Battery module

Abstract

SOLUTION: A battery module 10 includes a cell stack 12 having battery cells 18 and a heat exchanger 20, a holding mechanism 17 that holds the cell stack 12 by pressing both ends of the cell stack 12 inward in the stacking direction, and a detachment prevention mechanism 60 that prevents at least the heat exchanger 20 from falling off the cell stack 12.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a battery module. [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 holding mechanism (battery frame) 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-101130 Summary of the Invention [Problem to be solved by the invention]

[0004] The cell stack is held in place solely by frictional force due to the pressing force applied by the battery frame. Therefore, if a force exceeding the frictional holding force acts on the cell stack during an impact such as vibration, the heat exchanger or battery cells may move (misalign) in a direction perpendicular to the stacking direction. One solution to this problem is to increase the pressing force (clamping force) applied by the battery frame. However, this solution requires increasing the rigidity of the battery cells and the heat exchanger. Furthermore, this solution raises concerns about an increase in the clamping force acting on the battery cells when the battery cells expand due to heat generation or deterioration.

[0005] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] An aspect of the present disclosure is a battery module comprising: a cell stack having battery cells and a heat exchanger stacked on the battery cells; a holding mechanism that holds the cell stack by pressing both ends of the cell stack inward in the stacking direction; and a detachment prevention mechanism that prevents at least the heat exchanger from falling off the cell stack. [Effects of the Invention]

[0007] According to the present invention, even if an unexpected impact is applied to the battery module, the heat exchanger is supported by the anti-detachment mechanism. This prevents the heat exchanger from falling off the cell stack. Furthermore, since there is no need to increase the clamping force of the retention mechanism, it is possible to prevent the clamping force acting on the battery cells from becoming too large when the battery cells expand due to heat generation or deterioration of the battery cells. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a battery module according to one embodiment of the present invention. [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. 4 is a cross-sectional view of the anti-fall-off mechanism. [Figure 5] Fig. 5A is a schematic cross-sectional view taken along line VA-VA in Fig. 4. Fig. 5B is a schematic cross-sectional view showing a state in which the heat exchanger is supported by the fall-off prevention mechanism. [Figure 6] FIG. 6 is a schematic diagram of an aircraft on which a battery module is mounted. DETAILED DESCRIPTION OF THE INVENTION

[0009] 6, the battery module 10 according to this embodiment 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.

[0010] 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.

[0011] As shown in FIG. 1, the battery module 10 includes a cell stack 12 and a plurality of battery frames 16.

[0012] 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. The plurality of battery cells 18 and the plurality of heat exchangers 20 are arranged (stacked) in the direction of the arrow X. Hereinafter, the X direction will also be referred to as the "stacking direction." In addition, within the X direction, the direction toward the center of the battery module 10 will be referred to as the "inward direction in the stacking direction." Within the X direction, the direction away from the center of the battery module 10 will be referred to as the "outward direction in the stacking direction."

[0013] 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.

[0014] 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.

[0015] The water supply and drainage header 26 is one of a pair of headers provided in the first heat exchanger 20a. The water supply and drainage header 26 is provided at a first end, which is one end (Y1 direction side) in the longitudinal direction (arrow Y direction) of the water jacket 24. The water supply and drainage header 26 supplies and discharges cooling water to the water jacket 24. The water supply and drainage header 26 has a water supply port 30 and a drainage port 32. The water supply port 30 is provided at an upper part of the water supply and drainage header 26. 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 connected to each other in a liquid-tight manner.

[0016] The drain port 32 discharges the cooling water from the return flow path of the water jacket 24. The drain port 32 is provided in the lower part of the water supply / drainage header 26. The drain ports 32 of adjacent first heat exchangers 20a are liquid-tightly connected to each other. Note that, contrary to the above-described configuration, the water supply port 30 may be provided in the lower part of the water supply / drainage header 26 and the drain port 32 may be provided in the upper part of the water supply / drainage header 26.

[0017] 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.

[0018] The turn header 28 is the other of a pair of headers provided in the first heat exchanger 20a. The turn header 28 is provided at the second end, which is the other longitudinal end (Y2 direction side) of the water jacket 24. Therefore, the water jacket 24 is disposed between the water supply / drainage header 26 and the turn header 28. 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.

[0019] 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 second heat exchanger 20b, 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.

[0020] 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).

[0021] 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.

