Power storage module

Abstract

Provided is a power storage module (10) comprising: a plurality of power storage devices (20); a holder (40) that holds the plurality of power storage devices (20); and a housing (50) that accommodates the holder (40). The housing (40) includes a lower housing (51) and an upper housing (52). The lower housing (51) and the upper housing (52) are sealed by a sealing structure (60). The sealing structure (60) has: a groove part (61) provided to a first contact surface (51C) which is part of the lower housing (51) and which contacts the upper housing (52) and / or a second contact surface (52C) which is part of the upper housing (52) and which contacts the lower housing (51); and a liquid gasket (65) provided in the groove part (61). The groove part (61) includes: a straight section (61L) having a curvature less than a first curvature; and a first bent section (61M) having a curvature equal to or greater than the first curvature. The groove depth of the first bent section (61M) is greater than the groove depth of the straight section (61L).

Description

Power storage module

[0001] The present disclosure relates to a power storage module.

[0002] A power storage module including a plurality of power storage devices, a holder for holding the plurality of power storage devices, and a housing for housing the holder is known (for example, Patent Document 1). The power storage module may be used outdoors. For the housing of a power storage module for outdoor use, a sealing structure for waterproofing and dustproofing is required. In the sealing structure of the housing, a liquid gasket may be used.

[0003] Japanese Unexamined Patent Application Publication No. 2017-152165

[0004] Here, there is a demand for a power storage module that can be used under a wider range of conditions and has better performance.

[0005] Therefore, an object of the present disclosure is to provide a power storage module that can improve reliability.

[0006] The power storage module according to the present disclosure is a power storage module including a plurality of power storage devices, a holder for holding the plurality of power storage devices, and a housing for housing the holder, wherein the housing includes a first housing and a second housing, the first housing and the second housing are sealed by a sealing structure, the sealing structure has a groove portion provided on a first contact surface of the first housing with the second housing or / and a second contact surface of the second housing with the first housing, and a liquid gasket provided in the groove portion, the groove portion includes a straight portion having a curvature less than a first curvature and a bent portion having a curvature greater than or equal to the first curvature, and the groove depth of the bent portion is deeper than the groove depth of the straight portion.

[0007] According to the power storage module of the present disclosure, the reliability can be improved.

[0008] It is a schematic cross-sectional view showing a power storage module which is an example of an embodiment. It is a cross-sectional view showing a power storage device according to the embodiment. It is a plan view showing a lower housing according to the embodiment. It is a detailed view of part A in FIG. 3. It is a schematic view showing a coating process of a liquid gasket. It is a plan view showing a groove portion which is an example of an embodiment.

[0009] An example of an embodiment of this disclosure is described in detail below. In the following description, specific shapes, materials, directions, numerical values, etc., are examples provided to facilitate understanding of this disclosure and can be modified as appropriate to suit the application, purpose, specifications, etc.

[0010] It should be noted that this disclosure is not limited to the embodiments and their modifications described above, and various changes and improvements are possible within the scope of the claims of this application.

[0011] [Energy Storage Module] An example of an embodiment, the energy storage module 10, will be described using Figure 1.

[0012] The energy storage module 10 is mounted on an electric vehicle as a power source for the motor that drives the electric vehicle. However, the energy storage module of this disclosure is not limited to being mounted on an electric vehicle, and may be used as a power source for electric equipment driven by motors, such as power tools, electric assist bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. Furthermore, the applications of the energy storage module of this disclosure are not limited, and may be used as a power source for various electrical equipment used indoors and outdoors, such as cleaners, wireless devices, lighting devices, digital cameras, and video cameras.

[0013] As will be described in detail later, the energy storage module 10 makes it possible to improve energy density while maintaining the sealing performance of the sealing structure 60 of the housing 50. In the following, the axial direction of the energy storage device 20 housed in the energy storage module 10 may be considered as the vertical direction, and each component may be described using the upper or lower side.

