Energy storage module

Abstract

We provide energy storage modules with superior reliability. [Solution] The device comprises at least one cylindrical energy storage device 20, an upper holder 30 for holding the energy storage device 20, and an insulating plate 80 provided on the upper side of the upper holder 30. An exhaust valve 15 is provided at the upper end of the energy storage device 20, and an opening 32 is formed in the upper holder 30 to expose the exhaust valve 15. The insulating plate 80 has a flat main body portion 81, an opening 82 formed in the main body portion 81 and communicating with the opening 32, a cover portion 83 that covers a part of the opening 82, and a connecting portion 84 that connects the cover portion 83 and the main body portion 81. The main body portion 81 is provided with a fixing portion 85 for fixing the insulating plate 80 and the upper holder 30.

Description

Technical Field

[0001] This disclosure relates to a power storage module.

Background Art

[0002] The power storage module has at least one cylindrical power storage device and an exhaust duct for discharging the gas released from the power storage device to the outside of the power storage module when the power storage device malfunctions.

[0003] In the power storage module disclosed in Patent Document 1, a flat plate (hereinafter referred to as an insulating plate) that partitions the exhaust duct is provided above a holder that holds the upper side of the power storage device. An opening valve that opens only toward the exhaust duct is formed in the insulating plate. Thus, when the power storage device malfunctions, the opening valve is opened by the pressure of the gas released from the power storage device, and the gas flows into the exhaust duct and is discharged to the outside of the power storage module.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The reliability of the power storage module in Patent Document 1 can be improved. However, further improvement in the reliability of the power storage module is required.

[0006] An object of this disclosure is to provide a power storage module having excellent reliability.

Means for Solving the Problems

[0007] An energy storage module according to one aspect of the present disclosure comprises at least one cylindrical energy storage device, a holder for holding the energy storage device, and an insulating plate provided on one side of the holder, wherein an exhaust valve is provided at one end of the energy storage device, a first opening is formed in the holder to expose the exhaust valve, the insulating plate has a flat main body, a second opening formed in the main body and communicating with the holder opening, a cover that closes a part of the insulating plate opening, and a connecting part that connects the cover and the main body, and the main body is provided with a fixing part for fixing the insulating plate and the holder. [Effects of the Invention]

[0008] According to one aspect of this disclosure, the reliability of the energy storage module is improved. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side cross-sectional view showing an energy storage module according to an embodiment. [Figure 2] This is a detailed view of section A in Figure 1. [Figure 3] This is a plan view showing an insulating plate. [Figure 4] This is a perspective view showing a portion of the insulating board. [Figure 5] This is a plan view showing an insulating plate according to another embodiment. [Figure 6] This is a plan view showing an insulating plate according to another embodiment. [Figure 7] This is a plan view showing an insulating plate according to another embodiment. [Figure 8] This is a plan view showing an insulating plate according to another embodiment. [Figure 9] This is a plan view showing an insulating plate according to another embodiment. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described below with reference to the drawings. The shapes, materials, and quantities described below are illustrative and can be appropriately changed according to the specifications of the energy storage module.

[0011] "Energy storage module" The energy storage module 10 according to an embodiment will be described with reference to Figures 1 and 2.

[0012] The energy storage module 10 is primarily used as a power source. For example, the energy storage module 10 is used as a power source for motor-driven equipment such as electric vehicles, power tools, electric assist bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the applications of the energy storage module 10 are not limited, and it may also be used as a power source for various electrical devices used indoors and outdoors, such as cleaners, wireless devices, lighting devices, digital cameras, and video cameras.

[0013] In Figure 1, the energy storage module 10 comprises a plurality of cylindrical energy storage devices 20, an upper holder 30 which holds the upper end of each of the plurality of energy storage devices 20, a current collecting member 40 which collects current from the first terminal (positive terminal) and the second terminal (negative terminal) of the energy storage device 20, and a lower holder 50 which holds the lower end of each of the plurality of energy storage devices 20.

