Power storage module

Abstract

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), wherein: the housing (50) includes an upper housing (51) and a lower housing (52) that are side by side in the vertical direction; the upper housing (51) and the lower housing (52) are sealed by a sealing structure (60); the sealing structure (60) has a first groove (62) provided on a first contact surface of the upper housing (51) with the lower housing (52), a ridge-like protrusion (61) provided to a second contact surface of the lower housing (52) with the upper housing (51) and accommodated in the first groove (61), and a liquid gasket (65) provided between the first groove (62) and the protrusion (61); and a second groove (63) is formed in the top surface of the protrusion (61) so as to face the first groove (62), and the liquid gasket (55) is accommodated in the second groove (63).

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 used outdoors, a sealing structure for waterproofing and dustproofing is required.

[0003] In the sealing structure of the housing, a liquid gasket may be used. In order to improve the sealing performance in the sealing structure using a liquid gasket, it is important to suppress the movement of the liquid gasket and ensure the contact area between the liquid gasket and the housing.

[0004] Japanese Patent Application Laid-Open No. 2017-152165

[0005] Here, there is a demand for a power storage module that can be used under a wider range of conditions and has better performance.

[0006] Therefore, an object of the present disclosure is to provide a power storage module capable of improving performance.

[0007] 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 arranged in a first direction, the first housing and the second housing are sealed by a sealing structure, the sealing structure includes a first groove portion provided on a first contact surface of the first housing with the second housing, a ridge-shaped protrusion provided on a second contact surface of the second housing with the first housing and accommodated in the groove portion, and a liquid gasket provided between the first groove portion and the protrusion, and a second groove portion is formed on an end surface of the protrusion facing the first groove portion, and the liquid gasket is accommodated in the second groove portion.

[0008] According to the power storage module of the present disclosure, the performance can be improved.

[0009] This is a schematic cross-sectional view showing an energy storage module, which is an example of an embodiment. This is a cross-sectional view showing an energy storage device according to an embodiment. This is a schematic cross-sectional view showing a sealing structure, which is an example of an embodiment. This is a schematic cross-sectional view showing a sealing structure, which is another example of an embodiment. This is a schematic cross-sectional view showing a sealing structure, which is another example of an embodiment. This is a schematic cross-sectional view showing a sealing structure, which is another example of an embodiment.

[0010] An example of an embodiment of this disclosure will be 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.

[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, each component may be described using the upper or lower axial side of the energy storage device 20 housed in the energy storage module 10.

[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 may be arranged so that the closest energy storage devices 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 an upper holder 41 and a lower 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 upper holder 41 and the lower holder 42 are fixed to each other via a fixing member or using locking parts provided on each holder.

[0017] The upper holder 41 has a plurality of housing sections 43, which are cylindrical recesses that accommodate 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 41. Each of the plurality of housing sections 43 has a through hole that forms an opening on the upper surface of the upper holder 41, 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.

[0018] The lower holder 42 has a plurality of housing sections 44, 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 42. Each of the plurality of housing sections 44 has a through hole that forms an opening on the lower surface of the lower holder 42, and a plurality of leads of the positive electrode current collector plates and negative electrode current collector plates may be inserted through this opening and connected to the sealing body 26 or the outer casing 25.

[0019] The housing 50 houses the holder 40. The housing 50 is divided in the vertical direction (first direction) into an upper housing 51 (second housing) and a lower housing 52 (first housing). In this disclosure, the housing may also be divided in the left-right direction or the front-back direction. 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 upper housing 51 has a plate-shaped first base, an annular first wall extending vertically from the first base, and a housing portion 53 in which the upper part of the holder 40 is housed. The lower housing 52 has a plate-shaped second base, an annular second wall extending vertically from the second base, and a housing portion 54 in which the lower part of the holder 40 is housed. In the housing 50, the upper housing 51 and the lower housing 52 are fixed together by a fixing structure (not shown). The fixing structure may be a fixing structure using fastening members such as screws and bolts, or it may be a structure in which an engaging portion and a claw portion are engaged. In addition, in the housing 50, the upper housing 51 and the lower 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] However, 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 may be electrically connected, and a terminal member connected to the positive electrode as a first terminal may be placed in an insertion hole formed in the bottom of the outer casing in an insulated state 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 Figure 3.

