Power storage device and power storage module

Abstract

The present disclosure relates to a power storage device and a power storage module including the same, and provides a power storage device in which the strength of an exterior body is improved. A power storage device disclosed herein is provided with: an electrode assembly having a positive electrode and a negative electrode; and a metal outer packaging body (10), wherein the electrode body is accommodated in the metal outer packaging body (10). Fibers (60), which are continuous so as to cover the outer peripheral side surface, are wound around the exterior body (10) so as to be aligned in a preset direction.

Description

Technical Field

[0001] This disclosure relates to energy storage devices and energy storage modules that include such energy storage devices. Background Technology

[0002] International Publication No. WO2018 / 168549 discloses an all-solid-state secondary battery comprising: a cylindrical battery element component having a current collector, a solid electrolyte layer, and a positive electrode active material layer; a core having the battery element component disposed on its outer periphery; and a battery casing housing the battery element component and the core. The outer periphery of the battery casing of this all-solid-state secondary battery has a reinforcing cover. This reinforcing cover is configured to press the battery casing inward with a compressive stress of 0.5 MPa or more between the core and the battery element component, and between the battery casing and the battery element component. This suppresses expansion of the battery casing.

[0003] Furthermore, Japanese Patent Application Publication No. 2020-155356 discloses a method for manufacturing a housing, in which resin-impregnated carbon fibers are wound in a manner that follows a mold (mandrel) for the housing. The housing manufactured by this method is made of fiber-reinforced plastic and possesses elasticity. The narrow side of the housing is the contact portion that contacts the laminated electrode body. Additionally, the wide side of the housing has a spring structure connecting to this contact portion.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. WO2018 / 168549

[0007] Patent Document 2: Japanese Patent Application Publication No. 2020-155356 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Energy storage devices such as lithium-ion rechargeable batteries expand during charging and discharging. The inventors sought to suppress this expansion of the energy storage device.

[0010] Methods for solving problems

[0011] The energy storage device disclosed herein includes: an electrode body having a positive electrode and a negative electrode; and a metal outer casing housing the electrode body. Continuous fibers, covering the outer peripheral side, are wound around the outer casing in a predetermined direction.

[0012] This energy storage device can suppress the expansion of the energy storage device. In addition, it can improve the strength of the outer casing. Attached Figure Description

[0013] Figure 1 It is a schematic 3D view of a lithium-ion secondary battery.

[0014] Figure 2 From and Figure 1 A schematic 3D diagram of a lithium-ion secondary battery viewed from different angles.

[0015] Figure 3 This is a schematic longitudinal sectional view of a lithium-ion secondary battery.

[0016] Figure 4 This is an exploded view of the electrode body (wound electrode body).

[0017] Figure 5 This is a schematic diagram used to illustrate the expanded state of an energy storage device.

[0018] Figure 6 It is a schematic enlarged cross-sectional view used to illustrate the expanded state of an energy storage device.

[0019] Figure 7 This is a schematic top view of a lithium-ion secondary battery viewed from a narrow side.

[0020] Figure 8 This is a schematic top view of a lithium-ion secondary battery viewed from a wide-angle perspective.

[0021] Figure 9 This is an illustrative diagram illustrating a method of winding fibers into a lithium-ion secondary battery.

[0022] Figure 10 This is a schematic perspective view of an energy storage module, including the energy storage device disclosed herein.

[0023] Figure 11 This is a schematic perspective view of a battery pack housing type energy storage module included in the energy storage device disclosed herein.

