Battery pack with battery modules

Abstract

To provide a battery pack having a reduced gross weight with a reduced manufacturing cost.SOLUTION: A battery pack 10 includes at least one set of battery modules 13. Each battery module 13 mainly includes: a battery stack 22 having a plurality of battery cells; a pair of side face plates 14 which covers both side faces of the battery stack 22 in the shorter direction; a pair of end plates 15 which covers both side faces of the battery stack 22 in the longer direction; and a bottom face plate 16 which covers the bottom face side of the battery stack 22. The above structure enables the layout change of the plurality of battery modules 13 according to the accommodation space of the battery pack 10 or the like. By the omission of the conventional battery case, the manufacturing cost is reduced and also, the gross weight is reduced.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery module in which the layout of a plurality of battery modules can be changed depending on the space of the installation location, and to a battery pack including the battery modules. [Background technology]

[0002] BACKGROUND ART As a conventional structure of a battery pack incorporating a plurality of battery modules, for example, the structure described in Patent Document 1 is known.

[0003] Battery packs are used in electric vehicles that require a large driving force, such as electric vehicles and hybrid vehicles. The battery pack includes a plurality of battery modules and a battery case that houses the plurality of battery modules spaced apart from one another. The battery case includes a tray member that secures each battery module and a cover member that covers the top of the tray member.

[0004] Furthermore, as a structure of a battery pack incorporating a conventional battery module, for example, the structure described in Patent Document 2 is known.

[0005] In order to improve the efficiency of mounting the battery modules in a vehicle, the battery pack has battery modules stacked in the vertical direction. In the battery pack, a mounting space for two battery modules is formed in the vertical direction by assembling a base frame, an intermediate frame, and a cover member. The battery modules are then housed in the mounting space and fixed by stack bolts provided on the frame. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-46211 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-99257 Summary of the Invention [Problem to be solved by the invention]

[0007] The battery pack described in Patent Document 1 has a battery case that houses multiple battery modules. The tray member of the battery case is made of sheet metal, and the battery modules are placed directly on the upper surface of the tray member. The tray member is provided with fixing portions for fixing the battery modules, and the battery modules are fixed to the fixing portions via brackets with bolts and nuts.

[0008] This structure requires a battery case to house the battery modules, which increases the manufacturing cost and weight of the battery pack. In addition, because the storage space for the battery pack and the number of battery modules used vary depending on the vehicle model, a battery case must be prepared for each vehicle model, making it difficult to reduce the manufacturing cost of the battery pack.

[0009] Furthermore, the battery pack described in Patent Document 2 has a frame for stacking and fixing the battery modules. This structure requires the frame to be separate from the battery modules, which makes it difficult to reduce manufacturing costs. Furthermore, due to the structure of the frame, there is also the problem that the frame cannot be used when fixing battery modules side by side in a battery pack.

[0010] The present invention has been made in view of the above circumstances, and relates to a battery module in which the layout of a plurality of battery modules can be changed depending on the space of the installation location, and a battery pack including the battery modules. [Means for solving the problem]

[0012] A battery pack including a battery module according to one embodiment of the present invention has a cover plate that covers the upper surface of the battery stack and is fixed to the first connecting protrusion, and the battery modules are stacked and fixed together by connecting the first connecting protrusion and the second connecting protrusion in the height direction of the battery stack, and are fixed side by side by connecting the cover plate and the first connecting protrusion. [Effects of the Invention]