[0027] As described above, the sealing structure 60 seals the upper housing 51 and the lower housing 52, thereby sealing the housing 50. The sealing structure 60 makes it possible to improve the energy density of the energy storage module 10 while maintaining the sealing performance of the sealing structure 60 on the housing 50. This makes it possible to improve the performance of the energy storage module 10.

[0028] The sealing structure 60 includes a ridge-shaped projection 61 provided on the contact surface 51A (second contact surface) of the upper housing 51 with the lower housing 52, a first groove 62 provided on the contact surface 52A (first contact surface) of the lower housing 52 with the upper housing 51, which accommodates the projection 61, and a liquid gasket 65 provided between the projection 61 and the first groove 62. The projection 61 is positioned in the width direction so as to be sandwiched between a pair of second regions on the contact surface 51A. The first groove 62 is positioned so as to be sandwiched between a pair of first regions on the contact surface 52A. The pair of first regions and the pair of second regions come into contact with each other, thereby enclosing the space between the projection 61 and the first groove 62. In the energy storage module of this disclosure, the pair of first regions and the pair of second regions do not necessarily have to be in contact with each other.

[0029] In the following, the direction along the projection 61 or the first groove 62 may be described as the depth direction. Also, the direction perpendicular to the depth direction in the horizontal plane may be described as the width direction.

[0030] The projection 61 is formed to protrude downward on the contact surface 51A of the upper housing 51 with the lower housing 52. The projection 61 may be formed approximately in the center of the contact surface 51A in the width direction of the contact surface 51A. The projection 61 is formed along the edge of the housing portion 53 of the upper housing 51. The projection 61 is formed in a rectangular shape in a cross-sectional view along the vertical direction (a cross-sectional view perpendicular to the depth direction). A second groove 63, which will be described in detail later, is formed on the tip surface 61A of the projection, facing the bottom surface 62A of the first groove 62.

[0031] The first groove 62 is formed so as to be recessed downward on the contact surface 52A of the lower housing 52 with the upper housing 51. The first groove 62 may be formed approximately in the center in the width direction of the contact surface 52A. The first groove 62 is formed along the edge of the housing portion 54 of the lower housing 52. The first groove 62 is formed in a rectangular shape in a cross-sectional view along the vertical direction.

[0032] A projection 61 is housed in the first groove 62. The projection 61 is housed in the first groove 62 such that there is a gap between the first groove 62 and the projection 61 in the vertical direction and in the width direction (second direction) perpendicular to the vertical direction. A liquid gasket 65 is also provided inside the first groove 62. Preferably, the liquid gasket 65 is provided in close contact with the bottom surface 62A (first bottom surface) of the first groove 62 or the inner surface 62B (first inner surface) of the first groove 62 that extends in the vertical direction.

[0033] The first groove 62 can suppress the movement of the liquid gasket 65. The first groove 62 can also increase the contact area between the lower housing 52 and the liquid gasket 65. This improves the sealing performance of the sealing structure 60. Furthermore, by providing the second groove 63 on the end face of the protrusion 61, when the protrusion 61 is inserted into the first groove 62, a portion of the liquid gasket in the first groove 62 enters the limited space in the second groove 63, and the pressure generated within the second groove 63 by the filling of the viscous liquid gasket can seal the inner surface of the second groove 63.

[0034] As described above, the second groove 63 is formed so as to be recessed upward on the tip surface 61A of the projection 61. The second groove 63 may be formed approximately in the center in the width direction of the tip surface 61A. The second groove 63 is formed along the projection 61. The second groove 63 is formed in a rectangular shape in a cross-sectional view along the vertical direction. A liquid gasket 65 is provided in the second groove 63. Preferably, the liquid gasket 65 is provided in close contact with the bottom surface 63A (second bottom surface) of the second groove 63 or the inner surface 63B (first inner surface) of the second groove 63 that extends in the vertical direction.

[0035] The second groove 63 bites into the upper part of the liquid gasket 65, suppressing the movement of the liquid gasket 65. Furthermore, the second groove 63 increases the contact area (sealing area) between the upper housing 51 and the liquid gasket 65. This improves the sealing performance of the sealing structure 60.

[0036] Here, the movement of the liquid gasket 65 can be suppressed by sandwiching it between the first groove 62 and the second groove 63. This improves the sealing performance of the sealing structure 60.