[0024] Explanation of reference numerals in the attached figures

[0025] 1. Lithium-ion secondary battery

[0026] 2-layered body

[0027] 10 outer body

[0028] 10a, 10b openings

[0029] 10c Welded joint

[0030] 11. Main body of the shell

[0031] 11a1, 11a2 wide format

[0032] 11b1, 11b2 Narrow format

[0033] 13a, 13b sealing plates

[0034] 14 Positive external terminal

[0035] 15 Negative external terminal

[0036] 16 Positive internal terminals

[0037] 17 Negative internal terminal

[0038] 20 Electrode Body

[0039] 21 Flat surface

[0040] 30 Positive electrode

[0041] 31a Non-forming portion of the positive electrode active material layer

[0042] 31b Positive electrode protective layer

[0043] 31c Positive electrode tab

[0044] 32 Positive electrode active material layer

[0045] 40 Negative electrode

[0046] 41 Negative electrode current collector foil

[0047] 41a Non-forming portion of the negative electrode active material layer

[0048] 41c Negative electrode tab

[0049] 42 Negative electrode active material layer

[0050] 50a and 50b diaphragms

[0051] 60 Fibers

[0052] 61 First Fiber

[0053] 62 Second Fiber

[0054] 70, 80 corner

[0055] 100 energy storage module

[0056] 102 Battery Pack Housing Type Energy Storage Module

[0057] 110 Constraint Members

[0058] 111 base plate

[0059] 112a First end plate

[0060] 112b Second End Plate

[0061] 113 Side bar

[0062] 114 screws

[0063] 120 spacer

[0064] 120a First Spacer

[0065] 120b Second spacer

[0066] 210 Battery Pack Housing

[0067] 211 bottom wall

[0068] 212 Sidewall

[0069] AX central axis

[0070] WL winding shaft

[0071] α angle

[0072] β angle

[0073] θ is the angle. Detailed Implementation

[0074] The energy storage device of this disclosure will now be described in detail. Furthermore, in the accompanying drawings, components and parts that perform the same function are labeled with the same reference numerals and explained. Also, the dimensional relationships (length, width, thickness, etc.) in the drawings do not reflect actual dimensional relationships. The reference numerals L, R, U, D, F, and Rr in the drawings represent the left, right, top, bottom, front, and rear of the lithium-ion secondary battery 1. Furthermore, the left-right direction is defined as X, the top-bottom direction as Y, and the front-back direction as Z. However, these are merely directions for ease of explanation and do not limit the arrangement of the energy storage device (lithium-ion secondary battery 1) in any way.

[0075] <Definitions of Terms>

[0076] In this specification, "energy storage device" is a concept that includes a device that generates a charging and discharging reaction by moving a charge carrier between a pair of electrodes (positive and negative electrodes). That is, an energy storage device includes batteries such as secondary batteries (e.g., lithium-ion secondary batteries, nickel-metal hydride batteries, nickel-cadmium batteries) and capacitors (physical batteries) such as lithium-ion capacitors and double-layer capacitors. Furthermore, the following description uses a lithium-ion secondary battery, as a typical energy storage device, as an example to illustrate this embodiment. Additionally, in this specification, "lithium-ion secondary battery" refers to an energy storage device that uses lithium ions as charge carriers and achieves repeated charging and discharging through the movement of the charge accompanying the lithium ions between the positive and negative electrodes.

[0077] In this specification, when a numerical range is described as "A~B (where A and B are arbitrary values)," it means "above A and below B," and includes meanings such as "above A and less than B," "above A and below B," and "above A and less than B."

[0078] <Electrical Storage Devices: Lithium-ion Secondary Batteries 1>

[0079] Figure 1 This is a schematic three-dimensional view of a lithium-ion secondary battery 1. Figure 2 From and Figure 1 A schematic three-dimensional view of the lithium-ion secondary battery 1 viewed from different angles. Figure 1 and Figure 2 In order to understand the structure of the outer casing 10, a portion of the fiber 60 is removed and displayed. Figure 3 This is a schematic longitudinal sectional view of a lithium-ion secondary battery 1. Figure 3 The text shows along Figure 1 A longitudinal section view along line III-III. Figure 3 In order to understand the structure of the electrode body 20 housed in the outer casing 10, a portion of the electrode body 20 is displayed. Figure 4 This is an exploded view of electrode body 20 (wound electrode body).

[0080] Figures 1-3 The lithium-ion secondary battery 1 shown is a preferred example of the energy storage device disclosed herein. For example... Figures 1-3 As shown, the lithium-ion secondary battery 1 includes an electrode body 20 and an outer casing 10.

[0081] <Electrode 20>

[0082] like Figure 3 and Figure 4As shown, the electrode body 20 has a positive electrode 30 and a negative electrode 40. In this embodiment, the electrode body 20 is a wound electrode body formed by overlapping strip-shaped positive electrodes 30 and strip-shaped negative electrodes 40 along the length direction with strip-shaped separators 50a and 50b in between, and wound around a winding axis WL set along the width direction of the positive electrode 30. In this embodiment, a positive electrode tab 31c is provided at one end of the electrode body 20 in the direction of the winding axis. In addition, a negative electrode tab 41c is provided at the other end in the direction of the winding axis. That is, in this embodiment, a positive electrode tab 31c is provided at one end of the electrode body 20 along the winding axis, and a negative electrode tab 41c is provided at the other end. Furthermore, the electrode body 20 is not limited to a wound electrode body, and may also be a stacked electrode body in which positive and negative electrodes are alternately stacked with separators in between. In addition, in a stacked electrode body, the strip-shaped diaphragm can also be in a so-called multi-folded shape, which is zigzag-shaped while sandwiching the positive and negative electrodes.

[0083] <Positive Electrode 30>

[0084] like Figure 4 As shown, the positive electrode 30 comprises a rectangular positive electrode current collector foil 31 and a positive electrode active material layer 32 formed on the surface of the positive electrode current collector foil 31. The positive electrode active material layer 32 is capable of reversibly attracting and releasing charge carriers (e.g., lithium ions). That is, the positive electrode active material layer 32 contains a positive electrode active material that can release charge carriers during charging and attract charge carriers during discharging. Furthermore, the positive electrode active material layer 32 can be formed on one or both sides (in this case, both sides) of the positive electrode current collector foil 31. Alternatively, the positive electrode 30 may also have a non-formed portion 31a of the positive electrode active material layer where the positive electrode current collector foil 31 is exposed without the formation of the positive electrode active material layer 32. The non-formed portion 31a is provided at one end of the electrode body 20. In this embodiment, a positive electrode protective layer 31b is provided at the edge of the positive electrode active material layer 32 on the positive electrode current collector foil 31 (more specifically, the non-formed portion 31a of the positive electrode active material layer). The positive electrode protective layer 31b is a layer that protects the non-forming portion 31a of the positive electrode active material layer, and it is a layer containing inorganic fillers (such as alumina).