[0014] Each energy storage module 10 comprises a plurality of energy storage devices 20, a holder 40 for holding the plurality of energy storage devices 20, and a housing 50 for housing the holder 40, the details of which will be described later.

[0015] Multiple energy storage devices 20 may be packed as densely as possible within the energy storage module 10, with safety in mind, and adjacent energy storage devices 20 may be arranged in close proximity to each other. For example, in a plan view, six energy storage devices 20 may surround one energy storage device 20 (or be arranged in a staggered pattern). Alternatively, multiple energy storage devices 20 may be arranged such that the closest energy storage devices 20 are placed on each of the four sides. Details of the energy storage devices 20 will be described later.

[0016] The holder 40 holds the energy storage device 20. The holder 40 is divided vertically into a lower holder 41 and an upper holder 42. If the holder 40 has electrical insulation properties, it is made of, for example, a thermoplastic resin. Thermoplastic resins are broadly classified into general-purpose plastics and engineering plastics, and polycarbonate, polybutylene terephthalate, etc. are used. The lower holder 41 and the upper holder 42 are fixed to each other via a fixing member or using locking parts provided on each holder.

[0017] The lower holder 41 has a plurality of housing sections 43, which are cylindrical recesses that accommodate the lower portion of each energy storage device 20. Positive electrode current collector plates and negative electrode current collector plates for collecting current from the energy storage device 20 may be provided on the lower surface of the lower holder 41. Each of the plurality of housing sections 43 has a through hole that forms an opening on the lower surface of the lower holder 41, and a plurality of leads of the positive electrode current collector plate and negative electrode current collector plate may be inserted through this opening and connected to the sealing body 26 or the outer casing 25.

[0018] The upper holder 42 has a plurality of accommodating sections 44, which are cylindrical recesses that house the upper portion of each energy storage device 20. Positive electrode current collector plates and negative electrode current collector plates for collecting current from the energy storage device 20 may be provided on the upper surface of the upper holder 42. Each of the plurality of accommodating sections 44 has a through hole that forms an opening on the upper surface of the upper holder 42, and a plurality of leads of the positive electrode current collector plate and negative electrode current collector plate are inserted through this opening, and these leads may be connected to the sealing body 26 or the outer casing 25.

[0019] The housing 50 houses the holder 40. The housing 50 is divided vertically into a lower housing 51 (first housing) and an upper housing 52 (second housing). In this disclosure, the housing may also be divided horizontally or vertically. The housing 50 is made of a metal such as aluminum. However, the housing 50 is not limited to metal and may be made of resin.

[0020] The lower housing 51 has a plate-shaped first base portion 51A, an annular first wall portion 51B extending vertically from the first base portion 51A, and a housing portion 53 in which the lower part of the holder 40 is housed. The upper housing 52 has a plate-shaped second base portion 52A, an annular second wall portion 52B extending vertically from the second base portion 52A, and a housing portion 54 in which the upper part of the holder 40 is housed. In the housing 50, the lower housing 51 and the upper housing 52 are fixed together by a fixing structure (not shown). The fixing structure may be, for example, a fixing structure using fastening members such as screws and bolts, or a structure in which an engaging portion and a claw portion are engaged. In addition, in the housing 50, the lower housing 51 and the upper housing 52 are sealed together by a sealing structure 60, which will be described in detail later.

[0021] [Energy Storage Device] The energy storage device 20 according to the embodiment will be described with reference to Figure 2.

[0022] In this embodiment, the energy storage device 20 is a cylindrical lithium-ion secondary battery, but it may also be a nickel-metal hydride battery, a capacitor, or the like. The energy storage device 20 includes, for example, an electrode group 24 in which a strip-shaped positive electrode 21 and a strip-shaped negative electrode 22 are wound with a strip-shaped separator 23 in between, a cylindrical outer container 25 that houses the electrode group 24 together with an electrolyte, a sealing body 26 that seals the opening of the outer container 25 in an insulated state, a foil-shaped positive electrode lead 27 that electrically connects the positive electrode 21 and the sealing body 26, and a negative electrode lead 28 that electrically connects the negative electrode 22 and the outer container 25. An insulating gasket 29 may be placed between the outer circumference of the sealing body 26 and the inner surface of the opening of the outer container 25.