[0022] As shown in Fig. 1, in this embodiment, four battery frames 16 are provided corresponding to four cell rows 19. The number of battery frames 16 may be three or less or five or more depending on the number of cell rows 19. As shown in Figs. 1 and 3, the battery frame 16 is a holding mechanism 17 that holds the cell stack 12. The battery frame 16 includes a pair of holding plates 34, a pair of pressure-receiving plates 36, and four 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.

[0023] The holding plate 34 is a pressing portion 35 that presses the cell stack 12 in the stacking direction via a pressure-receiving plate 36. The pressure-receiving plate 36 is disposed between the holding plate 34 and the cell stack 12. The connecting member 38 connects 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. This suppresses expansion of the battery cells 18.

[0024] 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.

[0025] 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 four arm portions 42.

[0026] The plate central portion 40 is located at the center of the holding plate 34. The four arm portions 42 extend radially from the plate central portion 40. The four 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. The number of arm portions 42 is not limited to four, and may be three or five or more.

[0027] An attachment portion 44 is provided at the end of the arm portion 42 in the extending direction. The connecting member 38 is connected to the attachment portion 44. An insertion hole 45 is formed in the attachment portion 44, through which the bolt portion 48 of the connecting member 38 is inserted (see FIG. 3).

[0028] The attachment portion 44 is located outward of the cell stack 12 when viewed from the stacking direction (arrow X direction) of the battery cells 18. The attachment portion 44 does not overlap with the terminal portion 22 when viewed from the arrow X direction.

[0029] 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 formed in a rectangular shape. As shown in FIG. 3 , 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. Furthermore, 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. Note that the battery frame 16 does not necessarily have to have the pressure plate 36.

[0030] 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 mounting portions 44 are positioned outward from the pressure-receiving plate 36 as viewed in the direction of the arrow X.

[0031] As shown in FIG. 3 , the connecting member 38 includes a connecting shaft 46, two bolt portions 48, and two nuts 50. The connecting shaft 46 extends in the stacking direction of the battery cells 18. The connecting shaft 46 is made of a metal material such as stainless steel. The bolt portions 48 protrude from the axial end face of the connecting shaft 46. The bolt portions 48 are inserted into insertion holes 45 of the mounting portion 44. The nuts 50 are screwed onto the bolt portions 48. The mounting portion 44 is located between the nuts 50 and the connecting shaft 46.

[0032] When the nuts 50 are tightened onto the bolt portions 48, the holding plate 34 is pressed toward the pressure plate 36. At this time, the four arm portions 42 are elastically deformed. The elastic force (spring force) of the four arm portions 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.

[0033] 1 and 2, the battery module 10 further includes a detachment prevention mechanism 60. The detachment prevention mechanism 60 is a structure for preventing at least the heat exchanger 20 from falling off from the cell stack 12. The detachment prevention mechanism 60 has a through-hole 62 and a shaft 64. In this embodiment, the detachment prevention mechanism 60 is disposed at each end of the battery module 10 in the Y direction. That is, the battery module 10 includes a plurality of detachment prevention mechanisms 60.

[0034] The through holes 62 are holes formed in portions of the heat exchanger 20 that do not overlap with the battery cells 18 in the stacking direction (X direction). Specifically, the through holes 62 are formed in each of the water supply / drainage header 26 and the turn header 28 of the heat exchanger 20. In this embodiment, the through holes 62 are also positioning holes used to determine the installation position of the cell stack 12. That is, when installing the battery module 10 on an installation target (for example, the mobile body 100 shown in FIG. 6), a positioning shaft (not shown) is inserted into the through hole 62 to position the cell stack 12. In this embodiment, the through holes 62 are circular.

[0035] The through hole 62 (hereinafter also referred to as "through hole 62a") formed in the water supply and drainage header 26 penetrates the water supply and drainage header 26 in the stacking direction. The through hole 62a is formed between the water supply port 30 and the drainage port 32. The through hole 62a is formed in the lower part of the water supply and drainage header 26. Note that the through hole 62a may be formed in the upper part of the water supply and drainage header 26, or may be formed in the center of the water supply and drainage header 26 in the up-down direction.

[0036] The through-hole 62 (hereinafter also referred to as "through-hole 62b") formed in the turn header 28 penetrates the turn header 28 in the stacking direction. The through-hole 62b is formed in the lower part of the turn header 28. Note that the through-hole 62b may be formed in the upper part of the turn header 28, or may be formed in the center of the turn header 28 in the up-down direction.