[0014] Furthermore, the energy storage module 10 includes a case 60 as an enclosure for housing the energy storage device 20, upper holder 30, current collector 40, and lower holder 50; an exhaust duct 70 that communicates with the outside of the case 60 from the upper side of the inside of the case 60; and an insulating plate 80 that partitions the lower side of the exhaust duct 70 and insulates the exhaust duct 70 from the energy storage device 20.

[0015] "Energy storage device" The energy storage device 20 uses a cylindrical lithium-ion secondary battery. The energy storage device 20 is not limited to a lithium-ion secondary battery, but may also be a nickel-metal hydride battery, a capacitor, or the like.

[0016] In FIG. 2, in the power storage device 20, although details will be described later, a positive electrode terminal as the first terminal and a negative electrode terminal as the second terminal are arranged at the upper end portion. More specifically, the positive electrode terminal is formed on the top surface of a sealing body 26 described later. Further, the negative electrode terminal is formed at the caulked opening end portion (hereinafter referred to as the shoulder portion 25C) of an outer can 25 described later.

[0017] The plurality of power storage devices 20 are filled most densely in the power storage module 10 in consideration of safety, and adjacent power storage devices 20 may be arranged almost close to each other. In the power storage device 20, for example, in a plan view, six power storage devices 20 are arranged to surround one power storage device 20 (hereinafter referred to as a staggered arrangement).

[0018] The power 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 interposed therebetween, a cylindrical outer can 25 that houses the electrode group 24 together with an electrolytic solution, a sealing body 26 that seals the opening of the outer can 25 in an insulated state, a foil-shaped positive electrode tab 27 that electrically connects the positive electrode 21 and the sealing body 26, and a negative electrode tab (not shown) that electrically connects the negative electrode 22 and the outer can 25. An insulating gasket 28 is arranged between the outer periphery of the sealing body 26 and the inner peripheral surface of the opening of the outer can 25.

[0019] An annular groove portion 25A is formed on the outer peripheral surface of the outer can 25 on the opening side. An annular convex portion 25B is formed on the inner peripheral surface of the corresponding outer can 25. The gasket 28 and the sealing body 26 are arranged on the annular convex portion 25B inside the outer can 25. Further, the shoulder portion 25C of the outer can 25 is caulked so as to fall inward of the outer can 25 with the gasket 28 arranged on the inner peripheral side. The caulked shoulder portion 25C and the convex portion 25B sandwich the sealing body 26 in the vertical direction via the gasket 28, thereby sealing the opening of the outer can 25. The exhaust valve 15 may be formed at the bottom of the outer can 25. In this case, an opening is formed in a lower holder 50 that supports the bottom side of the outer can 25, and an insulating plate is arranged on the outer bottom surface of the lower holder 50.

[0020] The sealing body 26 may be provided with a current interruption mechanism (CID) and an exhaust valve 15 (not shown) that ruptures when the pressure inside the outer can 25 exceeds a predetermined level. An insulating member 29 may also be provided between the electrode group 24 and the protrusion 25B to insulate the electrode group 24 from the outer can 25. If an insulating member 29 is provided, the positive electrode tab 27 may extend through a through hole formed in the insulating member 29. Furthermore, an insulating member may be provided between the electrode group 24 and the bottom of the outer can 25 to insulate the electrode group 24 from the outer can 25. The negative electrode tab may extend either through a through hole formed in the insulating member or by bypassing the insulating member.

[0021] In the energy storage device 20, as described above, the positive terminal is located on the top surface of the sealing body 26, and the positive lead 41 of the current collector member 40, which will be described later, is joined to it. Also, in the energy storage device 20, as described above, the negative terminal is located on the crimped shoulder portion 25C of the outer casing 25, and the negative lead (not shown) of the current collector member 40, which will be described later, is joined to the shoulder portion 25C of the outer casing 25 from the radially outer side of the energy storage device 20.

[0022] "Upper holder" The upper holder 30 is a component that holds the upper end sides of multiple energy storage devices 20. The upper holder 30 is made of thermoplastic resin. Thermoplastic resins are broadly classified into general-purpose plastics and engineering plastics, and polyethylene, polypropylene, polyamide, ABS, etc., are used.