[0085] The material of the positive electrode current collector foil 31 can be any known positive electrode current collector foil used in such energy storage devices, and is not particularly limited. Examples of materials for the positive electrode current collector foil 31 include aluminum or aluminum alloys. The positive electrode active material for the positive electrode active material layer 32 can be any positive electrode active material used in the positive electrode of a typical lithium-ion secondary battery. Examples of lithium composite metal oxides include LiCoO2, LiNiO2, LiFeO2, and LiNiO2. x Co y Mn 1-x-y O2 (NCM), LiNi 0.5Mn 1.5 O4, LiNi 0.8 Co 0.15 Al 0.05 O2 (NCA), LiCrMO4, LiMn2O4, LiFePO4 (LFP), etc. Furthermore, these positive electrode active materials can be used individually or in combination of two or more. Additionally, the positive electrode active material layer 32 may also contain various additives such as binders, conductive additives, inorganic fillers, or thickeners.

[0086] <Negative Electrode 40>

[0087] like Figure 4 As shown, the negative electrode 40 comprises a rectangular negative electrode current collector foil 41 and a negative electrode active material layer 42 formed on the surface of the negative electrode current collector foil 41. The negative electrode active material layer 42 is capable of reversibly adsorbing and releasing charge carriers (e.g., lithium ions). That is, the negative electrode active material layer 42 contains a negative electrode active material that can adsorb charge carriers and release charge carriers during discharge. Furthermore, the negative electrode active material layer 42 can be formed on one or both sides (in this case, both sides) of the negative electrode current collector foil 41. Alternatively, the negative electrode 40 may also have a non-formed portion 41a of the negative electrode active material layer where the negative electrode current collector foil 41 is exposed without the formation of the negative electrode active material layer 42. The non-formed portion 41a of the negative electrode active material layer is provided at one end of the electrode body 20.

[0088] The material of the negative electrode current collector foil 41 can be any known negative electrode current collector foil used in such energy storage devices, and is not particularly limited. Examples of materials for the negative electrode current collector foil 41 include copper or copper alloys. The negative electrode active material of the negative electrode active material layer 42 can be any negative electrode active material used in the negative electrode of a typical lithium-ion secondary battery. Specifically, examples of negative electrode active materials include soft carbon (easily graphitized carbon), amorphous carbon materials, graphite, hard carbon (difficult-to-graphitize carbon), carbon nanotubes, silicon compounds, etc. Furthermore, these negative electrode active materials can be used individually or in combination of two or more. Additionally, the negative electrode active material layer 42 may also contain various additives such as binders, conductive additives, inorganic fillers, or thickeners.

[0089] <Diaphragm 50a, 50b>

[0090] The separators 50a and 50b in this embodiment are porous sheets with insulating properties. The shape and size of the separators 50a and 50b are not particularly limited, as long as they are appropriately determined according to the design of the energy storage device. Typically, since the separators 50a and 50b insulate the positive electrode 30 from the negative electrode 40, the dimensions of the separators 50a and 50b are larger than those of the positive electrode 30 and the negative electrode 40. The material of the separators 50a and 50b can be any known separator used in such energy storage devices, and is not particularly limited. For example, resins such as polyethylene or polypropylene, polyester, cellulose, or polyamide are preferably used as materials for the separators 50a and 50b.

[0091] <Exterior body 10>

[0092] The outer casing 10 is a metal housing that houses the electrode body 20. In this embodiment, the outer casing 10 has a hexahedral shape (in other words, a square shape) capable of housing the electrode body 20. In this embodiment, the electrode body 20 is housed in the outer casing 10 in a stacked configuration, wherein a strip-shaped positive electrode 30 and a strip-shaped negative electrode 40 are overlapped along a pair of opposing wide surfaces 11a1, 11a2 in the square housing, separated by diaphragms 50a, 50b. The outer casing 10 consists of a housing body 11 and two sealing plates 13a, 13b. Furthermore, in this embodiment, a positive electrode external terminal 14 or a negative electrode external terminal 15 is respectively provided on the two sealing plates 13a, 13b.

[0093] The main body 11 is a so-called cylindrical component. The main body 11 has a pair of opposing wide surfaces 11a1, 11a2 and a pair of opposing narrow surfaces 11b1, 11b2 along the left-right direction X. The pair of opposing narrow surfaces 11b1, 11b2 and the pair of opposing wide surfaces 11a1, 11a2 are continuous along their long sides. The main body 11 has openings 10a, 10b on both sides along the left-right direction X (see reference). Figure 3 Furthermore, in the following description, for convenience, one of the pair of opposing wide surfaces 11a1 and 11a2 will be referred to as the "first surface," and the other wide surface 11a2 will be referred to as the "second surface." Additionally, one of the pair of opposing narrow surfaces 11b1 and 11b2 will be referred to as the "bottom surface," and the other narrow surface 11b2 will be referred to as the "top surface."