[0023] An annular groove 25A is formed on the outer circumferential surface of the outer can 25 on the opening side. This groove 25A is formed as an annular projection on the inner circumferential surface of the outer can 25. The gasket 29 and the sealing body 26 are placed on this annular projection inside the outer can 25. Furthermore, the opening end of the outer can 25 is crimped so that it bends inward with the gasket 29 positioned on the inner circumferential side. The opening of the outer can 25 is sealed by the sealing body 26 being sandwiched axially between the crimped opening end and the projection via the gasket 29.

[0024] The sealing body 26 may be provided with a current interruption mechanism (CID) or an exhaust valve that ruptures when the pressure inside the outer casing 25 exceeds a predetermined level. An insulating plate 30 may also be provided between the electrode group 24 and the bottom of the outer casing 25, or between the electrode group 24 and the protrusion (groove 25A) to insulate the electrode group 24 from the outer casing 25. If an insulating plate 30 is provided, the positive electrode lead 27 may extend through a through hole formed in the insulating plate 30. The negative electrode lead 28 may extend either through a through hole formed in the insulating plate 30 or by bypassing the insulating plate 30. In the energy storage device 20, as described above, the positive electrode terminal may be located on the top surface of the sealing body 26, and the negative electrode terminal may be located on the crimped shoulder portion of the outer casing 25.

[0025] The configuration of the energy storage device of this disclosure is not limited to the above configuration. In the energy storage device of this disclosure, an outer casing and a sealing plate that crimps and closes the opening of the outer casing are electrically connected, and a terminal member connected to the positive electrode as a first terminal is placed in an insertion hole formed in the bottom of the outer casing, insulated from the outer casing. In this case, the sealing plate connected to the negative electrode and the outer casing function as a second terminal.

[0026] [Sealing Structure] An example of a sealing structure 60, which is an embodiment, will be described using Figures 3 to 6.

[0027] As described above, the sealing structure 60 seals the lower housing 51 and the upper housing 52, thereby sealing the housing 50. The sealing structure 60, as will be described in detail later, improves the sealing performance of the housing 50.

[0028] More specifically, the sealing structure 60 allows for sufficient sealing performance to be maintained even when the widthwise size of the sealing structure 60 is reduced. In other words, even when the volume of the first base 51A, first wall 51B, second base 52A, and second wall 52B surrounding the housing space of the housing 50 (lower housing 51 and upper housing 52) is reduced, the sealing performance of the sealing structure 60 of the housing 50 can be maintained.

[0029] This makes it possible to improve the energy density of the energy storage module 10 while maintaining the sealing performance of the sealing structure 60 of the housing 50. As a result, the performance of the energy storage module 10 can be improved.

[0030] As shown in Figures 3 and 4, the sealing structure 60 has a groove 61 provided on the first contact surface 51C of the lower housing 51 with the upper housing 52, and a liquid gasket 65 (see Figure 5) provided in the groove 61. Alternatively, a projection may be provided on the second contact surface 52C of the upper housing 52 with the lower housing 51, and this projection may be housed in the groove 61.

[0031] In this embodiment, a groove 61 is provided on the first contact surface 51C, but the invention is not limited to this. In the present invention, a groove may be provided on the second contact surface 52C, or grooves communicating with each other may be provided on the first contact surface 51C and the second contact surface 52C.

[0032] The groove 61 is formed to be recessed downward on the first contact surface 51C of the lower housing 51 and the upper housing 52. The groove 61 may be formed approximately in the center in the width direction of the first contact surface 51C. The groove 61 is formed along the edge of the housing portion 53 of the lower housing 51. The groove 61 is formed in a rectangular shape in a cross-sectional view along the vertical direction.