[0037] 4, in the fall-off prevention mechanism 60, a plurality of through holes 62 are arranged in a straight line in the stacking direction (X direction). Therefore, a hole row is formed by the plurality of through holes 62 arranged in the stacking direction.

[0038] As shown in FIG. 5A, the through-hole 62a provided in the water supply / drainage header 26 is preferably circular. On the other hand, the through-hole 62b provided in the turn header 28 is preferably track-field shaped. That is, since the through-hole 62a is positioned at a substantially fixed position by the water supply port 30, it is preferable that the through-hole 62a be circular. On the other hand, the through-hole 62b is preferably track-field shaped with clearance in the Y direction relative to the shaft 64, taking into account dimensional variations in the longitudinal direction (Y direction) of each water jacket 24 (FIG. 2) and the influence of thermal elongation during use. The track-field shape of the through-hole 62b has a pair of semicircular arc portions 621 and a pair of linear portions 622 connecting the pair of arc portions 621. The major axis of the track-field shape of the through-hole 62b is aligned with the longitudinal direction of the water jacket 24 (FIG. 2). In this case, the radii of the plurality of through holes 62a and the radii of the arc portions 621 of the track field shape of the plurality of through holes 62b are all the same. The hole shapes of the through holes 62a and the through holes 62b do not have to be the above shapes, and any shape can be selected as long as the object of the present invention can be achieved. Examples include an ellipse and a rectangle.

[0039] As shown in FIG. 4, the shaft 64 is inserted through the through-hole 62 (a row of through-holes 62). The shaft 64 extends along the stacking direction of the cell stack 12. The heat exchanger 20 is movable relative to the shaft 64 in the stacking direction. The shaft 64 is longer than the dimension of the cell stack 12 in the stacking direction. Therefore, both ends of the shaft 64 protrude from the cell stack 12. Both ends of the shaft 64 are held by support portions 66 arranged on both sides of the stacking direction of the battery module 10. The shaft 64 prevents the heat exchanger 20 from falling off. In other words, the shaft 64 is a fall-off prevention shaft.

[0040] The support parts 66 are fixed to the floor of an object (for example, the moving body 100 shown in FIG. 6) on which the battery module 10 is to be installed. The support parts 66 support both ends of the shaft 64, thereby preventing the shaft 64 from moving in a direction perpendicular to the stacking direction (the axial direction of the shaft 64).

[0041] 5A, the cross-sectional shape of the shaft 64 is circular in a plane perpendicular to the axial direction of the shaft 64. Note that the cross-sectional shape of the shaft 64 is not limited to a circle, and may be, for example, an oval, a square, or the like.

[0042] 1, when the cell stack 12 is maintained in an initial position, which is the position at which it is initially pressed against the pressing portion 35 (holding plate 34) of the holding mechanism 17, the entire circumference of the outer circumferential surface 64s of the shaft 64 is separated from the inner circumferential surface 62s of the through hole 62, as shown in FIG. 5A. In other words, when the heat exchanger 20 is not displaced from the initial position, an annular space 70 is formed between the outer circumferential surface 64s of the shaft 64 and the inner circumferential surface 62s of the through hole 62, surrounding the entire outer circumferential surface 64s of the shaft 64.

[0043] As shown in FIG. 5A , at least a portion of the outer circumferential surface 64s of the shaft 64 or at least a portion of the inner circumferential surface 62s of the through-hole 62 may be provided with a substance that reduces the coefficient of friction (hereinafter also referred to as a “low-friction material 68”). In this embodiment, the low-friction material 68 is provided on at least an upper portion of the outer circumferential surface 64s of the shaft 64 or at least an upper portion of the inner circumferential surface 62s of the through-hole 62. When the low-friction material 68 is provided, the low-friction material 68 is provided on at least one of the outer circumferential surface 64s of the shaft 64 and the inner circumferential surface 62s of the through-hole 62. The low-friction material 68 may be provided on both the outer circumferential surface 64s of the shaft 64 and the inner circumferential surface 62s of the through-hole 62. Examples of the low-friction material 68 include coatings of fluorine-based resin, polyacetal, polyamide, and the like. The low-friction material 68 may be a lubricant such as grease.

[0044] This embodiment has the following advantages.