[0023] In Figure 2, the bottom surface of the upper holder 30 has multiple housing sections 31 formed therein, each housing the upper end of the respective energy storage device 20. The upper end of the energy storage device 20 is held in the upper holder 30 by fitting it into the housing section 31.

[0024] A circular opening 32 (first opening) is formed in the ceiling of the housing section 31. Through the opening 32, the top surface of the sealing body 26 of the energy storage device 20 is exposed from the upper surface of the upper holder 30. Therefore, the top surface of the sealing body 26 can be joined to the positive electrode lead 41 through the opening 32. In addition, in the event of a malfunction of the energy storage device 20, high-temperature gas or high-temperature conductive ejecta released from the exhaust valve 15 of the energy storage device 20 can be released above the upper holder 30. Note that the shape of the opening 32 is not limited to a circle. It may be elliptical, oblong, rectangular, or polygonal.

[0025] "Current collector component" In Figure 2, the current collector 40 is formed from a plate-shaped metal material (metal foil) and is provided on the top surface of the upper holder 30. The current collector 40 has a base, an opening formed in the base (a third opening), a positive lead 41 extending from the inner periphery of this opening and connected to the positive terminal of the energy storage device 20, and a negative lead (not shown) connected to the negative terminal of the energy storage device 20. The current collector 40 does not necessarily have an opening. The positive lead 41 or the negative lead may extend from the outer edge of the current collector 40. The current collector 40 may have a current collector member that connects to the positive terminal and a current collector member that connects to the negative terminal of the energy storage device 20, both arranged on the top surface of the upper holder 30, and a current collector plate connected to one of the terminals may be provided on the outer bottom surface of the lower holder 50. In this case, the lower holder 50 may also have an opening that exposes the energy storage device 20 from the housing portion of each energy storage device 20. The lead of one electrode may be inserted through the opening of the lower holder 50.

[0026] "Lower holder" In Figure 1, the lower holder 50 is a component that holds the lower ends of multiple energy storage devices 20. The lower holder 50 is made of thermoplastic resin. Thermoplastic resins are broadly classified into general-purpose plastics and engineering plastics, and polyethylene, polypropylene, polyamide, ABS, etc., are used.

[0027] "case" In Figures 1 and 2, the case 60 houses the energy storage device 20, the upper holder 30, the current collector 40, and the lower holder 50. An exhaust duct 70, which will be described later, is partitioned off in the upper part of the case 60.

[0028] "Exhaust duct" In Figures 1 and 2, the exhaust duct 70 discharges gas from inside the energy storage device 20 to the outside of the case 60 in the event of a malfunction in the energy storage device 20. The exhaust duct 70 is a duct formed from an insulating plate 80 (described later) and the case 60 located above the insulating plate 80. The exhaust duct 70 has an exhaust port 71 that communicates with the outside of the case 60. Note that in the energy storage module 10 of this disclosure, the case 60 or the exhaust duct 70 are not essential.

[0029] "Insulating board" The insulating plate 80 will be described in detail with reference to Figures 2 to 4.

[0030] The insulating plate 80 partitions the exhaust duct 70 and insulates the exhaust duct 70 from the energy storage device 20. The insulating plate 80 is made of mica, glass epoxy, and flame-retardant fiber.

[0031] The insulating plate 80 has a flat main body portion 81, an opening 82 formed in the main body portion 81 and communicating with the opening 32, a cover portion 83 that covers a part of the opening 82, and a connecting portion 84 that connects the cover portion 83 and the main body portion 81. In addition, a fixing portion 85 is provided near the connecting portion 84 of the main body portion 81 for fixing the insulating plate 80 and the upper holder 30.

[0032] The main body 81 is a flat, rectangular plate in plan view and is in contact with the top surface of the current collector 40. The main body 81 partitions the exhaust duct 70 and insulates the exhaust duct 70 from the energy storage device 20. The main body 81 is also fixed to the upper holder 30 by a fixing device 90 at a fixing part 85, which will be described in detail later.

