the cell stack can be held by the elastic biasing force of the holding plate. This eliminates the need to fasten the holding plate with a screw structure, and the holding plate and the connecting members can be fixed in a position that cannot be adjusted. This allows for equalization of stress acting on multiple connecting members. As a result, a fastening force can be effectively applied to the cell stack. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a battery module. [Figure 2] FIG. 2 is an exploded perspective view of the cell stack. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. [Figure 4] Fig. 4A is an explanatory diagram of a preparation step of the area forming step in the battery module assembling method according to the first embodiment, and Fig. 4B is an explanatory diagram of a movement step of the area forming step. [Figure 5] Fig. 5A is an explanatory diagram of the arrangement step, and Fig. 5B is an explanatory diagram of the pressing step. [Figure 6] FIG. 6 is a perspective view of the engagement structure. [Figure 7] Fig. 7A is an explanatory view of an engaging step in the area forming step in the battery module assembling method according to the second embodiment, and Fig. 7B is an explanatory view of a moving step in the area forming step. [Figure 8] Fig. 8A is an explanatory diagram of a preparation step of the area forming step in the battery module assembling method according to the third embodiment, and Fig. 8B is an explanatory diagram of a moving step of the area forming step. [Figure 9] FIG. 9 is a schematic diagram of an aircraft on which a battery module is mounted. DETAILED DESCRIPTION OF THE INVENTION

[0011] 9, the battery module 10 is mounted on, for example, an aircraft 102 serving as a moving body 100. The aircraft 102 is, for example, an electric vertical take-off and landing aircraft (eVTOL). The aircraft 102 includes an airframe 104, a plurality of (for example, four) VTOL rotors 106, and a plurality of (for example, two) cruise rotors 108.

[0012] The VTOL rotor 106 generates an upward thrust for the aircraft 102. The cruise rotor 108 generates a horizontal thrust for the aircraft 102. The battery module 10 is disposed inside the airframe 104. The battery module 10 supplies power to electric motors (not shown) that drive the VTOL rotor 106 and the cruise rotor 108. The moving body 100 may be, for example, a vehicle, a ship, or the like. Note that the battery module 10 is not limited to being mounted on the moving body 100.

[0013] As shown in FIG. 1, the battery module 10 includes a cell stack 12 and a plurality of battery frames 16.

[0014] As shown in Fig. 2, the cell stack 12 has a plurality of battery cells 18 and a plurality of heat exchangers 20. The plurality of battery cells 18 arranged in the direction of the arrow X constitute one cell row 19. In this embodiment, four cell rows 19 are arranged in the direction of the arrow Y. The number of cell rows 19 may be three or less, or four or more. Only one cell row 19 may be provided in the battery module 10.

[0015] The plurality of battery cells 18 and the plurality of heat exchangers 20 are arranged (stacked) in the direction of the arrow X. Hereinafter, in this specification, the X direction is also referred to as the "stacking direction." In addition, within the X direction, the direction toward the center of the battery module 10 is expressed as the "inward in the stacking direction." Within the X direction, the direction away from the center of the battery module 10 is expressed as the "outward in the stacking direction."

[0016] The battery cell 18 is a laminated battery. The battery cell 18 is formed in the shape of a rectangular plate. A plurality of terminal portions 22 protrude from one side of the battery cell 18 in the direction of arrow Z. The plurality of battery cells 18 are connected in series to one another via the terminal portions 22. The terminal portions 22 are illustrated conceptually. Electrical connecting members (not shown) are joined to the plurality of terminal portions 22.

[0017] The multiple heat exchangers 20 include multiple first heat exchangers 20a and multiple second heat exchangers 20b. As shown in FIG. 2, each first heat exchanger 20a has a plate-shaped water jacket 24, a water supply / drainage header 26, and a turn header 28. The water jacket 24 extends in the direction of arrow Y. A flow path through which cooling water flows is formed inside the water jacket 24. Although not shown in detail, this flow path has a forward flow path that flows cooling water from the water supply / drainage header 26 to the turn header 28, and a return flow path that flows cooling water from the turn header 28 to the water supply / drainage header 26.