[0094] There is no particular limitation on the thickness (plate thickness) of the main body 11 of the shell, i.e., the average plate thickness of the wide sections 11a1 and 11a2 and the narrow sections 11b1 and 11b2. Typically, the upper limit of the thickness (plate thickness) of the main body 11 of the shell can be less than 3 mm, less than 2 mm, or less than 1 mm. The lower limit of the thickness (plate thickness) of the main body 11 of the shell can be more than 0.3 mm, more than 0.4 mm, or more than 0.5 mm.

[0095] In this embodiment, the housing body 11 can be manufactured, for example, by bending a metal sheet into a cylindrical shape and joining the seams (e.g., welding, bonding, etc.). Furthermore, in this embodiment, a welded joint 10c is formed on the upper surface 11b2 along the left-right direction X. Figure 1 (wavy lines).

[0096] Sealing plates 13a and 13b are plate-shaped members that seal a pair of openings 10a and 10b of the housing body 11. In this embodiment, sealing plates 13a and 13b are rectangular members that abut against the side peripheries of the pair of openings 10a and 10b and seal the pair of openings 10a and 10b of the housing body 11. In this embodiment, a positive external terminal 14 is installed on one sealing plate 13a in an insulated state. A negative external terminal 15 is installed on the other sealing plate 13b in an insulated state. Furthermore, in the following description, for convenience, one of the sealing plates 13a and 13b will be referred to as the "first sealing plate" and the other sealing plate 13b as the "second sealing plate".

[0097] With the electrode body 20 housed inside, the outer casing 10 seals a pair of openings 10a and 10b using sealing plates 13a and 13b. In this embodiment, for example, the positive electrode tab 31c of the electrode body 20 is connected to the positive electrode internal terminal 16 (see reference). Figure 3 Additionally, the negative electrode internal terminal 17 is connected to the negative electrode tab 41c of the electrode body 20 (see reference). Figure 3Furthermore, the negative electrode internal terminal 17 is connected to the negative electrode external terminal 15, and a sealing plate 13b is installed on the negative electrode tab 41c of the electrode body 20. In this state, the positive electrode tab 31c side, on which the positive electrode internal terminal 16 is installed, is inserted into the opening 10b of the housing body 11, and the electrode body 20 is inserted into the housing body 11. The positive electrode internal terminal 16, which protrudes from the opening 10a on the other side of the housing body 11, is connected to the positive electrode external terminal 14 installed on the sealing plate 13a. Thus, the positive electrode tab 31c of the electrode body 20 inserted into the housing body 11 is fitted with a sealing plate 13a, and the negative electrode tab 41c is fitted with a sealing plate 13b. Then, the peripheral portions of the sealing plates 13a and 13b are respectively welded to the peripheral portions of the openings 10a and 10b. Thus, the pair of openings 10a and 10b of the housing body 11 are sealed by the sealing plates 13a and 13b.

[0098] In addition, Figures 1-3 The illustrated form shows an outer casing 10 with sealing plates 13a and 13b mounted on both sides of a cylindrical housing body 11 open at both ends. That is, this illustrates a so-called two-terminal type energy storage device with a positive external terminal 14 and a negative external terminal 15 mounted on the sealing plates 13a and 13b on both sides. However, the energy storage device is not limited to this form. For example, the energy storage device could be composed of a box-shaped housing body with a bottomed cuboid shape and an opening on one side (upper surface), and a sealing plate that seals the upper surface of the housing body. That is, both the positive and negative external terminals could be mounted on a single sealing plate.

[0099] From the viewpoint of protecting the electrode body 20 from impact and ensuring the durability of the outer casing 10, the material of the outer casing 10 is preferably a metallic material such as aluminum, aluminum alloy, iron, or iron alloy.

[0100] Alternatively, the outer casing 10 may be provided with a safety valve (not shown) and an injection port (not shown). The safety valve is a thin-walled valve configured to release internal pressure if the internal pressure of the outer casing 10 rises above a predetermined level. The injection port is a hole for injecting electrolyte. Since the injection port is not needed after electrolyte injection, it can be sealed by laser welding. Alternatively, the injection port can also be sealed by installing a plug or the like. Although not shown here, the safety valve may be provided, for example, on the bottom surface 11b1. Furthermore, the injection port may be provided, for example, on either the first sealing plate 13a or the second sealing plate 13b.

[0101] The positive and negative external terminals 14 and 15 for external connection are provided exposed outside the housing 10. These external terminals are electrically connected to the electrode body 20 housed within the housing 10. More specifically, the positive terminal 30 of the electrode body 20 is electrically connected to the positive external terminal 14 exposed from the housing 10. Additionally, the negative terminal 40 of the electrode body 20 is electrically connected to the negative external terminal 15 exposed from the housing 10. Suitable examples of the energy storage device of this disclosure include... Figure 1 and Figure 2 As shown, the external terminals are exposed from both ends of the outer casing 10. The positive external terminal 14 is disposed on either of the pair of sealing plates 13a and 13b. The negative external terminal 15 is disposed on the sealing plate opposite to the sealing plate where the positive external terminal 14 is disposed. This ensures sufficient space for current collectors such as tabs, even on narrower sides. In this embodiment, the positive external terminal 14 is disposed on the first sealing plate 13a. The negative external terminal 15 is disposed on the second sealing plate 13b. Furthermore, both the positive and negative external terminals 14 are made of metal. For example, aluminum or an aluminum-based alloy can be used as the positive external terminal 14. For example, copper or a copper alloy can be used as the negative external terminal 15.