[0033] The opening 82 is formed in the main body 81 and is circular in shape, communicating with the opening 32 of the upper holder 30 and the opening of the current collector 40. The openings 82 are arranged in a staggered pattern to match the arrangement of the openings 32 in a plan view, in other words, the arrangement of the energy storage device 20. The shape of the opening 82 is not limited to a circular shape. It may be an elliptical, oblong, rectangular, or other polygonal shape. It is preferable that the shape follows the shape of the opening 32.

[0034] The opening 82 allows the top surface of the sealing body 26 of the energy storage device 20 to be exposed from the upper surface of the insulating plate 80. Therefore, if high-temperature gas or conductive ejecta (hereinafter also referred to as discharged material) is released from inside the energy storage device 20 in the event of a malfunction in the energy storage device 20, these discharged material can be released above the insulating plate 80.

[0035] As described above, the lid portion 83 covers a part of the opening 82. In this example, the lid portion 83 is formed in a circular shape. The lid portion 83 is formed with a diameter smaller than the diameter of the opening 82, and a predetermined gap is formed between the edge of the lid portion 83 and the edge of the opening 82.

[0036] The lid 83 opens due to the pressure of gas released from the energy storage device 20 when the energy storage device 20 malfunctions, allowing the discharged material from the energy storage device 20 to escape above the insulating plate 80. On the other hand, when another energy storage device 20 malfunctions, it prevents the discharged material from the malfunctioning energy storage device 20 in the exhaust duct 70 from flowing into the normally functioning energy storage device 20 through the opening 82.

[0037] The connecting portion 84 connects the lid portion 83 and the main body portion 81. The connecting portion 84 is formed, for example, in the shape of a strip, and connects the edge of the lid portion 83 to the edge of the opening 82. The connecting portion 84 does not have to be in the shape of a strip. In this example, one connecting portion 84 is formed for each lid portion 83. With the connecting portion 84, when the lid portion 83 opens due to the pressure of the gas released from inside the energy storage device 20 in the event of a malfunction in the energy storage device 20, the connecting portion 84 will break or plastically deform, and the lid portion 83 can be maintained in the open state.

[0038] The fixing portion 85 secures the insulating plate 80 and the upper holder 30 in the main body portion 81. The fixing portion 85 may be provided in the main body portion 81 on the side opposite to the side where the cover portion 83 is provided, with the end of the connecting portion 84 on the main body portion side as the boundary. The insulating plate 80 can be more securely fixed if the fixing portion 85 overlaps with the connecting portion 84 in the direction in which the connecting portion 84 extends. If the connecting portion 84 extends in multiple directions, the direction in which the connecting portion 84 extends is the direction in which the connecting portion 84 closest to the end on the main body portion side extends. In this example, one fixing portion 85 is provided for each connecting portion 84. The insulating plate 80 and the upper holder 30 are fixed in the fixing portion 85 by a fixing device 90, which will be described later.

[0039] The fixing part 85 prevents the insulating plate 80 from lifting off the upper holder 30 due to the pressure of the gas released from inside the energy storage device 20 in the event of a malfunction in the energy storage device 20. Furthermore, when the lid portion 83 and the connecting portion 84 lift off due to the pressure of the gas released from inside the energy storage device 20 in the event of a malfunction in the energy storage device 20, the main body portion 81 is pulled upward via the connecting portion 84. By providing the fixing part 85 near the connecting portion 84, it is possible to more effectively prevent the insulating plate 80 from lifting off the upper holder 30.

[0040] The fastener 90 secures the insulating plate 80 and the upper holder 30 at the fixing portion 85. In this example, resin rivets are preferably used for the fastener 90, but are not limited thereto. Fastening and fixing with screws, adhesive or tape, welding and fixing with thermoplastic resin, or snap-fit ​​fixing of resin members are also possible.

[0041] When the energy storage device 20 malfunctions and gas is released from inside the device, the gas will be ejected from the opening 82, and the pressure of the gas will lift the lid 83, causing the connecting part 84 to break or undergo plastic deformation. At this time, since the main body 81 is fixed to the upper holder 30 by the fixing part 85, the main body 81 will not lift off the upper holder 30.