[0018] The water supply / drainage header is provided at one end (Y1 direction side) in the longitudinal direction (arrow Y direction) of the water jacket 24. The water supply / drainage header supplies and discharges cooling water to and from the water jacket .

[0019] The water supply / drain header 26 has a water supply port 30 and a drain port 32. The water supply port 30 supplies cooling water to the forward flow path of the water jacket 24. The water supply ports 30 of adjacent first heat exchangers 20a are liquid-tightly connected to each other. The drain port 32 discharges cooling water from the return flow path of the water jacket 24. The drain ports 32 of adjacent first heat exchangers 20a are liquid-tightly connected to each other.

[0020] Although not shown in detail, the water supply ports 30 of adjacent first heat exchangers 20a are connected to each other so as to be relatively movable in the X direction so as to absorb expansion of the battery cells 18 in the X direction due to heat generation or deterioration of the battery cells 18. Similarly, the water discharge ports 32 of adjacent first heat exchangers 20a are connected to each other so as to be relatively movable in the X direction.

[0021] The turn header 28 is provided at the other longitudinal end (Y2 direction side) of the water jacket 24. The turn header 28 receives cooling water from the forward flow path of the water jacket 24 and sends the cooling water to the return flow path of the water jacket 24.

[0022] Similar to the first heat exchanger 20a, the second heat exchanger 20b has a water jacket 24, a water supply / drainage header 26, and a turn header 28. However, the second heat exchanger 20b is arranged in a different orientation in the Y direction from the first heat exchanger 20a. Therefore, in the first heat exchanger 20a, the water supply / drainage header 26 is arranged on the Y2 side of the water jacket 24, and the turn header 28 is arranged on the Y1 side of the water jacket 24.

[0023] The first heat exchanger 20a and the second heat exchanger 20b are arranged alternately in the direction of the arrow X. Therefore, the water supply / drainage header 26 of one of the first heat exchanger 20a and the second heat exchanger 20b and the turn header 28 of the other of the first heat exchanger 20a and the second heat exchanger 20b are adjacent to each other in the stacking direction (X direction).

[0024] As shown in FIG. 3, two battery cells 18 are stacked in the direction of arrow X between a first heat exchanger 20a and a second heat exchanger 20b that are adjacent to each other.

[0025] 1, in this embodiment, four battery frames 16 are provided corresponding to four cell strings 19. The number of battery frames 16 may be three or less or five or more depending on the number of cell strings 19.

[0026] 1 and 3, the battery frame 16 includes a pair of holding plates 34, a pair of pressure-receiving plates 36, and a plurality of connecting members 38. The pair of holding plates 34 are located at the ends of the battery module 10 in the direction of arrow X. The battery frame 16 is a holding mechanism 17 that can hold a holding object (cell stack 12) placed between the pair of holding plates 34 by the elastic biasing force of the pair of holding plates 34.

[0027] The pair of holding plates 34 are located outward in the stacking direction of the battery cells 18. The holding plates 34 are made of, for example, a titanium alloy. However, the holding plates 34 may be made of a metal material other than a titanium alloy.

[0028] 1, the holding plate 34 is formed in an X-shape when viewed in the thickness direction of the holding plate 34 (the direction of the arrow X). The holding plate 34 has a point-symmetric shape. The holding plate 34 includes a plate center portion 40 and a plurality of arm portions 42.

[0029] The plate central portion 40 is a pressing portion 41 that presses the cell stack 12 in the stacking direction via the pressure-receiving plate 36. The plate central portion 40 is located at the center of the holding plate 34. The plate central portion 40 is located further inward in the stacking direction than the arm tip portions 44, which are the ends of the arm portions 42 in the extension direction. Therefore, when viewed from a direction perpendicular to the stacking direction, the holding plate 34 as a whole has a shape that convex inward in the stacking direction. A through hole 35 is formed in the plate central portion 40. The through hole 35 is formed in the center of the holding plate 34. When viewed from the X direction, the through hole 35 is circular. The function of the through hole 35 will be described later.