[0102] like Figure 3 As shown, the positive external terminal 14 can be electrically connected to the electrode body 20 via the positive internal terminal 16. Similarly, the negative external terminal 15 can be electrically connected to the electrode body 20 via the negative internal terminal 17. Both the positive internal terminal 16 and the negative internal terminal 17 are made of metal. For the positive internal terminal 16, from the viewpoint of improving the bonding strength with the positive electrode tab 31c (or the non-forming portion 31a of the positive active material layer), aluminum or an aluminum alloy can be used, for example. For the negative internal terminal 17, from the viewpoint of improving the bonding strength with the negative electrode tab 41c (or the non-forming portion 41a of the negative active material layer), copper or a copper alloy can be used, for example.

[0103] Furthermore, the positive external terminal 14 and the negative external terminal 15 are installed on the outside of the sealing plates 13a and 13b in an insulated state via a gasket (not shown). The positive internal terminal 16 and the negative internal terminal 17 are installed on the inside of the sealing plates 13a and 13b via an insulator (not shown). For example, insulating materials with excellent chemical resistance and weather resistance can be used as the gasket and insulator materials.

[0104] <Electrolytes>

[0105] The outer casing 10 houses the electrolyte. For example, the electrolyte can be a liquid electrolyte (electrolyte) that is liquid at room temperature (25°C). Conventionally known non-aqueous electrolytes can be used as this electrolyte without particular limitation. Carbonate-based electrolytes are preferred. Furthermore, in addition to the aforementioned non-aqueous electrolytes, solid electrolytes composed entirely of solids can also be used as the electrolyte.

[0106] Furthermore, in such a closed-type energy storage device, expansion and contraction occur due to charging and discharging, and over time, there is a tendency for internal expansion to cause the outer casing 10 to swell. This tendency for the outer casing 10 to swell becomes stronger as the closed-type energy storage device becomes larger and has higher energy density. The inventors considered suppressing the swelling of the energy storage device. According to the inventors' understanding, in square-shaped energy storage devices, swelling makes it particularly easy for the outer casing 10 to deform or for loads to be applied to the corners of the outer casing.

[0107] Figure 5 This is a schematic diagram used to illustrate the expanded state of an energy storage device. Figure 6 It is an enlarged cross-sectional view used to illustrate the expanded state of energy storage devices. Figure 6 Enlarged to show the Figure 5 A cross-sectional view of the corner 70 formed by the short sides of the narrow surfaces 11b1 and 11b2 and the sealing plates 13a and 13b.

[0108] Energy storage devices gradually expand due to repeated charging and discharging. Reasons for this expansion include, for example, the expansion of the housed electrodes and the generation of gas inside the outer casing. When gas is generated inside the outer casing, the internal pressure increases. Therefore, as... Figure 5 As shown, the sides of the outer casing 10 expand significantly. That is, a force is applied to the sides from inside the outer casing 10, and due to this stress, it is in a state where it is prone to being loaded at the corners. Figure 6 As shown, the outer casing 10 expands as the internal pressure increases. Furthermore, the corner 70 is pulled to both sides by a pair of opposing narrow surfaces 11b1 and 11b2 pressed from the inside of the outer casing 10 and the second sealing plate 13b. This applies a load to the corner 70.

[0109] Furthermore, from the viewpoint of improving volumetric energy efficiency, the energy storage device preferably has a square outer casing 10. As described above, the square energy storage device is hexahedral in shape (i.e., composed of six faces). Since the pressure applied to each face of the square outer casing 10 is not uniform, the larger the area of ​​the face, the more it will expand (especially near the center of the face). Therefore, in the square outer casing 10, the larger the area of ​​the face, the more easily it is affected by the increase in internal pressure of the energy storage device and the more easily it is deformed. As a result, stress tends to concentrate at the corner 70 formed by the short side (in this embodiment, the joint between the housing body 11 and the sealing plates 13a, 13b) and thus apply load.

[0110] Based on this insight, the inventors have proposed a new structure for energy storage devices. Figure 7 This is a schematic top view of the lithium-ion secondary battery 1 viewed from the narrow 11b2 side. Figure 8 This is a schematic top view of the lithium-ion secondary battery 1 as seen from the wide-format 11a1 side. Figure 9 This is an explanatory diagram illustrating a method for winding the fiber 60 of a lithium-ion secondary battery 1. Furthermore, in Figure 9 In order to illustrate the winding method of fiber 60, Figure 6 Simplify and display. Figures 7-9 The lithium-ion secondary battery 1 employs the energy storage device structure proposed herein.

[0111] <Fiber 60>

[0112] like Figure 7 As shown, in this embodiment, fiber 60 is wound around a pair of opposing narrow webs 11b1, 11b2. Additionally, as... Figure 8 As shown, fiber 60 is also wound on a pair of opposing wide surfaces 11a1, 11a2. That is, fiber 60 is continuously wound on a pair of opposing wide surfaces 11a1, 11a2 and a pair of opposing narrow surfaces 11b1, 11b2 via corners 80 formed by the long sides.

