Battery pack

Abstract

To provide a battery pack which can achieve improvement of loading efficiency of the battery module, while inhibiting increase of weight of the battery module and inhibit thermal chain when thermal runaway of a battery cell occurs.SOLUTION: A battery pack includes a case, a battery module disposed in the case, and a cover covering an upper side of the battery module. The battery module includes: a laminated body in which a plurality of secondary batteries is laminated; and side restraint members each facing a first surface of the laminated body and extending in a lamination direction of the laminated body. The first surface is a surface arranged in a direction perpendicular to a lower surface of the laminated body and along the lamination direction. A first distance between an upper end of the side restraint member and the cover is shorter than a second distance between an upper surface of the laminated body and the cover.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] In recent years, research and development into secondary batteries that contribute to energy efficiency has been conducted in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Patent Document 1 discloses a battery module configuration including a stack of multiple battery cells (secondary batteries), a pair of bind bars, and a pair of end plates. The pair of bind bars are members that restrain the stacking direction of the multiple battery cells, and the pair of end plates are members that restrain the width direction of the battery cells (a direction intersecting the stacking direction). The pair of bind bars and the pair of end plates are components that are primarily intended to hold and protect the stack of multiple battery cells.

[0004] A battery pack is formed by mounting (arranging) multiple battery modules in a housing (case) that protects them from external forces. The housing of the battery pack is provided with structural members such as cross members and side frames to ensure strength and rigidity, resistance to external forces, and to connect to the vehicle.

[0005] The cross member is a structural member extending in the stacking direction of the battery cells in the housing, and extends in the same direction as the bind bar that restrains the battery cells in the stacking direction. The side frame is a structural member extending in the arrangement direction of the battery cells in the housing (a direction intersecting the stacking direction), and extends in the same direction as the end plates that restrain the battery cells in the width direction.

[0006] The cross members and side frames contribute to the strength and rigidity of the battery pack housing in the fore-and-aft and left-right directions of the vehicle, as well as resistance to external forces, and the cross members and side frames hold and protect multiple battery modules within the housing. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2019 / 167689 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the structural members (cross members, side frames) provided on the housing and the structural members (bind bars, end plates) that make up the battery module are provided independently, which can be inefficient in terms of cost, weight, and securing space for mounting the battery module in the housing.

[0009] When attempting to secure strength, rigidity, and resistance to external forces by fixing the battery modules with bind bars and end plates and holding multiple battery modules with cross members and side frames, the weight of the battery modules increases, so it is necessary to suppress this weight increase.

[0010] In addition, because the structural members (bind bars, end plates) constituting the battery module and the structural members (cross members, side frames) provided on the housing (hereinafter also referred to as the case) partially occupy the mounting space for the battery cells within the case, it is required to improve the mounting efficiency of the battery module including the secondary battery. Also, in a battery pack including multiple battery modules, it is required to suppress thermal chain reaction when the battery cells experience thermal runaway. [Means for solving the problem]

[0011] In consideration of the above problems, the present application provides a battery pack that can suppress thermal chain reactions when a battery cell experiences thermal runaway in a battery module that can improve mounting efficiency while suppressing an increase in the weight of the battery module.

[0012] A battery pack according to one aspect of the present invention includes a case, a battery module disposed in the case, and a cover covering an upper portion of the battery module, The battery module includes: A stack of a plurality of secondary batteries; a side restraining member facing the first surface of the laminate and extending in the laminate direction, The first surface is a surface that is perpendicular to the lower surface of the stack and aligned along the stacking direction, The first distance between the upper end of the side restraint member and the cover is shorter than a second distance between the upper surface of the stack and the cover. Effect of the Invention

[0013] According to the present invention, a battery pack can be provided that can suppress thermal chain reactions when a battery cell experiences thermal runaway in a battery module that can improve mounting efficiency while suppressing an increase in the weight of the battery module. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram for explaining a schematic configuration of a battery module and a battery module group according to an embodiment; [Diagram 2] 5A to 5C are diagrams illustrating a joining structure between a battery cell and a side restraint member according to an embodiment. [Diagram 3] 4A and 4B are diagrams illustrating a structure in which a battery module group is arranged in a case according to an embodiment. [Figure 4] 1A and 1B are diagrams illustrating a first example of a connecting structure for connecting end restraint members according to an embodiment. [Diagram 5]13A and 13B are diagrams illustrating a second example of a connecting structure for connecting end restraint members according to an embodiment. [Figure 6] 13A and 13B are diagrams illustrating a third example of a connecting structure for connecting end restraint members according to an embodiment. [Figure 7] 1 is a diagram illustrating a cross-sectional structure of a battery cell according to an embodiment; [Figure 8] 11A and 11B are diagrams illustrating a thermal chain reaction prevention structure of a battery pack according to a second embodiment. [Figure 9] 13A and 13B are diagrams illustrating a thermal chain reaction prevention structure of a battery pack according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0016] [Embodiment] <Battery module 110, battery module group 115> FIG. 1 is a diagram for explaining the schematic configuration of a battery module 110 and a battery module group 115 according to the embodiment.

[0017] 1A, a plurality of battery cells 100 (secondary batteries) are arranged in the X direction (stacking direction), and a stack 111 is formed by stacking the plurality of battery cells 100. A heat insulating material (not shown) may be arranged between the battery cells 100 arranged in the X direction.

[0018] 1, the X direction (stacking direction) of the laminate 111 is defined as a first direction. Also, a direction (Y direction) intersecting with a surface (XZ surface: first surface 101) of the multiple battery cells 100, i.e., a surface (XZ surface: first surface 101) of the battery module 110 (laminated body 111) is defined as a second direction (intersecting direction). A direction intersecting with the first direction and the second direction is defined as a third direction (vertical direction).

[0019] In addition, the surface of the battery cell 100 in the X direction and the Z direction (XZ surface) and the surface of the battery module 110 (laminated body 111) in the X direction and the Z direction (XZ surface) are defined as first surfaces 101, and the surface of the battery cell 100 in the Y direction and the Z direction (YZ surface) and the surface of the battery module 110 (laminated body 111) in the Y direction and the Z direction (YZ surface) are defined as second surfaces 102.