[0030] The multiple arm portions 42 extend radially from the plate central portion 40. The multiple arm portions 42 are provided at equal intervals in the circumferential direction of the plate central portion 40. The arm portions 42 are leaf spring portions that elastically deform when a tightening load is applied to the cell stack 12. In this embodiment, the holding plate 34 has four arm portions 42. Note that the number of arm portions 42 that the holding plate 34 has may be three or less or five or more.

[0031] In one of the holding plates 34, the arm tip 44, which is the end of the arm portion 42 in the extension direction, is connected to one end of the connecting member 38 by, for example, welding. In the other holding plate 34, the arm tip 44, which is the end of the arm portion 42 in the extension direction, is connected to the other end of the connecting member 38 by, for example, welding. That is, in the pair of holding plates 34, the arm tip 44 is fixed (secured) to both ends of the connecting member 38 in an unadjustable manner.

[0032] The arm tip 44 is located outward of the cell stack 12 when viewed from the stacking direction of the battery cells 18 (the direction of arrow X). The arm tip 44 does not overlap with the terminal portion 22 when viewed from the direction of arrow X. A positioning hole 34a is provided in the arm tip 44. The function of the positioning hole 34a will be described later.

[0033] The elastic force (spring force) of the four arms 42 is applied as a clamping load to the cell stack 12 via the pressure plate 36. This clamping load is the holding force of the holding plate 34 against the cell stack 12. The battery frame 16 holds the cell stack 12 solely by the frictional force generated by the force of the holding plate 34 pressing against the cell stack 12 via the pressure plate 36.

[0034] The pressure plate 36 is a pressing plate for uniformly applying the clamping load acting from the holding plate 34 to the cell stack 12. The pressure plate 36 is disposed between the holding plate 34 and the cell stack 12. The pressure plate 36 is formed in a rectangular shape. Note that the pressure plate 36 is not essential. Therefore, the cell stack 12 may be directly pressed by the plate center portion 40 without providing the pressure plate 36.

[0035] As shown in FIG. 3 , a threaded portion 37 is formed on the pressure-receiving plate 36. The function of the threaded portion 37 will be described later. Specifically, the threaded portion 37 is a female thread. In this embodiment, the threaded portion 37 passes through the pressure-receiving plate 36. Note that the threaded portion 37 does not have to pass through the pressure-receiving plate 36. The diameter of the threaded portion 37 is approximately the same as the diameter of the through hole 35 formed in the plate center portion 40 of the holding plate 34. Specifically, the diameter of the threaded portion 37 is slightly smaller than the diameter of the through hole 35. In other words, the diameter of the through hole 35 is slightly larger than the diameter of the threaded portion 37.

[0036] A first surface 36a of the pressure plate 36 facing the cell stack 12 is in surface contact with an end surface of the cell stack 12. A second surface 36b of the pressure plate 36 facing away from the cell stack 12 is in surface contact with a plate center portion 40 of the holding plate 34. The battery frame 16 does not necessarily have to have the pressure plate 36.

[0037] 1, when the holding plate 34 is attached to the pressure-receiving plate 36, the four arm portions 42 extend so as to overlap the four corners of the pressure-receiving plate 36 as viewed in the direction of the arrow X. When the holding plate 34 is attached to the pressure-receiving plate 36, gaps are provided between the arm portions 42 and the corners of the pressure-receiving plate 36. When the holding plate 34 is attached to the pressure-receiving plate 36, the four arm tip portions 44 are positioned outward from the pressure-receiving plate 36 as viewed in the direction of the arrow X.

[0038] The multiple connecting members 38 connect the pair of holding plates 34 to each other so that a clamping load (compression load) is applied from the pair of holding plates 34 to the cell stack 12. In this embodiment, the battery frame 16 has four connecting members 38. Each connecting member 38 is a shaft extending in the stacking direction of the battery cells 18. The connecting members 38 are made of a metal material such as stainless steel, for example.

[0039] In the battery frame 16 configured as described above, an external force from outside the pair of holding plates 34 can move the pressing portion 41 in a direction that widens the gap between the pair of holding plates 34 .