[0113] Fiber 60 has: a first fiber 61 wound along a first direction on narrow webs 11b1 and 11b2; and a second fiber 62 wound along a second direction on the narrow webs 11b1 and 11b2. The second direction is oriented in a direction different from the first direction. Specifically, as... Figure 7 As shown, the first fiber 61 and the second fiber 62 are wound in a cross manner around the outer casing 10.

[0114] When viewed from above on the side where the fiber 60 is wound, the angle α at which the first fiber 61 is wound around the outer casing 10 is preferably 10° to 80° (more preferably 20° to 70°, and even more preferably 30° to 60°). Hereinafter, the term "angle" used for the fiber in this specification refers to... Figure 9 The angle shown is the angle between the line that divides the side surface (here, the upper surface 11b2) of the outer casing 10 in two along the central axis AX and the direction of the fiber 60 wound around the outer casing 10. Additionally, angle α is the angle of the first fiber 61 wound around the line that divides the side surface (here, the upper surface 11b2) of the outer casing 10 in two along the central axis AX. Furthermore, the term "central axis" used for the outer casing in this specification refers to a line passing through the center of each of a pair of opposing side surfaces. In this embodiment, the central axis AX is depicted as passing through the center of the surface with the smallest area. More specifically, it is a line passing through the center of the side surface (first sealing plate 13a) where external terminals (specifically, positive external terminal 14 and / or negative external terminal 15) are provided and the center of the surface opposite to that side (second sealing plate 13b). Additionally, angle β is the angle of the second fiber 62 wound around the line that divides the side surface (here, the upper surface 11b2) of the outer casing in two along the central axis AX. The angle β at which the second fiber 62 is wound around the outer body 10 is preferably -80° to -10° (more preferably -70° to -20°, and even more preferably -60° to -30°).

[0115] In addition, such as Figure 9 As shown, the angle between the first direction and the second direction is defined as θ. θ is not particularly limited. From the viewpoint of easily suppressing the expansion of the side of the outer casing 10, the upper limit of the angle θ between the first direction and the second direction can be 160° or less, preferably 140° or less, more preferably 120° or less, and even more preferably 90° or less. Furthermore, the lower limit of θ is preferably 20° or more, more preferably 40° or more, and even more preferably 60° or more.

[0116] The fineness (e.g., diameter) of the fiber 60 is not particularly limited as long as it does not significantly impair the technical effects of this disclosure. Furthermore, the fiber 60 can be formed by overlapping the first fiber 61 and the second fiber 62 to form a layer. In this embodiment, the second fiber 62 is wound around the first fiber 61 wound around the housing body 11 (from the outer side of the housing body 11). The layer of fiber 60 has a thickness. The thickness of the layer (in other words, the thickness when the fiber 60 is wound around the housing body 11) is not particularly limited. From the viewpoint of improving impact resistance, the thickness of the layer relative to the thickness (plate thickness) of the housing body 11 is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. Additionally, the upper limit of the layer thickness relative to the thickness (plate thickness) of the housing body 11 can be 30% or less, or 25% or less, or 22% or less. The thickness of the first fiber 61 can be the same as or different from the thickness of the second fiber 62. Furthermore, the order in which the first fiber 61 and the second fiber 62 are wound is not particularly limited. Alternatively, the first fiber 61 can be wound around the second fiber 62. Furthermore, the first fiber 61 can be wound around the first fiber 61 in a further overlapping manner, and the second fiber 62 can be wound around the second fiber 62 in a further overlapping manner. It is also possible that, after winding the first fiber 61 and the second fiber 62, the first fiber 61 and the second fiber 62 can be wound around in any order.

[0117] The spacing of the fibers 60 (first fiber 61 or second fiber 62) wound in the same direction is not particularly limited, provided that it does not significantly impair the technical effect of this disclosure. In addition, the spacing of the wound fibers 60 in the first fiber 61 and the second fiber 62 can be the same or different.

[0118] Suitable fibers 60 include, for example, glass fiber, carbon fiber, and aramid fiber. Because these fibers have high tensile strength, the strength of the area covered by the fiber can be improved. Glass fiber, among these fibers, has the advantage of excellent thermal insulation. Carbon fiber has the advantage of excellent machinability and ease of processing. Furthermore, aramid fiber has the advantage of excellent insulation. The material of fiber 60 can be appropriately determined according to the purpose.

[0119] Fiber 60 contains a resin as a base material. Suitable resins include, for example, thermosetting resins and thermoplastic resins. Examples of thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenolic resins, polyurethane resins, and silicone resins. Examples of thermoplastic resins include polyolefin resins, polyvinyl chloride resins, polystyrene resins, and fluoropolymers.

[0120] Furthermore, as a suitable manufacturing method for the outer casing 10, it may include a process of winding resin-impregnated fibers 60 onto the outer casing 10 and a process of curing the resin.