[0020] The first surface 101 is a surface that is perpendicular to the lower surface (XY plane) of the battery module 110 (laminated body 111) and is aligned along the lamination direction. The second surface 102 is a surface that is perpendicular to the lower surface (XY plane) of the battery module 110 (laminated body 111) and intersects with the lamination direction. Here, the lower surface (XY plane) of the laminated body 111 is a surface on which the laminated body 111 is placed in the case 400 (battery case: FIG. 3).

[0021] The surface (XZ surface) of the battery module 110 (laminated body 111) is a surface formed by the surfaces (XZ surface: first surface 101) of the multiple battery cells 100. The surface (YZ surface) of the battery module 110 (laminated body 111) is a surface (YZ surface: second surface 102) in the Y and Z directions of the battery cell 100 arranged at the end among the multiple battery cells 100 constituting the laminated body 111.

[0022] As shown in FIG. 1B, the side restraint members 200 (200a, 200b) face the first surface 101 (XZ surface) of the battery module 110 (stacked body 111) and extend in the X direction (stacking direction) of the stacked body 111.

[0023] The first surface 101 (XZ surface) of each battery cell 100 constituting the stack 111 and the side restraint members 200 (200a, 200b) are joined by a joining member.

[0024] 2 is a diagram illustrating a bonding structure between the battery cell 100 and the side restraint member 200. FIG. 2 is a diagram of the battery cell 100 as viewed from the YZ plane (second surface 102), and an insulating film 702 is provided between a bonding member 701 (for example, an adhesive or double-sided tape) and the battery cell 100. The insulating film 702 is provided so as to cover the interface with the bonding member 701 as well as parts of the lower and upper surfaces of the battery cell 100. The type of insulating film 702 is not particularly limited, and may be a resin material. The resin material may include, for example, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and the like.

[0025] The gap between the battery cell 100 and the case 400 (battery case) is filled with a filler 703. The type of filler 703 is not particularly limited, and may be a resin material. The insulating film 702 and the filler 703 may be made of a flame-retardant material so as to be able to withstand exposure to high temperatures due to thermal runaway of the battery cell 100.

[0026] When an adhesive is used as the joining member 701, the adhesive may be filled between the first surface 101 (XZ surface) and the side restraint member 200 to join them. The type of adhesive is not particularly limited, and examples thereof include acrylic resin, urethane resin, silicon resin, epoxy resin, and olefin resin.

[0027] In a side view of the YZ plane (second surface 102), the side restraint member 200 joined to the left side of the battery cell 100 on the page is referred to as side restraint member 200 (200a). Additionally, the side restraint member 200 joined to the right side of the battery cell 100 on the page is referred to as side restraint member 200 (200b). The terms "side restraint member 200" or "side restraint member 200 (200a, 200b)" refer collectively to the side restraint member 200 (200a) and the side restraint member 200 (200b).

[0028] Moreover, the first surface 101 (XZ surface) of the battery cell 100 on the left side of the paper surface will be referred to as the first surface 101 (101a), and the first surface 101 (XZ surface) of the battery cell 100 on the left side of the paper surface will be referred to as the first surface 101 (101b). The term "first surface 101" or "first surface 101 (XZ surface)" collectively refers to the first surface 101 (101a) and the first surface 101 (101b).

[0029] The first surface 101 (101a) and the first surface 101 (101b) of the battery cell 100 have a similar junction structure.

[0030] 2, the battery cell 100 shown in dashed lines indicates another battery cell 100 arranged adjacent to the battery cell 100 shown in solid lines along the Y direction. The side restraint member 200 (200b) shown in dashed lines is joined to the battery cell 100 by a joining structure similar to that of the side restraint member 200 (200a).

[0031] In FIG. 2, the side restraint member 200 (200a) faces the first surface 101 (101a) at one end in the Y direction, and the side restraint member 200 (200b) faces the first surface 101 (101b) at the other end in the Y direction.

[0032] The side restraint members 200 (200a, 200b) are plate-like members made of metal such as aluminum, aluminum alloy, copper, iron, iron alloy, stainless steel, etc. The shape of the side restraint members 200 (200a, 200b) is not particularly limited as long as they can hold and restrain the first faces 101 (101a, 101b: XZ faces) of each battery cell 100 constituting the battery module 110 (stacked body 111).

[0033] As shown in Figure 1B and Figure 2, in a side view of the YZ plane (second surface 102), a pair of side restraint members 200 (200a, 200b) face the first surface 101 (101a) at one end side in the Y direction of the YZ plane (second surface 102) of the laminate 111 (battery cell 100) and the first surface 101 (101b) at the other end side in the Y direction, and extend in the stacking direction of the laminate 111 (battery cell 100).

[0034] The side restraint members 200 (200a, 200b) hold and restrain the stacking direction (X direction: first direction) of the battery module 110 (stacked body 111), and can also function as members that provide strength and rigidity to the battery module 110 (stacked body 111) and protect the battery module 110.

[0035] As shown in FIG. 1C, the battery modules 110 (stack 111) are arranged in a case (400 in FIG. 3) in which the battery modules 110 (stack 111) are arranged in a second direction (Y direction) that is vertical to the underside of the stack 111 and intersects the stacking direction.

[0036] The side restraint members 200 (200a, 200b) face, in the second direction, the side restraint members 200 of another battery module 110 arranged adjacently inside the case (400 in FIG. 3).

[0037] For example, among multiple battery modules 110, the side restraint member 200 (e.g., solid line in Figure 2) of one battery module 110 and the side restraint member 200 (e.g., dashed line in Figure 2) of another battery module 110 arranged adjacently along the second direction (Y direction) are arranged in the case 400 facing each other in the second direction.

[0038] As shown in FIG. 1D, the battery module 110 further includes an end restraint member 300 that holds the YZ surface (second surface 102) of the battery module 110 (laminated body 111) and is connected to the side restraint member 200.