[0040] Next, a method for assembling the battery module 10 according to the first embodiment will be described.

[0041] The method for assembling the battery module 10 according to the first embodiment includes a region forming step, a placement step, and a pressing step.

[0042] 4A and 4B, in the region forming step, a forced deformation force is applied to deform at least one of the pair of holding plates 34 against the elastic biasing force of the holding plates 34, thereby forming a region R between the pair of holding plates 34 in which the cell stack 12 can be arranged. Here, a case in which both of the pair of holding plates 34 are deformed will be described, but only one of the holding plates 34 may also be deformed.

[0043] The region forming process includes a preparation process and a movement process. In the preparation process, first, as shown in FIG. 4A , an auxiliary jig 50 for forced deformation is attached to the outside of the holding plate 34. The auxiliary jig 50 has legs 52 that abut against the arm tips 44 of the holding plate 34. The legs 52 are provided with positioning protrusions 53. The positioning protrusions 53 are inserted into positioning holes 34a provided in the holding plate 34, thereby positioning the auxiliary jig 50 relative to the holding plate 34. Note that the positioning holes 34a may be provided in the auxiliary jig 50, and the positioning protrusions 53 may be provided in the holding plate 34.

[0044] In the preparation step, a shaft 56a (male thread) of a bolt 56 is inserted into a hole 54 provided in the center of the auxiliary jig 50. The bolt 56 is one aspect of a structural member for moving the plate center portion 40 in a direction that widens the gap between the pair of holding plates 34. The hole 54 is a hole without a thread. Therefore, the shaft 56a of the bolt 56 is not threaded into the hole 54. The shaft 56a of the bolt 56 penetrates the auxiliary jig 50 and is inserted into the through-hole 35 provided in the holding plate 34. At this time, the tip of the shaft 56a of the bolt 56 is slightly engaged (screwed) with the thread portion 37 provided in the pressure-receiving plate 36. In addition, the head 56b of the bolt 56 abuts against the auxiliary jig 50.

[0045] 4B , in the moving step of the region forming step, the bolt 56 is rotated while fixing its axial position, thereby moving the plate central portion 40 in a direction approaching the auxiliary jig 50 (outward in the X direction). Specifically, when the bolt 56 inserted into the auxiliary jig 50 is rotated, the shank 56a of the bolt 56 and the threaded portion 37 of the pressure-receiving plate 36 threadably engage with each other, forcibly displacing the plate central portion 40 toward the auxiliary jig 50 against the elastic biasing force of the holding plate 34. As the plate central portion 40 of each of the pair of holding plates 34 is displaced toward the auxiliary jig 50, a region R in which the cell stack 12 can be arranged is formed between the pair of holding plates 34 (between the pair of pressure-receiving plates 36 in the first embodiment).

[0046] Next, as shown in Fig. 5A, in the placement step, the cell stack 12 is placed in the region R formed in the region forming step. Note that when performing this assembly method, including the placement step, it is preferable to perform the steps so that the X direction is vertical. This allows the cell stack 12 to be placed on one of the pressure plates 36, making it easy to place the cell stack 12 in the region R formed in the region forming step. Note that Figs. 5A and 5B show the cell stack 12 in a simplified manner.

[0047] 5B , in the pressing step, with the cell stack 12 disposed in region R, the above-mentioned forced deformation force is removed, and the cell stack 12 is pressed in the stacking direction by the elastic biasing force of the holding plate 34. Specifically, the bolt 56 is rotated in the direction opposite to the rotation direction of the bolt 56 in the region forming step, and the bolt 56 is loosened, thereby displacing the holding plate 34 and the pressure-receiving plate 36 toward the cell stack 12. As a result, a clamping load is applied to the cell stack 12 by the pair of holding plates 34.

[0048] The first embodiment has the following advantages.