[0045] As shown in FIG. 1, the battery module 10 includes a detachment prevention mechanism 60 that prevents at least the heat exchanger 20 from falling off from the cell stack 12. With this configuration, even if vibrations exceeding expectations are applied to the battery module 10, the heat exchanger 20 is supported by the detachment prevention mechanism 60 (through-holes 62 and shafts 64) as shown in FIG. 5B. This prevents the heat exchanger 20 from falling off from the cell stack 12. Furthermore, since there is no need to increase the clamping force applied by the holding mechanism 17 (battery frame 16) shown in FIG. 1, it is possible to prevent the clamping force acting on the battery cells 18 from becoming too large when the battery cells 18 expand due to a temperature rise or deterioration of the battery cells 18.

[0046] 1, the anti-detachment mechanism 60 has a through-hole 62 formed in a portion of the heat exchanger 20 that does not overlap with the battery cells 18 in the stacking direction, and a shaft 64 that is inserted through the through-hole 62 and has both ends held. With this configuration, it is possible to effectively prevent the heat exchanger 20 from falling off from the cell stack 12 without affecting the battery cells 18.

[0047] The heat exchanger 20 is movable in the stacking direction relative to the shaft 64. With this configuration, it is possible to allow the heat exchanger 20 to move when the battery cells 18 expand due to heat generation or deterioration of the battery cells 18. This makes it possible to prevent the clamping force acting on the battery cells 18 from becoming too large.

[0048] When the cell stack 12 maintains its initial position, which is the position where it was initially pressed against the pressing portion 35, the entire circumference of the outer circumferential surface 64s of the shaft 64 is separated from the inner circumferential surface 62s of the through-hole 62, as shown in Fig. 5A. With this configuration, as long as the cell stack 12 maintains its initial position, when the battery cells 18 expand due to heat generation or deterioration of the battery cells 18 and the heat exchanger 20 moves relative to the shaft 64, no sliding resistance is generated between the heat exchanger 20 and the shaft 64. Therefore, the movement of the heat exchanger 20 is not hindered, and the function of absorbing the expansion of the battery cells 18 is properly exhibited.

[0049] A substance that reduces the coefficient of friction (low-friction material 68) is provided on at least a portion of the outer circumferential surface 64s of the shaft 64 or at least a portion of the inner circumferential surface 62s of the through hole 62. With this configuration, when the heat exchanger 20 moves relative to the shaft 64 in the stacking direction with the inner circumferential surface 62s of the through hole 62 in contact with the outer circumferential surface 64s of the shaft 64, if contact occurs at the position of the low-friction material 68, the sliding resistance between the heat exchanger 20 and the shaft 64 can be reduced.

[0050] A low-friction material 68 is provided on at least an upper portion of the outer peripheral surface 64s of the shaft 64 or at least an upper portion of the inner peripheral surface 62s of the through-hole 62. When the heat exchanger 20 is displaced downward due to an impact, the outer peripheral surface 64s of the shaft 64 and the inner peripheral surface 62s of the through-hole 62 come into contact with each other. Therefore, when the heat exchanger 20 moves relative to the shaft 64 in the stacking direction, the sliding resistance between the heat exchanger 20 and the shaft 64 can be reduced. Note that the low-friction material 68 does not necessarily have to be provided.

[0051] The through holes 62 are positioning holes for determining the installation position of the cell stack 12. With this configuration, the positioning holes can be used as anti-detachment holes, thereby streamlining the structure.

[0052] 2, the through holes 62 are formed in each of a pair of headers (the water supply / drainage header 26 and the turn header 28) in the heat exchanger 20. With this configuration, it is possible to effectively prevent the heat exchanger 20 from falling off from the cell stack 12 without increasing the number of components of the heat exchanger 20.

[0053] The following additional notes are further disclosed regarding the above embodiment.

[0054] (Appendix 1) The battery module (10) of the present disclosure comprises a cell stack (12) having battery cells (18) and a heat exchanger (20) stacked on the battery cells, a holding mechanism (17) that holds the cell stack by pressing both ends of the cell stack inward in the stacking direction, and a detachment prevention mechanism (60) that prevents at least the heat exchanger from falling off the cell stack.

[0055] (Appendix 2) In the battery module described in Appendix 1, the anti-detachment mechanism may have a through hole (62) formed in a portion of the heat exchanger that does not overlap with the battery cell in the stacking direction, and a shaft (64) that is inserted into the through hole and has both ends held, and the shaft may prevent the heat exchanger from falling off.

[0056] (Supplementary Note 3) In the battery module according to Supplementary Note 2, the shaft may extend in the stacking direction, and the heat exchanger may be movable relative to the shaft in the stacking direction.