[0014] A battery pack according to one embodiment of the present invention is configured to include at least one battery module. The battery pack also includes a cover plate that covers the top surfaces of the battery modules. This structure allows the layout of the multiple battery modules in the battery pack to be changed depending on the storage space available in the installation location of a vehicle or the like. Furthermore, by eliminating the need for a conventional battery case, manufacturing costs and the total weight are reduced. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram illustrating a vehicle equipped with a battery pack including a battery module according to an embodiment of the present invention. [Figure 2] 1 is a perspective view illustrating a battery module according to an embodiment of the present invention. [Figure 3] 1 is an exploded perspective view illustrating a battery module according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view illustrating a battery module according to an embodiment of the present invention. [Figure 5A] 1 is a perspective view illustrating a battery pack including a battery module according to an embodiment of the present invention. [Figure 5B] 1 is a perspective view illustrating a battery pack including a battery module according to an embodiment of the present invention. [Figure 5C] 1 is a perspective view illustrating a battery pack including a battery module according to an embodiment of the present invention. [Figure 5D]1 is a perspective view illustrating a battery pack including a battery module according to an embodiment of the present invention. [Figure 6A] 1 is a perspective view illustrating a battery module according to an embodiment of the present invention. [Figure 6B] 1 is a cross-sectional view illustrating a battery module according to an embodiment of the present invention. [Figure 6C] 1 is a cross-sectional view illustrating a battery module according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] A battery module 13 and a battery pack 10 including the battery module 13 according to one embodiment of the present invention will be described in detail below with reference to the drawings. In describing this embodiment, the same components will generally be designated by the same reference numerals, and repeated description will be omitted. The front-to-rear direction of the paper indicates the front-to-rear direction of the vehicle 11, the left-to-right direction of the paper indicates the width direction of the vehicle 11, and the up-to-down direction of the paper indicates the height direction of the vehicle 11.

[0017] FIG. 1 is a schematic diagram illustrating a vehicle 11 equipped with a battery pack 10 (see FIG. 2) according to this embodiment. FIG. 2 is a perspective view illustrating a battery module 13 of the battery pack 10 according to this embodiment. FIG. 3 is an exploded perspective view illustrating the battery module 13 of the battery pack 10 according to this embodiment. FIG. 4 is a cross-sectional view illustrating the battery module 13 of the battery pack 10 according to this embodiment, showing a cross section of the battery module 13 in the direction of line A-A in FIG. 2.

[0018] As shown in Fig. 1, a vehicle 11 such as an automobile or train is equipped with a battery pack 10 (see Fig. 2) for supplying power to a motor and various electrical components. In the case of automobiles as the vehicle 11, EVs (Electrical Vehicles), HEVs (Hybrid Electrical Vehicles), PHEVs (Plug-in Hybrid Electrical Vehicles), and the like have become widespread in recent years.

[0019] The battery pack 10 is disposed, for example, in a storage space 12 below the rear floor at the rear of the vehicle 11, with the longitudinal direction of the battery pack 10 coinciding with the left-right direction of the vehicle 11. The battery pack 10 is not limited to being disposed in the storage space 12 below the rear floor, but may also be disposed in a storage space below the front floor or the like where the driver's seat and passenger seat of the vehicle 11 are located. Depending on the storage space 12, the longitudinal direction of the battery pack 10 may also coincide with the front-to-rear direction of the vehicle 11.

[0020] As shown in Fig. 2, the battery pack 10 is configured to include at least one battery module 13. When multiple battery modules 13 are used as the battery pack 10 depending on the amount of power supply in the vehicle 11, the battery pack 10 uses the multiple battery modules 13 connected in series or parallel, or a combination of series and parallel connections. When the battery pack 10 is attached to the vehicle 11, cover plates 31 and 33 shown in Figs. 5A to 5D are used.

[0021] The battery module 13 mainly comprises a battery stack 22 composed of a plurality of battery cells 21 (see FIG. 3), a pair of side plates 14 covering both side surfaces of the battery stack 22 in the short direction (front-to-back direction on the paper), a pair of end plates 15 covering both side surfaces of the battery stack 22 in the long direction (left-to-right direction on the paper), and a bottom plate 16 covering the bottom side of the battery stack 22.

[0022] Although not shown, bus bars that connect to the battery stack 22, insulating covers that cover the bus bars, and the like are arranged on the upper surface of the battery module 13. The battery module 13 is also electrically connected to a BCU (Battery Control Unit) and a junction box, which are electronic devices.