[0049] As shown in Fig. 5A, by applying a forcible deformation force to the holding plate 34 from the outside, a region R in which the cell stack 12 can be placed can be formed. Furthermore, as shown in Fig. 5B, by removing the forcible deformation force, the cell stack 12 can be held by the elastic biasing force of the holding plate 34. This eliminates the need to fasten the holding plate 34 to the connecting members 38 using a screw structure, and allows the holding plate 34 and the connecting members 38 to be fixed in a manner that makes their positions unadjustable. This allows for the stress acting on the multiple connecting members 38 to be uniformly distributed. As a result, a fastening force can be effectively applied to the cell stack 12.

[0050] 4B, in the region forming step, a forced deformation force is applied to the arm portion 42 while the end portion (arm tip portion 44) in the extension direction of the arm portion 42 is fixed, thereby deforming the arm portion 42. This allows the arm portion 42 to be deformed effectively.

[0051] In the region forming step, the plate central portion 40 (pressing portion 41) is moved in the direction opposite to the pressing direction applied to the cell stack 12 in the pressing step. This allows the region R in which the cell stack 12 can be arranged to be formed satisfactorily.

[0052] In the region forming step, the bolt 56 is threadedly engaged with the threaded portion 37 formed in the pressure-receiving plate 36, and the bolt 56 is rotated while the axial position of the bolt 56 is fixed, thereby moving the plate central portion 40. This allows the plate central portion 40 to be moved effectively. Note that the threaded portion 37 may be formed in the plate central portion 40. In this case, in the region forming step, the bolt 56 is threadedly engaged with the threaded portion 37 formed in the plate central portion 40, and the bolt 56 is rotated while the axial position of the bolt 56 is fixed, thereby moving the plate central portion 40. Alternatively, the threaded portion 37 may be formed in both the pressure-receiving plate 36 and the plate central portion 40.

[0053] In the region forming step, the bolt 56 inserted into the auxiliary jig 50 attached to the holding plate 34 is rotated. As a result, the plate center portion 40 of the holding plate 34 can be easily moved in accordance with the rotation of the bolt 56.

[0054] Next, a method for assembling the battery module 10 according to the second embodiment will be described.

[0055] As shown in FIG. 6, the plate center portion 40 of the holding plate 34 is provided with an engagement structure 70 that can engage with the displacement jig 60. The engagement structure 70 has a central hole 72, a slit 74, and an engagement groove 76. The slit 74 is capable of receiving the tip portion 62 of the displacement jig 60. In FIG. 6, a pair of slits 74 are formed extending in opposite directions from the central hole 72. The engagement groove 76 is capable of engaging with the tip portion 62 of the displacement jig 60 inserted through the slit 74. The engagement groove 76 is in communication with the slit 74.

[0056] The displacement jig 60 is one form of structural member for moving the plate central portion 40 in a direction that widens the gap between the pair of holding plates 34. A pair of engagement pins 64 is provided at the tip portion 62 of the displacement jig 60. The pair of engagement pins 64 can be inserted into a pair of slits 74 of the engagement structure 70. The pair of engagement pins 64 can be engaged with engagement grooves 76 of the engagement structure 70. It is noted that one engagement pin 64 and one slit 74 may be provided. Three or more engagement pins 64 and three or more slits 74 may be provided.

[0057] In the assembling method for the battery module 10 according to the second embodiment, the area forming step includes an inserting step, an engaging step, and a moving step. In the inserting step, the tip end 62 (a pair of engaging pins 64) of the displacement jig 60 is inserted into a pair of slits 74 of the engaging structure 70. Next, as shown in Fig. 7A, in the engaging step, the displacement jig 60 is rotated to engage the engaging pins 64 of the displacement jig 60 with the engaging grooves 76 of the engaging structure 70.

[0058] 7B, in the moving step, the holding plate 34 is forcibly displaced by pulling the displacement jig 60, and the plate central portion 40 is moved outward (outward in the X direction) from the battery frame 16. This forms a region R between the pair of holding plates 34 (between the pair of pressure-receiving plates 36 in the second embodiment) in which the cell stack 12 can be arranged.