[0033] The groove 61 helps to suppress the movement of the liquid gasket 65. Furthermore, the groove 61 increases the contact area between the lower housing 51 and the liquid gasket 65. This improves the sealing performance of the sealing structure 60.

[0034] Here, as shown in Figure 4, the groove 61 includes a straight section 61L, a first curved section 61M, and a second curved section 61N, so as to bypass the through hole H provided at the corner of the first contact surface 51C. The through hole H is a hole through which fastening members such as screws and bolts pass for fixing the lower housing 51 and the upper housing 52. The straight section 61L is the part of the groove 61 having a curvature less than the first curvature in a plan view. The first curved section 61M is the part of the groove 61 having a curvature greater than or equal to the first curvature and less than the second curvature in a plan view. The second curved section 61N is the part of the groove 61 having a curvature greater than or equal to the second curvature in a plan view. The second curvature is a curvature greater than the first curvature.

[0035] In this embodiment, the groove 61 is configured to include a straight section 61L, a first curved section 61M, and a second curved section 61N so as to bypass the through hole H provided in the first contact surface 51C, but the invention is not limited to this configuration. In this disclosure, the first curved section 61M or the second curved section 61N may be included so as to follow the corner of the first contact surface 51C.

[0036] The liquid gasket 65, for example, is fluid at room temperature, and after being applied to the joint surface, it dries or becomes uniform after a certain period of time, forming an elastic or adhesive thin layer. The material of the liquid gasket 65 is preferably an epoxy adhesive with methanol resistance, an epoxy-modified silicone adhesive, a silicone adhesive, a fluorine-based adhesive, or an elastic adhesive such as butyl rubber-based urethane RTV rubber or silicone RTV rubber.

[0037] Here, as shown in Figure 5, in the step of applying liquid gasket 65 to the groove 61, the nozzle N that discharges the liquid gasket 65 is moved along the groove 61. At this time, for example, a robot moves the nozzle N. The robot moves the nozzle N at a constant speed in the straight section 61L, but often decelerates the nozzle N in the curved section (first curved section 61M or second curved section 61N). In other words, the speed at which the nozzle N passes through the curved section is slower than the speed at which the nozzle N passes through the straight section 61L.

[0038] Therefore, the amount of liquid gasket 65 applied in the curved section is greater than the amount applied in the straight section 61L. Normally, the amount of liquid gasket 65 applied by nozzle N is determined based on the amount applied when passing through the straight section 61L. Therefore, the amount of liquid gasket 65 applied in the curved section may be greater than the standard amount.

[0039] If the amount of liquid gasket 65 applied exceeds the standard amount, it may overflow from the groove 61 onto the first contact surface 51C, creating a gap between the lower housing 51 and the upper housing 52. In this case, the sealing performance of the sealing structure 60 of the housing 50 will be reduced. Furthermore, if the liquid gasket 65 overflows from the first contact surface 51C and spills onto the side surface of the housing 50, the appearance of the energy storage module 10 will be impaired. Moreover, if the liquid gasket 65 overflows around the through hole H, there is a risk that the liquid gasket 65 may get caught in fastening members such as screws and bolts and peel off when fastening them.

[0040] Therefore, as shown in Figure 6, in the groove section 61, the groove depth of the first curved section 61M is formed to be deeper than the groove depth of the straight section 61L. Also, in the groove section 61, the groove depth of the second curved section 61N is formed to be deeper than the groove depth of the first curved section 61M. In other words, in the groove section 61, the groove depth increases as the curvature increases. Note that the bottom surface of the boundary between the straight section 61L and the first curved section 61M, or the boundary between the second curved section 61N and the first curved section 61M, may be formed as an inclined section rather than a stepped section.

[0041] According to the above configuration, even if the amount of liquid gasket 65 applied in the curved portion exceeds the standard amount, it is possible to prevent the liquid gasket 65 from overflowing from the groove portion 61. This prevents a decrease in the sealing performance of the sealing structure 60 of the housing 50. Furthermore, the appearance of the energy storage module 10 is not impaired.