[0039] 1D, in a side view of the XZ plane (first surface 101), the end restraint member 300 on the right side of the battery module 110 in the paper is referred to as end restraint member 300 (300a). Also, the end restraint member 300 on the left side of the battery module 110 in the paper is referred to as end restraint member 300 (300b). The notation "end restraint member 300" or "end restraint member 300 (300a, 300b)" refers collectively to the end restraint member 300 (300a) and the end restraint member 300 (300b).

[0040] Moreover, the end restraint member 300 of each battery module 110 is connected along the second direction (Y direction) to the end restraint member 300 of another adjacent battery module 110 to form a long end restraint member 310. The long end restraint member 310 on the right side of the battery module 110 on the page is referred to as the long end restraint member 310 (310a). The long end restraint member 310 on the left side of the battery module 110 on the page is referred to as the long end restraint member 310 (310b). The term "long end restraint member 310" or "long end restraint member 310 (310a, 310b)" refers collectively to the long end restraint member 310 (310a) and the long end restraint member 310 (310b).

[0041] In addition, in a side view of the XZ plane (first surface 101), the second surface 102 (YZ surface) at one end side in the X direction of the battery module 110 is referred to as the second surface 102 (102a), and the second surface 102 (YZ surface) at the other end side in the X direction is referred to as the second surface 102 (102b). The term "second surface 102 (YZ surface)" or "second surface 102 (102a, 102b)" collectively refers to the second surface 102 (102a) and the second surface 102 (102b).

[0042] The end restraint member 300 is a plate-like member made of metal such as aluminum, an aluminum alloy, copper, iron, an iron alloy, stainless steel, etc. The shape of the end restraint member 300 is not particularly limited as long as it can hold and restrain the second surface 102 (YZ surface) of the battery module 110 (stacked body 111).

[0043] 1D, in a side view in the XZ plane direction, a pair of end restraint members 300 (300a, 300b) extend opposite the second surface 102 (102a) at one end side in the X direction of the battery module 110 and the second surface 102 (102b) at the other end side in the X direction. That is, the end restraint member 300 (300a) faces the second surface 102 (102a) at one end side in the X direction, and the end restraint member 300 (300b) faces the second surface 102 (102b) at the other end side in the X direction.

[0044] The end restraint member 300 holds and restrains the arrangement direction (Y direction: second direction) of the battery module 110 (stacked body 111), and can also function as a member that provides strength and rigidity to the battery module 110 (stacked body 111) and protects the battery module 110.

[0045] The end restraint members 300 (300a, 300b) of each battery module 110 are connected and extended along the second direction (Y direction). The end restraint members 300 (300a, 300b) connected along the second direction (Y direction) are configured as long end restraint members 310 (310a, 310b). The long end restraint members 310 (310a, 310b) hold and restrain the arrangement direction (Y direction: second direction) of the assembly of the multiple battery modules 110 (battery module group 115), and can provide strength and rigidity to the battery module group 115 and function as a member that protects the battery module group 115. A connection structure for connecting the end restraint members 300 will be described with reference to FIGS. 4 to 6.

[0046] FIG. 1E illustrates an assembly (battery module group 115) of the battery modules 110 arranged in an arrangement direction (Y direction: second direction).

[0047] 1E in which six battery modules 110 are arranged, any number of battery modules 110 may be included in the battery module group 115. Electrical components 116 are attached to each of the battery modules 110 that make up the battery module group 115. The electrical components 116 include, for example, conductive members (bus bars) that electrically connect terminals between the battery cells 100 that make up the stack 111, voltage detection lines that detect voltages from each battery cell 100, and the like.

[0048] In the battery module group 115, the side restraint members 200 (200a, 200b) of each battery module 110 hold and restrain the stacking direction (X direction: first direction) of the battery module 110 (stacked body 111), and can also function as members that provide strength and rigidity to the battery module 110 (stacked body 111) and protect the battery module 110. That is, in the battery module group 115 composed of a plurality of battery modules 110, the side restraint members 200 (200a, 200b) have a function that integrates the cross member of a housing (case) in the conventional technology and the bind bar that constitutes a battery module.

[0049] In the prior art, the functions performed by the cross member of the housing (case) and the functions performed by the bind bar can be consolidated into the side restraint member 200 (200a, 200b) in the battery module 110 and battery module group 115 of this embodiment.

[0050] In addition, the long end restraint members 310 (310a, 310b) hold the arrangement direction (Y direction: second direction) of the collection of multiple battery modules 110 (battery module group 115), restrain the battery module group 115, and also provide strength and rigidity to the battery module group 115, and can function as a member to protect the battery module group 115.

[0051] The long end restraint members 310 (310a, 310b) have a function that integrates the side frame of a housing (case) in the conventional technology and the end plate that constitutes a battery module.

[0052] In the battery module 110 and the battery module group 115 of the present embodiment, the functions that were performed by the side frames of the housing (case) and the functions that were performed by the end plates in the conventional technology can be integrated into the end restraint members 300 (300a, 300b) and the long end restraint members 310 (310a, 310b). As a result, the battery module 110 and the battery module group 115 composed of the multiple battery modules 110 have sufficient strength and rigidity.

[0053] <Battery Pack 500> A battery pack 500 is configured by mounting (arranging) a plurality of battery modules 110 (battery module group 115) in a case 400 for protecting the battery modules 110 from external forces and covering the upper side with a cover 410. The battery pack 500 can be mounted, for example, in an electric vehicle such as a hybrid car or an EV (not shown).

[0054] 3 is a diagram illustrating a structure in which the battery module group 115 is arranged in the case 400 (battery case). The case 400 is a tray-shaped case, and the bottom plate of the case 400 can be made of a material that has insulating properties and excellent thermal conductivity. The fastening member 460 is a member for fixing the battery module group 115 to the case 400, and includes, for example, a fastening bolt.