[0042] At the same time, the high-temperature gas or high-temperature conductive ejected material released from the energy storage device 20 is discharged into the exhaust duct 70 and out of the case 60 through the exhaust port 71. At this time, since the opening 82 above the other energy storage device 20 is blocked by the cover 83, it is possible to prevent the high-temperature gas or ejected material in the exhaust duct 70 from flowing into the energy storage device 20 through the opening 82.

[0043] The insulating plate 80 prevents the insulating plate 80 from lifting off the upper holder 30 due to the pressure of gas released from inside the energy storage device 20 in the event of a malfunction in the energy storage device 20. As a result, high-temperature gas or high-temperature conductive ejected material released from inside the energy storage device 20 does not get trapped under the insulating plate 80 and cause other energy storage devices 20 to catch fire.

[0044] "Modified Examples of Insulating Boards" Modified examples of the insulating plate 80 will be described using Figures 5 to 9. In the following description, elements equivalent to those in the embodiments described above will be denoted by the same reference numerals.

[0045] In Figure 5, the insulating plate 80 is provided with one fixing part 85 for multiple connection parts 84. Specifically, there may be cases where one fixing part 85 is provided at the end of two connection parts 84, or where one fixing part 85 is provided at the end of three connection parts 84. With this configuration, the number of fixing parts 85 required in the insulating plate 80 is reduced by sharing the fixing parts 85, and miniaturization of the insulating plate 80 and the energy storage module 10 can be expected.

[0046] In Figure 6, multiple connection parts 84 are formed on the insulating plate 80 relative to the cover portion 83. Specifically, two connection parts 84 are formed on one cover portion 83, but three connection parts 84 may be formed on one cover portion 83. When multiple connection parts 84 are formed on one cover portion 83 in this way, when an abnormal energy storage device 20 discharges waste, some of the multiple connection parts 84 may rupture due to the pressure of the high-temperature gas, or depending on the material of the insulating plate 80, the cover portion 83 or the connection parts 84 may stretch, allowing the waste to be discharged into the exhaust duct 70. With this configuration, even if there is no abnormal energy storage device 20, or if an abnormal energy storage device 20 occurs, the energy storage device 20 in a normal state can be more reliably protected by the cover portion 83.

[0047] In Figure 7, the lid portion 83 of the insulating plate 80 is formed in a triangular shape and covers a part of the opening 82.

[0048] In Figure 8, the insulating plate 80 has a rectangular cover portion 83 that covers a part of the opening 82.

[0049] In Figure 9, the multiple energy storage devices 20 are arranged in a aligned state in a plan view (hereinafter referred to as aligned arrangement). In the insulating plate 80, the openings 82 are arranged in an aligned state according to the arrangement of the openings 32 in a plan view, in other words, the arrangement of the energy storage devices 20.

[0050] It should be noted that the present invention 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.

[0051] In this embodiment, the example was described in which the exhaust valves 15 of each of the multiple energy storage devices 20 are arranged facing the same direction, but the energy storage module 10 of this disclosure is not limited to this configuration. For example, among the multiple energy storage devices 20, some of the energy storage devices 20 may have their exhaust valves 15 facing the upper holder side, while the exhaust valves 15 of the remaining energy storage devices 20 may face the lower holder side. In this case, the insulating plates in the energy storage module 10 may be arranged on both the upper holder and the lower holder sides, respectively. [Explanation of symbols]

[0052] 10 Energy storage module, 15 Exhaust valve, 20 Energy storage device, 21 Positive electrode (first electrode), 22 Negative electrode (second electrode), 23 Separator, 24 Electrode group, 25 Outer casing, 25A Groove, 25B Protrusion, 25C Shoulder, 26 Sealing body, 27 Positive electrode tab, 28 Gasket, 29 Insulating member, 30 Upper holder, 31 Housing section, 32 Opening (first opening), 40 Current collector, 41 Positive electrode lead, 50 Lower holder, 60 Case, 70 Exhaust duct, 71 Exhaust port, 80 Insulating plate, 81 Main body, 82 Plate opening (second opening), 83 Lid, 84 Connection section, 85 Fixing section, 90 Fixing device