[0059] Although not shown in the drawings, thereafter, the arrangement step and the pressing step are performed in the same manner as in the first embodiment. Specifically, in the second embodiment, the cell stack 12 is arranged in the formed region R. Thereafter, the tensile force on the displacement jig 60 is released to remove the forced deformation force on the holding plate 34, and the holding plate 34 and the pressure-receiving plate 36 are displaced toward the cell stack 12. As a result, a clamping load is applied to the cell stack 12 by the pair of holding plates 34.

[0060] The second embodiment also makes it possible to effectively apply a clamping force to the cell stack 12. In the second embodiment, the displacement jig 60 is engaged with the engagement structure 70, and the displacement jig 60 is pulled to forcibly deform the holding plate 34. This makes it possible to form the region R between the pair of holding plates 34 in a simple manner, in which the cell stack 12 can be arranged. The engagement structure 70 may also be provided on the pressure-receiving plate 36. In this case, an insertion hole is provided in the plate central portion 40 to allow the displacement jig 60 to pass through.

[0061] Next, a method for assembling the battery module 10 according to the third embodiment will be described.

[0062] 8A, a permanent magnet 80 is fixed to the plate center portion 40 of each of the pair of holding plates 34. The region forming step in the assembly method according to the third embodiment includes a preparation step and a movement step. In the preparation step, a pair of electromagnets 82 is arranged on the outside of the battery frame 16 so as to face the permanent magnets 80 fixed to the pair of holding plates 34 at a distance.

[0063] 8B, in the moving step, the plate center portion 40 is moved by an external magnetic force. Specifically, the pair of electromagnets 82 is energized, and the permanent magnets 80 are attracted toward the electromagnets 82 by magnetic force. This moves the plate center portion 40 outward (outward in the X direction) from the battery frame 16. This forms a region R between the pair of holding plates 34 (between the pair of pressure-receiving plates 36 in the third embodiment) in which the cell stack 12 can be placed.

[0064] Although not shown in the drawings, thereafter, in the third embodiment, a placement process and a pressing process are performed, similar to the first embodiment. Specifically, in the third embodiment, the cell stack 12 is placed in the formed region R. Thereafter, the energization of the pair of electromagnets 82 is stopped, thereby removing the forcible deformation force on the holding plate 34 and displacing the holding plate 34 and the pressure-receiving plate 36 toward the cell stack 12. As a result, a clamping load is applied to the cell stack 12 by the pair of holding plates 34.

[0065] The third embodiment also allows for a good clamping force to be applied to the cell stack 12. In the third embodiment, the plate center portion 40 is moved by an external magnetic force. Therefore, a region R in which the cell stack 12 can be arranged between the pair of holding plates 34 can be formed by a simple method. The plate center portion 40 may be configured so that the permanent magnet 80 can be attached and detached. If the plate center portion 40 is made of a metal material (ferromagnetic material) that can be attracted by the magnetic force of the permanent magnet 80, the permanent magnet 80 does not need to be provided.

[0066] The following additional notes are further disclosed regarding the above embodiment.

[0067] (Appendix 1) The method for assembling a battery module (10) disclosed herein comprises a cell stack (12) having battery cells (18) and heat exchangers (20) stacked on the battery cells, and a holding mechanism (17) that holds both ends of the cell stack in the stacking direction, the holding mechanism having a pair of elastically deformable holding plates (34) and a plurality of connecting members (38) that connect the pair of holding plates to each other, and the method holds the cell stack by pressing the cell stack inward in the stacking direction with the elastic biasing force of the pair of holding plates, the method comprising: a region forming step of forming a region (R) between the pair of holding plates in which the cell stack can be placed by applying a forced deformation force that deforms at least one of the pair of holding plates against the elastic biasing force; an arrangement step of placing the cell stack in the region formed by the region forming step; and a pressing step of pressing the cell stack in the stacking direction with the elastic biasing force removed with the cell stack placed in the region.

[0068] (Appendix 2) In the battery module assembling method described in Appendix 1, each of the pair of holding plates has a pressing portion (41) and an arm portion (42) extending from the pressing portion, and in the region forming process, the arm portion may be deformed by applying the forced deformation force while the end of the arm portion in the extension direction is fixed.