[0055] 1 are formed with holes (through holes) through which fastening members 460 for fixing the battery module group 115 to the case 400 can pass. The case 400 is formed with, for example, a screw portion (e.g., a female screw) that screws with the fastening member 460 (e.g., a fastening bolt). Attached to the case 400 are a control unit 420 that controls the power supplied from the battery module group 115, and an interface section 430 that includes a connector for connecting to an external device, etc.

[0056] A frame 450 for reinforcing the case 400 is attached to the lower surface of the case 400. The frame 450 is a member extending along one side of the case 400 (for example, the side in the Y direction in FIG. 2). The frame 450 contributes to improving the strength and rigidity of the case 400. In order to reduce the weight of the battery pack 500, the frame 450 may have a substantially hollow structure in which a reinforcing portion 455 such as a rib is formed upward with respect to the extending direction (for example, the Z direction in FIG. 2). The number of the reinforcing portions 455 is not particularly limited, and it is sufficient that at least one reinforcing portion 455 is formed. In addition, in the example of FIG. 2, the frame 450 is extended along the Y direction of the case 400, but the extending direction of the frame 450 is not limited to only the Y direction, and a frame 450 extending along the X direction may be further provided.

[0057] Frame fastening member 470 is a member for fixing frame 450 to case 400, and includes, for example, a fastening bolt. Frame 450 is formed with a hole portion (through hole) through which frame fastening member 470 for fixing frame 450 to case 400 can pass. Case 400 is formed with, for example, a screw portion (for example, a female screw) that screws into frame fastening member 470 (for example, a fastening bolt).

[0058] The cover 410 is a member that covers the upper side of the battery module group 115 (plurality of battery modules 110) arranged in the case 400, and is fastened to the case 400 by fastening members (not shown). This seals the battery module group 115, and the battery pack 500 is configured.

[0059] In the configuration of the battery module group 115, by consolidating the functions of the structural members into the side restraint members 200 and the end restraint members 300, it is possible to reduce the weight of the battery module group 115. Furthermore, by consolidating the functions of the structural members, it is possible to provide a battery pack 500 that can improve the mounting efficiency of the battery modules 110 in the case 400.

[0060] <Connection structure example 1> The end restraint members 300 of each battery module 110 are connected to the end restraint members 300 of other battery modules 110 disposed adjacently along the second direction (Y direction), forming long end restraint members 310.

[0061] FIG. 4 is a diagram showing a first example of a connecting structure for connecting end restraint members 300 (300a) according to an embodiment. In the first example of the connecting structure, a connecting structure using a connecting pin 610 will be described. In the example of FIG. 4, one end restraint member 300 (300a) will be described as being connected to another end restraint member 300 (300a). The end restraint member 300 (300a) is connected to the other end restraint member 300 (300a) by fitting the connecting pin 610 that abuts both the end restraint member 300 (300a) and the other end restraint member 300 (300a).

[0062] Recesses 611, 612 that fit with the connecting pin 610 are formed on the YZ plane of the one end restraint member 300 (300a). The connecting pin 610 fits into the recess 611 (first fitting portion) of the one end restraint member 300 (300a) and the recess 612 (second fitting portion) of the other end restraint member 300, thereby connecting the one end restraint member 300 (300a) and the other end restraint member 300 (300a).

[0063] In a state where the connecting pin 610 is fitted in the recess 611 (first fitting portion) and the recess 612 (second fitting portion), the fitting portions may be formed in different shapes so that the fitting state in the recess 611 (first fitting portion) differs from the fitting state in the recess 612 (second fitting portion). For example, as a different shape, the opening dimensions of the recesses may be changed so that the dimensional tolerances are different.

[0064] When the connecting pin 610 is engaged with the recess 611 (first engaging portion) and the recess 612 (second engaging portion), each engaging portion may be formed with a surface roughness such that the engaging state in the recess 611 (first engaging portion) differs from the engaging state in the recess 612 (second engaging portion).

[0065] For example, the recess 611 may be formed to provide a tight fitting state (first fitting state). Also, the recess 612 may be formed to provide a looser fitting state (second fitting state) than the first fitting state.

[0066] 4, at least different types of recesses 611, 612 are formed on the YZ surface of one end restraint member 300 (300a). That is, it is sufficient that the recess 611 for the first fitted state and the recess 612 for the second fitted state are formed on the YZ surface of one end restraint member 300 (300a).

[0067] The side restraint member 200 (200a) in one battery module 110 is coupled (contacts) with one end restraint member 300 (300a). Also, the side restraint member 200 (200b) in another adjacent battery module 110 is coupled (contacts) with the other end restraint member 300 (300a).

[0068] When the end restraint members 300 (300a) are connected to each other, adjacent side restraint members 200 (200a) and 200 (200b) are held in a sandwiched state between one end restraint member 300 (300a) and the other end restraint member 300 (300a). The end restraint member 300 (300a) has a hole (through hole) through which the fastening member 460 can pass, and the end restraint member 300 (300a) is connected by the fastening member 460 to the case 400 in which the battery module 110 is arranged.

[0069] The battery module 110, which is held in the XZ plane by the side restraint members 200 (200a, 200b), is held (connected) to the case 400 via the side restraint members 200 (200a, 200b) and the end restraint members 300 (300a, 300b).

[0070] It should be noted that with respect to the end restraint members 300 (300b) on the other end side of the battery module 110, the adjacent end restraint members 300 (300b) can also be similarly connected to each other by using the same connecting structure example 1.

[0071] In a connection structure using the connecting pin 610, one side is tightly fitted (first fitted state) and the other side is loosely fitted (second fitted state), thereby improving the ease of assembly when connecting the end restraint members 300. In other words, even before the end restraint members 300 are connected to each other, it becomes easy to align the side restraint members 200 in each battery module 110, and it becomes easier to adjust the positional relationship between the side restraint members 200 and the end restraint members 300.

[0072] <Connection structure example 2> Fig. 5 is a diagram showing a second example of a connecting structure for connecting end restraint members 300 (300a) according to the embodiment. In the second example of the connecting structure, a connecting structure using a stiffener 620 will be described. In the example of Fig. 5, as in the first example of the connecting structure, one end restraint member 300 (300a) will be connected to another end restraint member 300 (300a).