[0023] As shown in FIG. 3 , the battery stack 22 is placed on the upper surface of the bottom plate 16, and multiple battery cells 21 are connected in series via bus bars (not shown). The battery cells 21 are, for example, secondary batteries such as nickel-metal hydride batteries or lithium-ion batteries. The individual battery cells 21 have, for example, a rectangular flat plate shape and are arranged at equal intervals along the longitudinal direction of the battery stack 22 (the left-right direction on the page) with small cooling gaps 46 (see FIG. 6B ) in front and behind them. In the description of this embodiment, the first direction described in the claims corresponds to the arrangement direction of the battery cells 21, and the second direction described in the claims corresponds to the direction perpendicular to the arrangement direction of the battery cells 21.

[0024] The side plate 14 is formed, for example, from an extruded aluminum material. The side plate 14 is disposed along the longitudinal direction of the battery stack 22. The side plate 14 has a plate-shaped portion 14A that covers the side of the battery stack 22, and a first connecting protrusion 14B formed on the upper portion of the plate-shaped portion 14A.

[0025] When the battery pack 10 is configured by electrically connecting multiple battery modules 13, the first connecting protrusion 14B is used as a member for stacking and fixing the battery modules 13 together or arranging them side by side. The plate-like portion 14A is formed with multiple connecting holes 14C for connecting the battery modules 13 to the end plates 15 and the bottom plate 16 via rivets 23, 24, for example. Meanwhile, the first connecting protrusion 14B is formed with two types of connecting holes 14D, 14E.

[0026] A plurality of connecting holes 14D are formed on the upper surface of the first connecting protrusion 14B. The first connecting protrusion 14B is connected to the cover plates 31 and 33 (see FIGS. 5A and 5B) via the connecting holes 14D using bolts and nuts. Meanwhile, a plurality of connecting holes 14E are formed on the side surface of the first connecting protrusion 14B. When the battery modules 13 are stacked and fixed together, the first connecting protrusion 14B is connected to the bottom plate 16 of another battery module 13 via the connecting holes 14E using bolts and nuts.

[0027] The bottom plate 16 is formed, for example, from extruded aluminum. The bottom plate 16 is disposed along the longitudinal direction (left-right direction on the page) of the battery stack 22. The bottom plate 16 has a mounting portion 16A on which the battery stack 22 is mounted, and second connecting protrusions 16B formed on both ends of the mounting portion 16A.

[0028] When the battery pack 10 is configured by electrically connecting a plurality of battery modules 13, the second connecting protrusion 16B is used as a member for stacking and fixing the battery modules 13. Two types of connecting holes 16C and 16D are formed on the side surface of the second connecting protrusion 16B.

[0029] The plurality of connecting holes 16C are formed on the upper side of the second connecting protrusion 16B. The second connecting protrusion 16B is connected to a side plate 14 constituting the same battery module 13 via the connecting holes 16C, for example, by rivets 24. On the other hand, the plurality of connecting holes 16D are formed on the lower side of the second connecting protrusion 16B. When the battery modules 13 are stacked and fixed together, the second connecting protrusion 16B is connected to a side plate 14 constituting another battery module 13 via the connecting holes 16D, for example, by using bolts and nuts.

[0030] The end plates 15 are formed, for example, by bending a steel plate. The end plates 15 are members that cover the front and rear end faces in the longitudinal direction of the battery stack 22. As will be described in detail later, the end plate 15 on the front end side (left side of the drawing) is formed with an intake port 42 that constitutes a cooling mechanism 41 (see FIG. 6A) for the battery module 13, and the end plate 15 on the rear end side (right side of the drawing) is formed with an exhaust port 43 (see FIG. 6A) that constitutes a cooling mechanism 41 for the battery module 13.

[0031] The separators 25 are disposed between the end plates 15 and the battery stack 22 and between each battery cell 21. The separators 25 are insulating members formed, for example, by resin molding. The separators 25 are members that fix the positions of the multiple battery cells 21 inside and support the battery stack 22. The separators 25 are fixed in position to the bottom plate 16, and thus the battery stack 22 is also fixed to the bottom plate 16. The separators 25 are fixed in a state where they are sandwiched between the first connecting protrusion 14B and the mounting portion 16A of the side plate 14, as will be described in detail later.