[0069] (Supplementary Note 3) In the battery module assembling method described in Supplementary Note 2, in the region forming step, the pressing portion may be moved in a direction opposite to a pressing direction applied to the cell stack in the pressing step.

[0070] (Appendix 4) In the battery module assembling method described in Appendix 3, at least one of the pressing portion or the pressure-receiving plate (36) placed on the pressing portion may be provided with a threaded portion (37), and in the region forming step, the pressing portion may be moved by threading a bolt (56) into the threaded portion and rotating the bolt while fixing the axial position of the bolt.

[0071] (Supplementary Note 5) In the battery module assembling method described in Supplementary Note 4, in the region forming step, the bolt inserted into an auxiliary jig (50) attached to the holding plate may be rotated.

[0072] (Appendix 6) In the battery module assembling method described in Appendix 3, the pressing portion or the pressure-receiving plate overlapping the pressing portion may be provided with an engagement structure (70) having a slit (74) and an engagement groove (76), and the region forming step may include an insertion step of inserting a tip end of a structural member into the slit of the engagement structure, an engagement step of rotating the structural member to engage the tip end with the engagement groove, and a movement step of pulling the structural member to move the pressing portion.

[0073] (Supplementary Note 7) In the battery module assembling method described in Supplementary Note 3, in the region forming step, the pressing portion may be moved by an external magnetic force.

[0074] (Appendix 8) The holding mechanism of the present disclosure comprises a pair of elastically deformable holding plates facing each other, and a plurality of connecting members connecting the pair of holding plates to each other, and is capable of holding an object placed between the pair of holding plates by the elastic force of the pair of holding plates, wherein each of the plurality of holding plates has a pressing portion and a plurality of arm portions extending from the pressing portion toward the plurality of connecting members, and the plurality of arm portions are connected to the plurality of connecting members, and an external force from outside the pair of holding plates can move the pressing portion in a direction widening the gap between the pair of holding plates.

[0075] (Supplementary Note 9) In the holding mechanism described in Supplementary Note 8, a structural member for moving the pressing portion in the direction in which the gap is widened may be attached to the pressing portion.

[0076] (Supplementary Note 10) In the holding mechanism described in Supplementary Note 9, the pressing portion may be formed with a thread portion that can be engaged with the structural member.

[0077] (Supplementary Note 11) In the holding mechanism described in Supplementary Note 9, a pressure-receiving plate placed on the pressing portion may be formed with a thread portion that can be engaged with the structural member.

[0078] (Supplementary Note 12) In the holding mechanism described in Supplementary Note 11, the pressing portion may be formed with a through hole (35) for inserting a bolt, which is the structural member.

[0079] (Supplementary Note 13) In the holding mechanism according to Supplementary Note 12, the diameter of the through hole may be substantially the same as the diameter of the screw portion.

[0080] (Appendix 14) In the holding mechanism described in appendix 12 or 13, the through hole may be formed in the center of the holding plate, and the threaded portion may be formed in the center of the pressure-receiving plate.

[0081] (Appendix 15) In the holding mechanism described in Appendix 9, the pressing portion or the pressure-receiving plate superimposed on the pressing portion may be provided with an engagement structure that can engage with the structural member, and the engagement structure may have a slit that can receive the tip of the structural member, and an engagement groove that can engage with the tip inserted through the slit.

[0082] (Appendix 16) In the holding mechanism described in Appendix 8, a permanent magnet (80) may be fixed to the pressing portion or may be attachable to the pressing portion for moving the pressing portion in the direction that widens the gap.