[0037] Furthermore, by adopting the above configuration, sufficient sealing performance can be maintained even when the widthwise size of the sealing structure 60 is reduced. In other words, even when the volume of the base and wall portions surrounding the housing space of the housing 50 (upper housing 51 and lower housing 52) is reduced, the sealing performance of the sealing structure 60 of the housing 50 can be maintained. As a result, the energy density of the energy storage module 10 can be improved while maintaining the sealing performance of the sealing structure 60 of the housing 50. This improves the performance of the energy storage module 10.

[0038] 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.

[0039] The liquid gasket 65 is provided in close contact with the bottom surface 62A of the first groove 62. The liquid gasket 65 may also be provided in close contact with the bottom surface 63A and inner surface of the second groove 63. Alternatively, the liquid gasket 65 is provided in the second groove 63. The liquid gasket 65 may also be provided in close contact with the bottom surface 63A and inner surface of the second groove 63.

[0040] [Other Embodiments] Using Figure 4, we will describe another example of the embodiment, a sealing structure 60.

[0041] As shown in Figure 4(A), in the sealing structure 60, the second groove 63 may be formed in a trapezoidal shape in a cross-sectional view along the vertical direction (a cross-sectional view perpendicular to the depth direction). As shown in Figure 4(B), in the sealing structure 60, the second groove 63 may be formed in a trapezoidal triangular shape in a cross-sectional view along the vertical direction. As shown in Figure 4(C), in the sealing structure 60, the second groove 63 may be formed in a semicircular shape in a cross-sectional view along the vertical direction. Even in these cases, the same effects as described above can be obtained.

[0042] [Summary] The present invention is further described by the following embodiments. Configuration 1: A power 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 arranged in a first direction, the first housing and the second housing are sealed by a sealing structure, the sealing structure having a first groove provided on the first contact surface of the first housing with the second housing, a ridge-shaped projection provided on the contact surface of the second housing with the first housing and housed in the first groove, and a liquid gasket provided between the first groove and the projection, a second groove formed on the end face of the projection opposite to the first groove, and the liquid gasket housed in the second groove, the power storage module. Configuration 2: A power storage module according to Configuration 1, wherein the first contact surface has a pair of first regions arranged to sandwich the first groove in a second direction perpendicular to the first direction, and the second contact surface has a pair of second regions arranged to sandwich the protrusion in the second direction. Configuration 3: A power storage module according to Configuration 1, wherein the first housing has a plate-shaped first base and an annular first wall extending from the first base in the first direction, and the first contact surface is provided on the first wall; the second housing has a plate-shaped second base and an annular second wall extending from the second base in the first direction, and the second contact surface is provided on the second wall. Configuration 4: A power storage module according to any one of Configurations 1 to 3, wherein the cross-sectional view of the second groove is trapezoidal, triangular, or semicircular.

[0043] 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.

[0044] 10 Energy storage module, 20 Energy storage device, 21 Positive electrode, 22 Negative electrode, 23 Separator, 24 Electrode group, 25 Outer can, 25A Groove, 26 Sealing body, 27 Positive electrode lead, 28 Negative electrode lead, 29 Gasket, 30 Insulating plate, 40 Holder, 41 Upper holder, 42 Lower holder, 43 Housing section, 44 Housing section, 50 Housing, 51 Upper housing, 51A Contact surface, 52 Lower housing, 52A Contact surface, 60 Sealing structure, 61 Protrusion, 61A Tip surface, 62 First groove, 62A Bottom surface, 62B Inner surface, 63 Second groove, 63A Bottom surface, 63B Inner surface, 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 arranged in a first direction, the first housing and the second housing are sealed by a sealing structure, the sealing structure having a first groove provided on the first contact surface of the first housing with the second housing, a ridge-shaped projection provided on the second contact surface of the second housing with the first housing and housed in the first groove, and a liquid gasket provided between the first groove and the projection, a second groove formed on the end face of the projection opposite to the first groove, and the liquid gasket housed in the second groove, the energy storage module.

2. An energy storage module according to claim 1, wherein the first contact surface has a pair of first regions arranged to sandwich the first groove in a second direction perpendicular to the first direction, and the second contact surface has a pair of second regions arranged to sandwich the protrusion in the second direction.

3. An energy storage module according to claim 1, wherein the first housing has a plate-shaped first base and an annular first wall extending from the first base in a first direction, and the first contact surface is provided on the first wall; and the second housing has a plate-shaped second base and an annular second wall extending from the second base in a first direction, and the second contact surface is provided on the second wall.

4. An energy storage module according to any one of claims 1 to 3, wherein the cross-sectional view of the second groove is trapezoidal, triangular, or semicircular.

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