[0032] 4, the first connecting protrusion 14B of the side plate 14 is formed as a hollow skeleton frame having a generally square cross section, and is disposed above both ends of the battery stack 22 in the short side direction (front-to-back direction on the paper), and is also disposed across the battery stack 22 in the long side direction (left-to-right direction on the paper).

[0033] On the other hand, the second connecting protrusions 16B of the bottom plate 16 are formed as a hollow skeleton frame with a generally square cross section. They are disposed below both ends of the battery stack 22 in the short side direction (front-to-back direction on the paper) and are disposed across the battery stack 22 in the long side direction (left-to-right direction on the paper). Parts of the second connecting protrusions 16B extend downward from the battery module 13.

[0034] As shown, the side plate 14 and the bottom plate 16 are connected to each other by rivets 24 through connecting holes 14C and 16C (see FIG. 3). On the other hand, the side plate 14 and the end plate 15 are connected to each other by rivets 23 through connecting holes 14C and 15A (see FIG. 3).

[0035] With this structure, the side plates 14, end plates 15, and bottom plate 16 are connected to one another via rivets 23, 24, forming a box-shaped storage and protection frame that houses the battery stack 22. After the battery pack 10 is attached to the body of the vehicle 11, the battery stack 22 is prevented from coming into direct contact with the body of the vehicle 11 due to vibrations of the vehicle 11, and damage to the battery cells 21 can be prevented.

[0036] Furthermore, as described above, the first and second connecting protrusions 14B, 16B are arranged along the longitudinal direction of the battery stack 22 (left-right direction on the paper) at the four corners of the storage and protection frame, and function as a skeletal frame.

[0037] As a result, for example, if a collision occurs from behind the vehicle 11, a large impact is applied to the rear of the vehicle 11, causing the rear bumper 11B (see FIG. 1) to move inward toward the inside of the vehicle 11. At this time, the first and second connecting protrusions 14B, 16B absorb the impact, thereby preventing damage to the battery cells 21 that make up the battery stack 22.

[0038] That is, when the battery module 13 is attached to the vehicle 11, it does not require a conventional battery case, but is protected by the storage protection frame composed of the side plates 14, end plates 15, and bottom plate 16. Eliminating the need for a conventional battery case reduces the manufacturing cost and weight of the battery pack 10. Furthermore, eliminating the need for a conventional battery case also eliminates the need for a bracket to attach the battery module 13 to the battery case.

[0039] As described above, the side plates 14 are formed integrally from an extruded material, and their longitudinal lengths are adjusted according to the length of the battery stack 22. Similarly, the bottom plate 16 is also formed integrally from an extruded material, and their longitudinal lengths are adjusted according to the length of the battery stack 22. As a result, the shapes of the side plates 14 and bottom plate 16 can be easily changed according to the length of the battery stack 22, etc., and it is no longer necessary to prepare them for each vehicle model, as is the case with conventional battery cases, thereby reducing manufacturing costs.

[0040] 5A to 5D are perspective views illustrating the battery pack 10 of this embodiment. Fig. 5A and Fig. 5B show the battery pack 10 composed of two battery modules 13. On the other hand, Fig. 5C and Fig. 5D show the battery pack 10 composed of four battery modules 13.

[0041] In the battery pack 10 shown in Fig. 5A, two battery modules 13 are arranged side by side in their longitudinal direction (left-right direction on the paper) and fixed in a flat state using a cover plate 31. The cover plate 31 is formed, for example, from resin or steel plate. As described above, the cover plate 31 is connected to the first connecting protrusion 14B (see Fig. 3) of the side plate 14 using bolts and nuts via connecting holes 14D and 14E (see Fig. 3). Therefore, connecting holes 31A and 31B corresponding to connecting holes 14D and 14E (see Fig. 3) are formed in the cover plate 31 along its longitudinal direction.