[0073] In connection structure example 2, similarly to connection structure example 1, the side restraint member 200 (200a) in one battery module 110 is connected (contacts) with one end restraint member 300 (300a). Also, the side restraint member 200 (200b) in another adjacent battery module 110 is connected (contacts) with the other end restraint member 300 (300a).

[0074] When the end restraint members 300 (300a) are connected to each other, adjacent side restraint members 200 (200a) and 200 (200b) are held in a sandwiched state between one end restraint member 300 (300a) and the other end restraint member 300 (300a).

[0075] As shown in Fig. 5, the stiffener 620 is a long reinforcing member extending in the Y direction, and the length of the stiffener 620 is arbitrary depending on the number of connected end restraint members 300. In the example shown in Fig. 5, the long stiffener 620 is provided on the top surface (XY plane) of one end restraint member 300 (300a) and the other end restraint member 300 (300a).

[0076] The long stiffener 620 and the end restraint member 300 (300a) and the other end restraint member 300 (300a) have holes (through holes) through which the fastening member 460 can pass. The long stiffener 620 and the end restraint member 300 and the other end restraint member 300 (300a) are fastened together in the vertical direction (Z direction) by the fastening member 460 and connected to the case 400, thereby connecting the one end restraint member 300 (300a) and the other end restraint member 300 (300a).

[0077] It should be noted that with respect to the end restraint members 300 (300b) at the other end side of the battery module 110, the adjacent end restraint members 300 (300b) can also be similarly connected to each other by using the same connecting structure example 2.

[0078] In connection structure example 2, the battery module 110, whose XZ plane is held by the side restraint members 200 (200a, 200b), is held (connected) to the case 400 via the side restraint members 200 (200a, 200b) and the end restraint members 300 (300a, 300b).

[0079] <Connection structure example 3> Fig. 6 is a diagram showing a third example of a connecting structure for connecting end restraint members 300 according to an embodiment. In the third example of a connecting structure, a connecting structure using a stiffener 630 will be described. In the example of Fig. 6, as in the first example of a connecting structure, one end restraint member 300 (300a) will be connected to another end restraint member 300 (300a).

[0080] In connection structure example 3, one side restraint member 200 (200a) in one battery module 110 is connected (contacts) with one end restraint member 300 (300a). Another side restraint member 200 (200b) in another adjacent battery module 110 is connected (contacts) with another end restraint member 300 (300a).

[0081] As shown in FIG. 6, one side restraint member 200 (200a) has a flange 232 (first flange) formed in the Y direction (Y+ direction) at the end of the side restraint member 200, and one end restraint member 300 (300a) has a step 332 (first step) that can be connected (abut) with the flange 232.

[0082] In addition, the other side restraint member 200 (200a) has a flange 231 (second flange) formed in the Y direction (Y-direction) at the end of the side restraint member 200, and the other end restraint member 300 (300a) has a step 331 (second step) that can be connected (abut) with the flange 231.

[0083] The steps 331 and 332 are formed with a screw portion 631 (for example, a male screw) that screws into a fastening member 632 (for example, a fastening nut).

[0084] As shown in FIG. 6, the stiffener 630 is a reinforcing member that reinforces the YZ surface of the end restraint member 300 (300a).

[0085] The stiffener 630, the flange 231, and the flange 232 have holes (through holes) through which the screw-threaded portions 631 formed in the steps 331, 332 can pass. The stiffener 630, the flange 231, and the flange 232 are fastened together to the steps 331, 332 by the fastening member 632, thereby connecting one end restraint member 300 (300a) and the other end restraint member 300 (300a).

[0086] Note that with respect to the end restraint members 300 (300b) on the other end side of the battery module 110, the adjacent end restraint members 300 (300b) can be similarly connected to each other by using the same connecting structure example 3.

[0087] In connection structure example 3, the battery module 110, whose XZ plane is held by the side restraint members 200 (200a, 200b), is held (connected) to the case 400 via the side restraint members 200 (200a, 200b) and the end restraint members 300 (300a, 300b).

[0088] <Battery cell> 7 is a diagram showing a cross-sectional structure (XZ cross section) of the battery cell 100. The battery cell 100 (secondary battery) may be an all-solid-state battery.

[0089] In the coordinate system in the figure, the X-axis indicates the longitudinal direction of the battery cell 100 (extension direction of the lead tab), and the Z-axis indicates the thickness direction of the battery cell 100 (thickness direction of the electrode body 2).

[0090] The battery cell 100 has an electrode body 2 (also referred to as a laminate in this embodiment) which is an energy storage element formed by stacking a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, an exterior member 18 which seals the periphery of the housed electrode body 2, lead tabs 13 and 14, and current collecting tabs 15 and 16.

[0091] The electrode body 2 has a two-layer structure of a positive electrode layer and a negative electrode layer. The positive electrode layer has two positive electrode layers 21 and 23, and the negative electrode layer has two negative electrode layers 22 and 24. A solid electrolyte layer 25 is provided between the positive electrode layer 21 and the negative electrode layer 22. A solid electrolyte layer 25 is also provided between the positive electrode layer 23 and the negative electrode layer 24. The positive electrode layer and the negative electrode layer may be single-phase (one-phase) or may be composed of multiple layers. When multiple positive electrode layers and multiple negative electrode layers are provided, as shown in FIG. 7, a solid electrolyte layer is provided between each positive electrode layer and negative electrode layer. In the example of FIG. 7, a structure of two positive electrode layers and negative electrode layers is illustrated, but the present invention is not limited to this example, and the positive electrode layers and negative electrode layers may be three or more layers.

[0092] The positive electrode layers 21 and 23 each have a positive electrode active material layer 711 and a positive electrode current collector 712. The positive electrode current collector 712 is common to the two positive electrode layers 21 and 23. The positive electrode current collector 712 is disposed at the center in the thickness direction (Z direction) of the electrode body 2, and the positive electrode active material layer 711 of the positive electrode layer 21 and the positive electrode active material layer 711 of the positive electrode layer 23 are laminated on the upper and lower sides of the positive electrode current collector 712.