[0083] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0084] 10... Battery module 12... Cell stack 16... Battery frame 17... Retention mechanism 18... Battery cell 20... Heat exchanger 34...Holding plate 35...Through hole 36...Pressure plate 37...Threaded part 38...connecting member 41...pressing portion 42...Arm section

Claims

1. A method for assembling a battery module, comprising: a cell stack having battery cells and heat exchangers stacked on the battery cells; and a holding mechanism that holds both ends of the cell stack in a stacking direction, the holding mechanism having a pair of elastically deformable holding plates and a plurality of connecting members that connect the pair of holding plates to each other, and the cell stack is held by pressing the cell stack inward in the stacking direction with the elastic biasing force of the pair of holding plates, a region forming step of forming a region between the pair of holding plates in which the cell stack can be arranged by applying a forced deformation force that deforms at least one of the pair of holding plates against the elastic biasing force; a placement step of placing the cell stack in the region formed by the region formation step; a pressing step in which, with the cell stack placed in the region, the forced deformation force is removed, thereby pressing the cell stack in the stacking direction with the elastic force.

2. The battery module assembling method according to claim 1, Each of the pair of holding plates has a pressing portion and an arm portion extending from the pressing portion, The method for assembling a battery module, wherein in the region forming step, the arm portion is deformed by applying the forced deformation force while the end portion in the extension direction of the arm portion is fixed.

3. The battery module assembling method according to claim 2, a pressing portion that is moved in a direction opposite to a pressing direction applied to the cell stack in the pressing step;

4. The battery module assembling method according to claim 3, a threaded portion is provided on at least one of the pressing portion and the pressure-receiving plate overlapping the pressing portion, In the region forming step, a bolt is threaded into the threaded portion, and the pressing portion is moved by rotating the bolt while fixing the axial position of the bolt.

5. The battery module assembling method according to claim 4, The method for assembling a battery module, wherein the area forming step rotates the bolt inserted into an auxiliary jig attached to the holding plate.

6. The battery module assembling method according to claim 3, an engagement structure having a slit and an engagement groove is provided on the pressing portion or the pressure-receiving plate overlapping the pressing portion; The region forming step includes: an insertion step of inserting a tip end of a structural member into the slit of the engagement structure; an engaging step of rotating the structural member to engage the tip portion with the engaging groove; a moving step of moving the pressing portion by pulling the structural member.

7. The battery module assembling method according to claim 3, The method for assembling a battery module, wherein the region forming step moves the pressing portion by an external magnetic force.

8. A holding mechanism comprising a pair of elastically deformable holding plates facing each other and a plurality of connecting members connecting the pair of holding plates to each other, wherein an object to be held can be placed between the pair of holding plates by the elastic biasing force of the pair of holding plates, Each of the plurality of holding plates has a pressing portion and a plurality of arm portions extending from the pressing portion toward the plurality of connecting members, and the plurality of arm portions are connected to the plurality of connecting members, A holding mechanism that allows the pressing portion to move in a direction that widens the gap between the pair of holding plates by an external force from outside the pair of holding plates.

9. 9. The holding mechanism according to claim 8, A holding mechanism, wherein a structural member can be attached to the pressing portion for moving the pressing portion in the direction in which the gap is widened.

10. 10. The retention mechanism according to claim 9, A holding mechanism, wherein the pressing portion is formed with a thread portion that can engage with the structural member.

11. 10. The retention mechanism according to claim 9, A holding mechanism in which a pressure-receiving plate placed over the pressing portion has a threaded portion formed thereon that can engage with the structural member.

12. 12. The retention mechanism according to claim 11, A holding mechanism, wherein the pressing portion has a through hole formed therein for inserting a bolt, which is the structural member.

13. 13. The retention mechanism according to claim 12, A retention mechanism, wherein the diameter of the through hole is approximately the same as the diameter of the threaded portion.

14. 14. The holding mechanism according to claim 12 or 13, The through hole is formed in the center of the holding plate, The screw portion is formed in the center of the pressure plate.

15. 10. The retention mechanism according to claim 9, an engagement structure that can engage with the structural member is provided on the pressing portion or the pressure-receiving plate that is placed on the pressing portion; The engagement structure has a slit capable of receiving the tip of the structural member, and an engagement groove capable of engaging with the tip inserted through the slit.

16. 9. The holding mechanism according to claim 8, A holding mechanism in which a permanent magnet is fixed to the pressing portion or the permanent magnet can be attached to the pressing portion for moving the pressing portion in the direction in which the gap is widened.

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