[0042] As shown in the figure, the cover plate 31 is formed to be longer in its longitudinal direction (left-right direction on the paper) than the battery stack 22. Both ends of the cover plate 31 are provided with vehicle body fixing portions 32 that are attached to the body of the vehicle 11.

[0043] With this structure, the vehicle body fixing portion 32 of the cover plate 31 is fixed to the body of the vehicle 11 using bolts and nuts, thereby fixing the battery pack 10 to the vehicle 11. As described above, by fixing the cover plate 31 to the first connecting protrusion 14B, which serves as a skeletal frame, vibrations and the like caused when the vehicle 11 is traveling are alleviated, and collisions between the battery cells 21 are prevented.

[0044] 5B, two battery modules 13 are arranged side by side in the short-side direction (front-to-back direction on the paper) and fixed in a flat state using a cover plate 33. Similar to the cover plate 31 described above, the cover plate 33 has connecting holes 33A and 33B formed at positions corresponding to the connecting holes 14D and 14E (see FIG. 3) of the first connecting protrusion 14B (see FIG. 3).

[0045] As shown in the figure, the battery pack 10 can accommodate a storage space 12 (see FIG. 1) of a vehicle 11 by changing the connection direction of the battery modules 13. The battery pack 10 is fixed to the body of the vehicle 11 via the body fixing portion 34 of the cover plate 33 using bolts and nuts.

[0046] The battery pack 10 shown in Fig. 5C is configured by four battery modules 13, which are stacked and fixed in two stages and then arranged side by side in the longitudinal direction (left-right direction on the paper). In this structure, the cover plate 31 shown in Fig. 5A is used, and the cover plate 31 is fixed to the first connecting protrusion 14B (see Fig. 3) of the battery module 13 located in the upper stage. The battery pack 10 is then fixed to the body of the vehicle 11 via the body fixing portion 32 of the cover plate 31 using bolts and nuts.

[0047] The battery pack 10 shown in Fig. 5D is configured with four battery modules 13, each of which is stacked and fixed in two stages and then arranged side by side in the short direction (front-to-back direction on the page). In this structure, a cover plate 33 shown in Fig. 5B is used, and the cover plate 33 is fixed to the first connecting protrusion 14B (see Fig. 3) of the battery module 13 located in the upper stage. The battery pack 10 is then fixed to the body of the vehicle 11 via the body fixing portion 34 of the cover plate 33 using bolts and nuts.

[0048] Next, Fig. 6A is a perspective view illustrating the cooling mechanism 41 of the battery pack 10 of this embodiment. Fig. 6B is a cross-sectional view illustrating the cooling mechanism 41 of the battery pack 10 of this embodiment. Fig. 6C is a cross-sectional view illustrating the cooling mechanism 41 and assembly structure of the battery pack 10 of this embodiment. For convenience of explanation, Fig. 6A shows the end plate 15 disassembled from the side plate 14.

[0049] 6A, a battery module 13 of a battery pack 10 is provided with a cooling mechanism 41 for cooling the battery cells 21 arranged therein. The cooling mechanism 41 mainly includes an intake port 42 formed in the end plate 15 on the front end side (left side of the drawing), an exhaust port 43 formed in the end plate 15 on the rear end side (right side of the drawing), a cooling air passage 44 communicating with the intake port 42, a cooling air passage 45 communicating with the exhaust port 43, a cooling gap 46 (see FIG. 6B) connecting the cooling air passages 44 and 45, and a cooling duct (not shown) communicating with the intake port 42. In the description of this embodiment, a first cooling air passage described in the claims corresponds to the cooling air passage 44, and a second cooling air passage described in the claims corresponds to the cooling air passage 45.

[0050] As shown, an air intake 42 is formed in the end plate 15 located upstream of the cooling mechanism 41. Although not shown, a cooling duct that communicates with an air conditioning mechanism (not shown) of the vehicle 11 is connected to the air intake 42 in the end plate 15, and cooling air generated by the air conditioning mechanism is sent into the battery module 13 through the air intake 42.