[0093] The negative electrode layer 22 is disposed (stacked) on the upper surface side of the electrode body 2 in the thickness direction (Z direction) with respect to the positive electrode layer 21, and the negative electrode layer 24 is disposed (stacked) on the lower surface side of the electrode body 2 in the thickness direction (Z direction) with respect to the positive electrode layer 23. The negative electrode layers 22 and 24 are stacked so as to sandwich the positive electrode layers 21 and 23. The negative electrode layers 22 and 24 each have a negative electrode active material layer 721 and a negative electrode current collector 722. The two negative electrode current collectors 722 are each formed in a layered form on the outermost layer of the electrode body 2. The configuration of the positive electrode layer and the negative electrode layer is not limited to the stacking order shown in FIG. 7, and may be stacked so that two positive electrode layers sandwich two negative electrode layers.

[0094] The active material constituting the positive electrode active material layer 711 may be an NCM-based (ternary active material) material in which cobalt, nickel, and manganese are mixed, such as lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide.

[0095] Examples of the active material constituting the negative electrode active material layer 721 include lithium-based materials and silicon-based materials. Other examples of the material constituting the negative electrode active material layer 721 include carbon materials such as graphite, soft carbon, and hard carbon, tin-based materials, and transition metal oxides (for example, lithium titanate: LTO).

[0096] The solid electrolyte layer 25 is made of, for example, a solid electrolyte having ion conductivity, and examples of the material include a sulfide-based solid electrolyte material, an oxide-based solid electrolyte material, a nitride-based solid electrolyte material, and a halide-based solid electrolyte material.

[0097] The positive electrode current collector 712 and the negative electrode current collector 722 are made of, for example, a metal foil, a metal sheet, or a metal plate of aluminum, copper, SUS, or the like. The positive electrode active material layer 711, the negative electrode active material layer 721, and the solid electrolyte layer 25 may be formed by binding particles of the materials constituting them with an organic polymer compound binder. The positive electrode active material layer 711 or the negative electrode active material layer 721 may contain an electronic conductive assistant such as carbon (particles, fibers), metal powder, or the like. A solid electrolyte powder may also be disposed in the positive electrode active material layer 711 or the negative electrode active material layer 721 to construct an ion conductive path.

[0098] The exterior member 18 is a container that houses the electrode body 2. The exterior member 18 is formed by folding one sheet-like material in two, or by bonding a plurality of sheets of sheet-like material together. The material of the exterior member 18 is formed, for example, by covering the front and back surfaces of a metal layer with an insulating layer.

[0099] One end of the lead tab 13 is located outside the exterior member 18, and the other end is located inside the exterior member 18. The other end of the lead tab 13 is connected to the positive electrode current collector 712 inside the exterior member 18 via a current collecting tab 15, and the lead tab 13 forms a tab for the positive electrode. The lead tab 13 and the current collecting tab 15 are formed, for example, from a conductive metal sheet or metal plate.

[0100] One end of the lead tab 14 is located outside the exterior member 18, and the other end is located inside the exterior member 18. The other end of the lead tab 14 is connected to the negative electrode current collector 722 inside the exterior member 18 via a current collecting tab 16, and the lead tab 14 forms a tab for the negative electrode. The lead tab 14 and the current collecting tab 16 are formed, for example, from a conductive metal sheet or metal plate. The electrode body 2 can be charged or discharged by connecting the lead tabs 13 and 14 to a charger or an electric load.

[0101] [Embodiment 2] In the second embodiment, a structure for preventing thermal chain reaction (hereinafter, thermal chain reaction prevention structure) in the battery pack 500 described in the previous embodiment will be described. Fig. 8 is a diagram for explaining the thermal chain reaction prevention structure of the battery pack 500 according to the second embodiment. Fig. 8 shows a YZ cross section of the battery pack 500. Focusing on one battery module 110 among the battery module group 115, the battery module 110 arranged adjacent to this battery module 110 in the Y direction is shown.

[0102] 8 shows a state in which the battery module 110 (laminated body 111) is placed in the case 400 and covered from above with a cover 410, but this also shows the arrangement of the battery cells 100 in the YZ cross section. The first surface 101 (101a, 101b) is a surface that is perpendicular to the lower surface 103 of the battery module 110 (laminated body 111) and is a surface that is aligned along the lamination direction (perpendicular to the paper surface).

[0103] The side restraint members 200 (200a, 200b) face the first surfaces 101 (101a, 101b) of the battery modules 110 and extend in the stacking direction. The first surfaces 101 (101a, 101b) and the side restraint members 200 (200a, 200b) are joined by joining members 701 (FIG. 7).

[0104] A first distance (e.g., 810 in FIG. 8) between the upper end of the side restraint member 200 (200a, 200b) and the cover 410 is shorter than a second distance 820 between the upper surface of the battery module 110 (stacked body 111, battery cells 100) and the cover 410. The side restraint members 200 (200a, 200b) and the battery module 110 (stacked body 111, battery cells 100) are formed so as to satisfy this positional relationship (first distance 810<second distance 820).

[0105] 8, for example, the first distance 810 may be the distance when the upper ends of the side restraint members 200 (200a, 200b) are in contact with the cover 410. Also, as long as the above positional relationship is satisfied, the first distance 810 may be the distance when the upper ends of the side restraint members 200 (200a, 200b) are separated from the cover 410 by a predetermined gap in the Z direction (vertical direction).

[0106] In the case 400, a plurality of battery modules 110 are arranged in a direction (Y direction: intersecting direction) intersecting the XZ plane (first surface 101) of the laminated body 111. For example, as shown in Fig. 8, a side restraint member (e.g., 200 (200a)) is arranged to face another side restraint member (e.g., 200 (200b)) of another battery module 110 arranged adjacently in the case 400 in the intersecting direction.

[0107] The positional relationship between the first distance 810 and the second distance 820 (first distance 810<second distance 820) is also similar for the other side restraint members (200 (200b)) in the other adjacent battery modules 110.