[0121] In the process of winding the resin-impregnated fiber 60 onto the outer casing 10, the cylindrical outer casing 10 is prepared before sealing the opening 10b. The mandrel (core) to which the outer casing 10 is fixed is rotated, and the fiber 60 is wound onto the side of the outer casing 10 (here, a pair of opposing wide surfaces 11a1, 11a2 and a pair of opposing narrow surfaces 11b1, 11b2). At this time, by moving the mandrel and / or the spool along the central axis AX while winding the fiber 60 onto the outer casing 10, it is possible to wind at an angle. Furthermore, in the energy storage module 100 described later, since the wide surfaces 11a1, 11a2 of the lithium-ion secondary battery 1 are arranged facing each other, therefore, as... Figure 5 As shown, in this embodiment, the fiber 60 is wound onto a pair of opposing wide surfaces 11a1 and 11a2 (see reference) in a manner orthogonal to the central axis AX. Figure 8 ).

[0122] In the resin curing process, for example, when using a thermosetting resin as the base material, the fibers 60 can be fixed by firing with a heater or the like. According to this manufacturing method, since a fiber-reinforced layer is formed by continuously covering the side of the energy storage device with the fibers 60, the resistance to internal pressure increases can be improved. Furthermore, the above manufacturing method is not limited to the manufacturing method of the energy storage device disclosed herein. As another manufacturing method, the outer casing 10 covered by the fibers 60 can also be manufactured by sheet winding or the like.

[0123] Thus, the outer casing 10 of the energy storage device disclosed herein is covered with a fiber-reinforced resin layer. Therefore, the strength of the outer casing 10 can be improved. Furthermore, the outer casing 10 is protected from swelling by winding the fiber 60. This helps to suppress deformation of the outer casing 10.

[0124] In the above embodiment, continuous fibers 60, covering the outer peripheral side, are wound around the outer casing 10 in a manner arranged along a predetermined direction. Based on these fibers 60, expansion of the sides of the outer casing 10 can be suppressed. As a result, stress can be prevented from being applied to the corners 70 of the outer casing 10.

[0125] In the above embodiment, the energy storage device includes an electrode body 20 and an outer casing 10. The outer casing 10 is a square housing having a pair of opposing wide surfaces 11a1, 11a2 and a continuous pair of opposing narrow surfaces 11b1, 11b. The electrode body 20 has a laminated structure in which a strip-shaped positive electrode 30 and a strip-shaped negative electrode 40 are overlapped along the pair of opposing wide surfaces 11a1, 11a2 in the square housing, separated by a separator 50. According to this structure, the flat surface 21 of the electrode body 20 faces the wide surface (first surface 11a1 or second surface 11a2) of the outer casing 10. Therefore, even when the wide surfaces 11a1, 11a2 are pressed in a way that matches the expansion of the electrode body 20, the outer casing 10 can be pressed in such a way that it does not expand. As a result, the load applied to the corner 80 can be suppressed.

[0126] In the above embodiment, on the side of the outer casing 10, the first fiber 61 is wound along a direction forming an angle α. Additionally, the second fiber 62 is wound along a direction forming an angle β. Thus, on a pair of opposing narrow surfaces 11b1 and 11b2 of the outer casing 10, the first fiber 61 and the second fiber 62 are wound in a crossed manner. This allows for constraint of the side surfaces (wide surfaces 11a1 and 11a2 and narrow surfaces 11b1 and 11b2) of the outer casing 10, and appropriately suppresses swelling caused by an increase in internal pressure of the outer casing 10. Furthermore, in this embodiment, the narrow surfaces (here, the upper surface 11b2) are welded together during the fabrication of the cylindrical shell body 11. Since the first fiber 61 and the second fiber 62 cover the upper surface 11b2 of the outer casing 10 in a crossed manner, the welded joint 10c can be appropriately protected. As a result, the strength of the outer casing 10 can be improved.

[0127] <Energy Storage Module>

[0128] The energy storage module includes the energy storage device and the constraint member of this disclosure, wherein the constraint member arranges multiple energy storage devices in a predetermined direction and constrains them.

[0129] As a suitable example of utilizing the energy storage device disclosed herein, examples can be cited. Figure 9 The energy storage module 100 is shown. Figure 10 This is a perspective view schematically showing an energy storage module including an energy storage device according to another embodiment disclosed herein. The energy storage module 100 includes multiple energy storage devices (e.g., lithium-ion secondary batteries 1) and a restraining member 110.

[0130] like Figure 10As shown, in this example, the wide surfaces 11a1 and 11a2 of the lithium-ion secondary battery 1 are arranged facing each other and along the front-back direction Z to form a laminate 2. Furthermore, the positive electrode external terminals 14 and negative electrode external terminals 15 provided on a pair of sealing plates 13a and 13b are arranged alternately with varying orientations. Here, the positive electrode external terminal 14 of one adjacent lithium-ion secondary battery 1 and the negative electrode external terminal 15 of the other lithium-ion secondary battery 1 can be electrically connected to each other via a metal busbar (not shown). However, the structure of this embodiment does not limit the arrangement or connection method of the lithium-ion secondary batteries 1. The lithium-ion secondary batteries 1 can be connected in series or in parallel.