[0051] 6B , inside the battery module 13, the side plates 14 are disposed at a distance from the sides of the battery stack 22, thereby forming cooling air passages 44, 45 between the side plates 14 and the battery stack 22. As described above, the battery cells 21 constituting the battery stack 22 are arranged with cooling gaps 46 in the longitudinal direction of the battery stack 22 (the left-right direction on the page).

[0052] 6C, the side plate 14 has a structure in which the upper side of the plate-like portion 14A and the first connecting protrusion 14B press against and secure the upper corner of the separator 25 (see FIG. 3). Meanwhile, the bottom plate 16 has a structure in which the second connecting protrusion 16B positions the lower corner of the separator 25. With this structure, the separator 25 is fixed in a state in which it is pressed against the bottom plate 16 by the side plate 14. Even if vibrations occur while the vehicle 11 is running or an impact occurs due to a vehicle collision, this structure prevents the separator 25 from shifting, preventing the battery stack 22 from colliding with surrounding components and damaging the battery cells 21.

[0053] Cooling air passages 44, 45 are formed between the side plate 14 and the battery stack 22 by utilizing the structure in which the separator 25 is fixed by the side plate 14.

[0054] With this structure, as shown by arrow 48, cooling air sent from intake port 42 through the cooling duct to cooling air passage 44 flows to end plate 15 on the opposite side, passes through cooling gap 46, and flows into cooling air passage 45. The cooling air flowing through cooling air passage 45 is then discharged to the outside of battery module 13 from exhaust port 43 in end plate 15.

[0055] The cooling air cools the battery cells 21 from the sides as it flows through the cooling air passages 44, 45, and in particular cools the battery cells 21 from their front and back as it flows through the cooling gaps 46, preventing the battery cells 21 from overheating.

[0056] As described above with reference to Figures 5A to 5D, when the battery pack 10 is attached to the vehicle body, the upper surface of the battery stack 22 is covered with cover plates 31, 33 (see Figures 5A and 5B), which makes it difficult for cooling air to leak from the cooling gap 46 to the outside of the battery module 13. [Explanation of symbols]

[0057] 10 Battery pack 11 vehicles 13 Battery module 14 Side Plate 14A Plate-shaped part 14B First connecting protrusion 14C,14D,14E,15A,16C,16D connection hole 15 End Plate 16 Bottom plate 16A Placement section 16B Second connecting protrusion 21 Battery Cells 22 Battery stack 25 Separator 31,33 Cover plate 32,34 Body fixing part 41 Cooling mechanism 42 Air intake 43 Exhaust port 44,45 Cooling air passage 46 Cooling gap

Claims

1. A battery pack comprising a battery module having a battery stack in which a plurality of battery cells are arranged in a first direction, a cover plate covering an upper surface of the battery stack; The battery module includes: a bottom plate covering the lower surface of the battery stack; side plates covering both end portions of the battery stack in a second direction perpendicular to the first direction; end plates covering both end portions of the battery stack in the first direction; a first connecting protrusion formed on the side plate and protruding upward from the battery stack; a second connecting protrusion formed on the bottom plate and protruding downward from the battery stack; The battery modules are stacked and fixed together by connecting the first connecting protrusion and the second connecting protrusion in the height direction of the battery stack, and are fixed side by side by connecting the cover plate and the first connecting protrusion.

2. 2. The battery pack according to claim 1, wherein the side plates and the bottom plate are each formed from an extruded material.

3. the side plate is fixed to the bottom plate in a state in which a first cooling air passage and a second cooling air passage extending in the first direction are formed between the side plate and the battery stack; an intake port communicating with the first cooling air passage and an exhaust port communicating with the second cooling air passage are formed in the end plate; 3. The battery pack including the battery module according to claim 1, wherein a cooling gap communicating with the first cooling air passage and the second cooling air passage is formed between the battery cells adjacent in the first direction.

4. the cover plate has a vehicle body fixing portion that extends outward beyond the battery stack, 4. A battery pack including the battery module according to claim 1, wherein the vehicle body fixing portion is fixed to the vehicle body.

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