[0108] According to the thermal chain reaction prevention structure of the second embodiment, even when a battery cell 100 constituting the battery module 110 experiences thermal runaway, the flow of gas and ejected material ejected from the battery cell 100 is suppressed by the side restraint member 200. This makes it possible to prevent the ejected gas and ejected material from flowing into the side of another battery cell 100 that is adjacently arranged in the cross direction relative to the side restraint member 200. The side restraint member 200 functions as a fire wall surface, and can suppress and prevent thermal chain reaction of the battery cells 100.

[0109] [Embodiment 3] In the third embodiment, another thermal chain reaction prevention structure in the battery pack 500 described in the previous embodiment will be described. FIG. 9 is a diagram for explaining the thermal chain reaction prevention structure of the battery pack 500 according to the third embodiment. FIG. 9 shows a YZ cross section of the battery pack 500. As in FIG. 8, attention is focused on one battery module 110 among the battery module group 115, and the battery module 110 arranged adjacent to this battery module 110 in the Y direction is shown. FIG. 9 shows a state in which the battery module 110 (laminated body 111) is arranged in the case 400 and covered from above with a cover 410, but it is also the arrangement state of the battery cells 100 in the YZ cross section.

[0110] As in the second embodiment, the first surface 101 (101a, 101b) is a surface that is perpendicular to the lower surface 103 of the battery module 110 (stacked body 111) and is a surface along the stacking direction (direction perpendicular to the paper surface). The side restraint members 200 (200a, 200b) face the first surface 101 (101a, 101b) of the battery module 110 and extend in the stacking direction. The first surface 101 (101a, 101b) and the side restraint members 200 (200a, 200b) are joined by a joining member 701 (FIG. 7).

[0111] In other thermal chain reaction prevention structures in embodiment 3, similarly to embodiment 2, the side restraint members 200 (200a, 200b) and the battery module 110 (stacked body 111, battery cells 100) may be formed so as to satisfy the positional relationship between the first distance 810 and the second distance 820 (first distance 810<second distance 820). That is, the first distance 810 between the upper end of the side restraint members 200 (200a, 200b) and the cover 410 may be shorter than the second distance 820 between the upper surface of the battery module 110 (stacked body 111) and the cover 410.

[0112] 9, first distance 810 shows a state in which the upper end of side restraint member 200 (200a, 200b) and cover 410 are separated by a predetermined gap, but cover 410 may be formed so that the predetermined gap is labyrinth-shaped. Also, first distance 810 may be the distance in a state in which the upper end of side restraint member 200 (200a, 200b) and cover 410 are in contact with each other, as shown in FIG.

[0113] In the case 400, a plurality of battery modules 110 are arranged in a direction (Y direction: intersecting direction) intersecting the XZ plane (first surface 101) of the laminated body 111. For example, as shown in Fig. 9, a side restraint member (e.g., 200 (200a)) is arranged facing another side restraint member (e.g., 200 (200b)) of another battery module 110 arranged adjacently in the case 400 in the intersecting direction. The positional relationship between the first distance 810 and the second distance 820 is also the same for the other side restraint member (200 (200b)) of the other adjacent battery module 110.

[0114] 9, the cover 410 is formed with a plurality of protrusions 415 extending downward toward the battery module 110 (the laminate 111, the battery cells 100) at positions spaced apart along the Y direction. For example, when the cover 410 is made of a flame-retardant resin, the plurality of protrusions 415 can be molded integrally with the cover 410. Also, when the cover 410 is formed by press molding of a metal plate, the plurality of protrusions 415 may be formed separately and attached to the cover 410 by welding or the like.

[0115] 9, and the other side restraint member 200 (200b) of the other battery cell 100 arranged adjacently in the intersecting direction are positioned between the multiple protrusions 415. Similarly, the side restraint member 200 (200b) of the other battery cell 100 arranged adjacently in the intersecting direction are positioned between the multiple protrusions 415.

[0116] The lower ends 416 of the multiple protrusions 415 are extended so as to be closer to the battery module 110 (stacked body 111, battery cells 100) than the upper ends 910 of the side restraint members 200 (200a, 200b) and the upper ends 920 of the other side restraint members 200 (200b, 200a). The side restraint members 200 (200a, 200b), the multiple protrusions 415, and the battery module 110 (stacked body 111, battery cells 100) are formed to satisfy this positional relationship.

[0117] The positional relationship in the Y direction (intersecting direction) between side restraint members 200 (200a, 200b) located between the multiple protruding portions 415 and the multiple protruding portions 415 may be in a state in which they are separated by a specified gap, as shown in Fig. 9. With side restraint member 200 and other side restraint members 200 located between the multiple protruding portions 415, side restraint member 200 and other side restraint members 200 are disposed at positions separated from the multiple protruding portions 415 in the Y direction (intersecting direction). The multiple protruding portions 415 may be formed so that the specified gap in the Y direction (intersecting direction) is labyrinth-shaped.

[0118] 9, the positional relationship in the Y direction (intersecting direction) between the side restraint member 200 and the multiple protruding portions 415 may be in an abutting state. In a state in which the side restraint member 200 and the other side restraint members 200 are positioned between the multiple protruding portions 415, the side restraint member 200 and the other side restraint members 200 may be disposed in a position in which they abut against the multiple protruding portions 415 in the Y direction (intersecting direction).

[0119] According to the thermal chain reaction prevention structure of the third embodiment, even when a battery cell 100 constituting the battery module 110 experiences thermal runaway, the flow of gas and ejected material ejected from the battery cell 100 is suppressed by the side restraint member 200. This makes it possible to prevent the ejected gas and ejected material from flowing into the side of another battery cell 100 that is adjacently arranged in the cross direction relative to the side restraint member 200. The side restraint member 200 functions as a fire wall surface, and can suppress and prevent thermal chain reaction of the battery cells 100.

[0120] <Summary of the embodiment> The above embodiment discloses at least the following battery pack.