[0042] In the groove portion of the present disclosure, in the straight portion, a first region and a second region are provided which are arranged in the circumferential direction in which the groove portion extending perpendicular to the first direction. Among the circumferential directions, the first region is closer to the bent portion than the second region, and the groove depth of the first region may be deeper than the groove depth of the second region. With this configuration, it is possible to reduce the bent portion in the groove portion and suppress the liquid gasket from overflowing from the groove portion even when decelerating before the nozzle reaches the bent portion.

[0043] [Summary] The present invention will be further described by the following embodiments. Configuration 1: A power storage module including a plurality of power storage devices, a holder that holds the plurality of power storage devices, and a housing that houses the holder, The housing includes a first housing and a second housing, The first housing and the second housing are sealed by a sealing structure, The sealing structure has a groove portion provided on a first contact surface of the first housing with the second housing or / and a second contact surface of the second housing with the first housing, and a liquid gasket provided in the groove portion, The groove portion includes a straight portion having a curvature less than a first curvature and a bent portion having a curvature greater than or equal to the first curvature, The groove depth of the bent portion is deeper than the groove depth of the straight portion, A power storage module. Configuration 2: The power storage module according to Configuration 1, The bent portion includes a first bent portion having a curvature less than a second curvature greater than the first curvature and a second bent portion having a curvature greater than or equal to the second curvature, The groove depth of the second bent portion is deeper than the groove depth of the first bent portion, A power storage module. Configuration 3: The power storage module according to Claim 3, In the straight portion, a first region and a second region are provided which are arranged in the direction in which the straight portion extends, In the direction in which the groove portion extends, the first region is closer to the bent portion than the second region, The groove depth of the first region is deeper than the groove depth of the second region, A power storage module.

[0044] Note that the present disclosure is not limited to the above-described embodiments and their modified examples, and various changes and improvements can of course be made within the scope of the matters described in the claims of the present application.

[0045] 10 Energy storage module, 20 Energy storage device, 21 Positive electrode, 22 Negative electrode, 23 Separator, 24 Electrode group, 25 Outer casing, 25A Groove section, 26 Sealing body, 27 Positive electrode lead, 28 Negative electrode lead, 29 Gasket, 30 Insulating plate, 40 Holder, 41 Lower holder, 42 Upper holder, 43 Housing section, 44 Housing section, 50 Housing, 51 Lower housing, 51A Base section, 51B Wall section, 51C First contact surface, 51D First region, 52 Upper housing, 52A Base section, 52B Wall section, 52C Second contact surface, 52D Second region, 60 Sealing structure, 61 Groove section, 61L Straight section, 61M First curved section, 61N Second curved section, 65 Liquid gasket

Claims

1. An energy storage module comprising: a plurality of energy storage devices; a holder for holding the plurality of energy storage devices; and a housing for housing the holder, wherein the housing includes a first housing and a second housing, the first housing and the second housing are sealed by a sealing structure, the sealing structure having grooves provided on a first contact surface of the first housing with the second housing, and / or a second contact surface of the second housing with the first housing, and a liquid gasket provided in the grooves, the grooves including a straight portion having a curvature less than a first curvature and a curved portion having a curvature greater than or equal to the first curvature, and the groove depth of the curved portion being deeper than the groove depth of the straight portion.

2. An energy storage module according to claim 1, wherein the curved portion includes a first curved portion having a curvature less than a second curvature greater than the first curvature, and a second curved portion having a curvature greater than or equal to the second curvature, and the groove depth of the second curved portion is deeper than the groove depth of the first curved portion.

3. An energy storage module according to claim 1, wherein the straight portion has a first region and a second region aligned in the direction in which the straight portion extends, the first region is closer to the curved portion than the second region in the direction in which the groove extends, and the groove depth of the first region is deeper than the groove depth of the second region.

Images