[0057] (Appendix 4) In the battery module described in Appendix 3, the holding mechanism may have a pressing portion (35) that presses the cell stack, and when the cell stack is maintained in an initial position, which is the position at which it was initially pressed against the pressing portion, the entire circumference of the outer surface (64s) of the shaft may be separated from the inner surface (62s) of the through hole.

[0058] (Supplementary Note 5) In the battery module according to Supplementary Note 3, a substance that reduces a coefficient of friction may be provided on at least a part of an outer circumferential surface of the shaft or at least a part of an inner circumferential surface of the through hole.

[0059] (Supplementary Note 6) In the battery module according to Supplementary Note 5, the substance may be provided on at least an upper portion of the outer circumferential surface of the shaft or at least an upper portion of the inner circumferential surface of the through-hole.

[0060] (Supplementary Note 7) In the battery module according to Supplementary Note 2, the through-hole may be a positioning hole for determining an installation position of the cell stack.

[0061] (Appendix 8) In the battery module described in Appendix 2, a pair of headers may be provided at both ends of the heat exchanger in a horizontal direction perpendicular to the stacking direction, and the through hole may be formed in each of the pair of headers.

[0062] (Appendix 9) A battery module according to any one of Appendices 2 to 8, wherein the heat exchanger has a water jacket (24) extending in one direction, a water supply port (30) and a water drain port (32) provided at a first end which is one end of the water jacket in the longitudinal direction, and a turn header (28) provided at a second end which is the other end of the water jacket in the longitudinal direction, wherein the turn header receives cooling water from a forward flow path of the water jacket and directs the cooling water to a return flow path of the water jacket, and the through hole provided at the first end is circular, and the through hole provided at the second end may be in a track field shape with a major axis along the longitudinal direction of the water jacket.

[0063] (Supplementary Note 10) In the battery module described in Supplementary Note 9, the radius of the through hole provided at the first end and the radius of the semicircular arc portion (621) of the through hole provided at the second end may be approximately the same.

[0064] 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]

[0065] 10...Battery module 12...Cell stack 17...Retention mechanism 18...Battery cell 20...Heat exchanger 35...Pressing part 60… Falling prevention mechanism 62...Through hole 64...shaft

Claims

1. a cell stack including a battery cell and a heat exchanger stacked on the battery cell; a holding mechanism that holds the cell stack by pressing both end portions of the cell stack inward in the stacking direction; a fall-off prevention mechanism that prevents at least the heat exchanger from falling off from the cell stack.

2. The battery module according to claim 1, The fall-off prevention mechanism is a through hole formed in a portion of the heat exchanger that does not overlap with the battery cell in the stacking direction; a shaft that is inserted into the through hole and has both ends held; The shaft prevents the heat exchanger from falling off.

3. The battery module according to claim 2, The shaft extends in the stacking direction, The heat exchanger is movable relative to the shaft in the stacking direction.

4. The battery module according to claim 3, the holding mechanism has a pressing portion that presses the cell stack, A battery module in which, when the cell stack is maintained in an initial position, which is the initial position at which the pressing portion is pressed against the pressing portion, the entire circumference of the outer surface of the shaft is spaced apart from the inner surface of the through hole.

5. The battery module according to claim 3, A battery module, wherein a substance that reduces a friction coefficient is provided on at least a portion of an outer circumferential surface of the shaft or at least a portion of an inner circumferential surface of the through hole.

6. The battery module according to claim 5, The substance is provided on at least an upper portion of the outer circumferential surface of the shaft or at least an upper portion of the inner circumferential surface of the through hole.

7. The battery module according to claim 2, The through-hole is a positioning hole for determining an installation position of the cell stack.

8. The battery module according to claim 2, a pair of headers are provided at both ends of the heat exchanger in a horizontal direction perpendicular to the stacking direction, and the through hole is formed in each of the pair of headers;

9. The battery module according to any one of claims 2 to 8, The heat exchanger has a water jacket extending in one direction, a water supply port and a water discharge port provided at a first end portion which is one end portion of the water jacket in the longitudinal direction, and a turn header provided at a second end portion which is the other end portion of the water jacket in the longitudinal direction, the turn header receiving cooling water from a forward flow path of the water jacket and discharging the cooling water to a return flow path of the water jacket, The through hole provided in the first end portion is circular, The through hole provided at the second end has a track field shape with a major axis along the longitudinal direction of the water jacket.

10. The battery module according to claim 9, a radius of the through hole provided at the first end and a radius of the semicircular arc portion of the through hole provided at the second end are substantially the same.

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