[0121] (Item 1) The battery pack of the above embodiment is a battery pack (500) having a case (400), a battery module (110) disposed in the case, and a cover (410) covering an upper portion of the battery module, The battery module (110) includes: A stack (111) in which a plurality of secondary batteries are stacked; a side restraining member (200) facing the first surface (101) of the stack and extending in the stacking direction of the stack, The first surface (101) is a surface that is perpendicular to the lower surface (103) of the stack and is aligned along the stacking direction, A first distance (810) between the top of the side restraint member and the cover is less than a second distance (820) between the top surface of the stack and the cover.

[0122] According to the battery pack of item 1, in a battery module that can improve mounting efficiency while suppressing an increase in the weight of the battery module, a battery pack can be provided that can suppress thermal chain reaction when a battery cell experiences thermal runaway.

[0123] (Item 2) The first distance (810) is the distance when the upper end of the side restraint member and the cover are in contact with each other, or the distance when the upper end and the cover are spaced apart in the vertical direction.

[0124] According to the battery pack of item 2, even when a battery cell 100 constituting the battery module 110 experiences thermal runaway, the flow of gas and ejected material ejected from the battery cell 100 is suppressed by the side restraint member 200. This makes it possible to prevent the ejected gas and ejected material from flowing into the side of another battery cell 100 that is adjacently arranged in the cross direction relative to the side restraint member 200. The side restraint member 200 functions as a fire wall surface, and can suppress and prevent thermal chain reaction of the battery cells 100.

[0125] (Item 3) The first surface (101) and the side restraint member (200) are joined by a joining member.

[0126] According to the battery pack of item 3, the functions performed by the cross member of the housing (case) and the functions performed by the bind bar in the conventional technology can be consolidated into the side restraint member 200 (200a, 200b) in the battery module 110 and battery module group 115 of this embodiment.

[0127] (Item 4) The battery module (110) A plurality of the laminated bodies are arranged in a cross direction (Y direction) that crosses the first surface (XZ surface), The side restraint member (200) is The battery module is disposed so as to face, in the intersecting direction, another side restraint member of another battery module disposed adjacently within the case.

[0128] According to the battery pack of item 4, the functions performed by the cross members of the housing (case) and the functions performed by the bind bars in the conventional technology can be consolidated into the side restraint members 200 (200a, 200b) in the battery module 110 and the battery module group 115 of the present embodiment. By consolidating the functions of the structural members, it is possible to provide a battery pack 500 that can improve the mounting efficiency of the battery module 110 in the case 400.

[0129] (Item 5) The cover (410) has a plurality of protrusions (415) extending downward toward the battery module at positions spaced apart along the intersecting direction, The side restraint member (200) and the other side restraint member (200) are positioned between the plurality of protrusions (415).

[0130] (Item 6) The lower ends (416) of the multiple protrusions are extended so as to be positioned closer to the battery module (110) than the upper ends (910a, 910b) of the side restraint member and the other side restraint member.

[0131] (Item 7) When positioned between the multiple protrusions (415), the side restraint member (200) and the other side restraint member (200) are arranged at a position spaced apart from the multiple protrusions (415) in the intersecting direction.

[0132] (Item 8) When positioned between the multiple protrusions (415), the side restraint member (200) and the other side restraint member (200) are arranged in a position abutting the multiple protrusions (415) in the intersecting direction.

[0133] According to the battery pack of items 5 to 8, even when a battery cell 100 constituting the battery module 110 experiences thermal runaway, the flow of gas and ejected material ejected from the battery cell 100 is suppressed by the side restraint member 200. This makes it possible to prevent the ejected gas and ejected material from flowing into the side of another battery cell 100 that is adjacently arranged in the cross direction relative to the side restraint member 200. The side restraint member 200 functions as a fire wall surface, and can suppress and prevent thermal chain reaction of the battery cells 100.

[0134] The present invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0135] 100: battery cell (secondary battery), 110: laminate, 200: side restraint member, 231: flange, 232: flange, 300: end restraint member, 310: long end restraint member, 331: step, 332: step, 400: case (battery case), 410: cover, 415: protrusion, 450: frame, 455: reinforcing part, 500: battery pack

Claims

1. A battery pack including a case, a battery module disposed in the case, and a cover covering an upper portion of the battery module, The battery module includes: A stack of a plurality of secondary batteries; a side restraining member facing the first surface of the stack and extending in the stacking direction of the stack, The first surface is a surface that is perpendicular to a lower surface of the stack and aligned along the stacking direction, A battery pack, comprising: a first distance between an upper end of the side restraint member and the cover, the first distance being shorter than a second distance between an upper surface of the stack and the cover.

2. 2. The battery pack according to claim 1, wherein the first distance is a distance when the upper end of the side restraint member is in contact with the cover, or a distance when the upper end is spaced apart from the cover in the vertical direction.

3. The battery pack according to claim 1 , wherein the first surface and the side restraint member are joined by a joining member.

4. The battery module includes: A plurality of the laminates are arranged in a cross direction crossing the first surface of the laminate, The side restraint member is 2 . The battery pack according to claim 1 , wherein the battery pack is disposed in a state facing, in the intersecting direction, another side restraint member of another battery module disposed adjacent to the battery pack in the case.

5. the cover has a plurality of protrusions extending downward toward the battery module at positions spaced apart along the intersecting direction, The battery pack according to claim 4 , wherein the side restraint member and the other side restraint member are positioned between the plurality of protrusions.

6. The battery pack according to claim 5, wherein the lower ends of the plurality of protrusions are extended so as to be positioned closer to the battery module than the upper ends of the side restraint member and the other side restraint member.

7. The battery pack according to claim 5 or 6, characterized in that when positioned between the plurality of protrusions, the side restraint member and the other side restraint member are arranged at a position spaced apart from the plurality of protrusions in the intersecting direction.

8. The battery pack according to claim 5 or 6, characterized in that when positioned between the plurality of protrusions, the side restraint member and the other side restraint member are arranged in a position abutting the plurality of protrusions in the intersecting direction.

Images