Claims

1. The device comprises at least one cylindrical energy storage device, a holder for holding the energy storage device, and an insulating plate provided on one side of the holder. An exhaust valve is provided at one end of the aforementioned energy storage device. The holder has a first opening that exposes the exhaust valve. The insulating plate has a flat main body, a second opening formed in the main body and communicating with the first opening, a cover portion that closes a part of the second opening, and a connecting portion that connects the cover portion and the main body. The main body is provided with a fixing portion for fixing the insulating plate and the holder. The fixing portion overlaps with the connecting portion in the direction in which the connecting portion extends. Energy storage module.

2. The device comprises at least one cylindrical energy storage device, a holder for holding the energy storage device, and an insulating plate provided on one side of the holder. An exhaust valve is provided at one end of the aforementioned energy storage device. The holder has a first opening that exposes the exhaust valve. The insulating plate has a flat main body, a second opening formed in the main body and communicating with the first opening, a cover portion that closes a part of the second opening, and a connecting portion that connects the cover portion and the main body. The main body is provided with a fixing portion for fixing the insulating plate and the holder. The aforementioned connecting portion is formed in the shape of a strip, Energy storage module.

3. The device comprises at least one cylindrical energy storage device, a holder for holding the energy storage device, and an insulating plate provided on one side of the holder. An exhaust valve is provided at one end of the aforementioned energy storage device. The holder has a first opening that exposes the exhaust valve. The insulating plate has a flat main body, a second opening formed in the main body and communicating with the first opening, a cover portion that closes a part of the second opening, and a connecting portion that connects the cover portion and the main body. The main body is provided with a fixing portion for fixing the insulating plate and the holder. The insulating plate has multiple connection portions for one of the lid portions. Energy storage module.

4. The device comprises at least one cylindrical energy storage device, a holder for holding the energy storage device, and an insulating plate provided on one side of the holder. An exhaust valve is provided at one end of the aforementioned energy storage device. The holder has a first opening that exposes the exhaust valve. The insulating plate has a flat main body, a second opening formed in the main body and communicating with the first opening, a cover portion that closes a part of the second opening, and a connecting portion that connects the cover portion and the main body. The main body is provided with a fixing portion for fixing the insulating plate and the holder. The system comprises multiple of the aforementioned energy storage devices, A single fixing portion is provided for each of the multiple adjacent connecting portions. Energy storage module.

5. The device comprises at least one cylindrical energy storage device, a holder for holding the energy storage device, and an insulating plate provided on one side of the holder. An exhaust valve is provided at one end of the aforementioned energy storage device. The holder has a first opening that exposes the exhaust valve. The insulating plate has a flat main body, a second opening formed in the main body and communicating with the first opening, a cover portion that closes a part of the second opening, and a connecting portion that connects the cover portion and the main body. The main body is provided with a fixing portion for fixing the insulating plate and the holder. The lid portion is formed in a circular, triangular, or rectangular shape. Energy storage module.

6. A storage module according to any one of claims 1 to 5, At least one of the energy storage devices comprises an electrode group including a first electrode and a second electrode, an outer container housing the electrode group, and a sealing body that closes the opening of the outer container together with a gasket, wherein the first electrode is electrically connected to the sealing body, and the second electrode is electrically connected to the outer container. Energy storage module.

7. The energy storage module according to claim 6, The exhaust valve is provided in the sealing body, Energy storage module.

8. The energy storage module according to claim 6, Between the holder and the insulating plate, there is further a current collector member that electrically connects the multiple energy storage devices. The current collector member has a base, a third opening formed in the base and overlapping the first and second openings, and a lead portion extending from the inner edge of the third opening and electrically connected to the sealing body or the outer can. Energy storage module.

9. A storage module according to any one of claims 1 to 5, The system further comprises a housing that accommodates the energy storage device, the holder, and the insulating plate, and an exhaust duct that is partitioned by the insulating plate on one side of the housing and communicates with the outside of the housing. Energy storage module.

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