[0131] Furthermore, the energy storage module disclosed herein can also have multiple spacers. For example... Figure 9 As shown, the energy storage module 100 includes multiple spacers 120. The spacers 120 are disposed between the wide surfaces 11a1 and 11a2 of the lithium-ion secondary battery 1 and the wide surfaces 11a1 and 11a2 of the opposing lithium-ion secondary battery 1. The spacers 120 have the function of suppressing swelling by applying a load to the sides of the lithium-ion secondary battery 1. Furthermore, the spacers 120 also function as buffers to protect the lithium-ion secondary battery 1 from external impacts, vibrations, etc. Moreover, conventionally known spacers can be used as spacers 120. The material of the spacers 120 is not particularly limited. A rubber-based material (thermosetting elastomer) is preferred for the material of the spacers 120.

[0132] <Constraint Components>

[0133] As a preferred example of the constraint member constituting the energy storage module disclosed herein, examples can be listed as follows: Figure 9 The constraint member shown is described. In this example, the constraint member 110 has a pair of opposing end plates 112, a pair of side rods 113, and a base plate 111. The pair of end plates 112 includes: a first end plate 112a, which is disposed at one end (in this case, the end of the front F) of the plurality of lithium-ion secondary batteries 1 arranged thereon; and a second end plate 112b, which is disposed at the other end (in this case, the end of the rear Rr). The pair of side rods 113 connect the first end plate 112a and the second end plate 112b opposite to the first end plate 112a. In this example, the first side rod 113a and the second side rod 113b are each provided in pairs to support a pair of sealing plates 13a, 13b that form the sides of the lithium-ion secondary batteries 1. In addition, the base plate 111 is configured to abut against the bottom surface 11b1 of the plurality of lithium-ion secondary batteries 1. The upper surface 11b2 of multiple lithium-ion secondary batteries 1 is in a state where it is not supported by the constraint member 110.

[0134] In the aforementioned energy storage module, a pair of opposing wide surfaces 11a1 and 11a2 of the lithium-ion secondary battery 1 are constrained. That is, when a load is applied in the stacking direction of the lithium-ion secondary battery 1 (here, the front-to-back direction Z), the expansion of the pair of opposing wide surfaces 11a1 and 11a2 is suppressed. Therefore, in such a constrained energy storage device (i.e., energy storage module), the pressure is further concentrated on a pair of opposing narrow surfaces 11b1 and 11b2, making expansion easier. In contrast, the pair of opposing narrow surfaces 11b1 and 11b2 of the lithium-ion secondary battery 1 are covered by fiber 60. As a result, the expansion of the outer casing 10 is suppressed, thus reducing the load on the diagonal portion 70.

[0135] In addition, as other preferred examples of the energy storage module disclosed herein, examples can be listed. Figure 11 A battery pack-type energy storage module as shown. Figure 11 This is a schematic perspective view of the battery pack housing type energy storage module 102 disclosed herein. Figure 11 In order to understand the structure of the battery pack housing type energy storage module 102, a portion of it is disassembled and shown. The battery pack housing type energy storage module 102 is a cell-to-pack structure that houses multiple lithium-ion secondary batteries 1 inside a restraining member 110 (in this example, a battery pack housing 210).

[0136] The battery pack housing 210 used in the battery pack housing type energy storage module 102 disclosed herein has a bottom wall 211, a side wall 212, and a top wall (not shown). Figure 11 As shown, the sidewall 212 extending along the left-right direction X directly supports both ends of the laminate 2. Multiple lithium-ion secondary batteries 1 are disposed on the bottom wall 212. The lithium-ion secondary batteries 1 and the bottom wall 211 can be bonded together using an adhesive or the like. Thus, the lithium-ion secondary batteries 1 are fixed within the battery pack housing 210. The upper wall forms the upper part of the battery pack housing 210. The upper wall faces the bottom wall 211. The upper wall is configured to cover the multiple lithium-ion secondary batteries 1 housed within the battery pack housing 210.

[0137] In this cell-to-pack configuration, the sidewalls 212 of the battery pack housing 210 directly support both ends of the stacked lithium-ion secondary battery 1. According to this structure, since the number of constraining components can be reduced, the volumetric energy efficiency of the module can be improved.

[0138] In the aforementioned Cell-to-Pack configuration, a pair of opposing wide surfaces 11a1 and 11a2 of the lithium-ion secondary battery 1 are constrained. Therefore, the expansion of the constrained wide surfaces 11a1 and 11a2 is suppressed. However, pressure is further concentrated on the unconstrained pair of opposing narrow surfaces 11b1 and 11b2, making expansion easier. Furthermore, unlike the aforementioned energy storage module 102, since the number of constraining members 110 is smaller, it is preferable to increase the strength of the energy storage device and protect it from impacts, vibrations, etc. Here, the lithium-ion secondary battery 1 is covered by fiber 60. As a result, since the expansion of the outer casing 10 is suppressed, the load on the diagonal portion 70 can be reduced. Additionally, the strength of the outer casing 10 can be increased, making it more resistant to impacts and vibrations.

[0139] The above details specific examples of the technology disclosed herein, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes solutions obtained by various modifications and alterations to the specific examples illustrated above.

[0140] Provided that no particular problems arise, the technology disclosed herein allows for the appropriate omission or combination of the constituent elements and processes mentioned herein. Furthermore, this specification includes disclosures described in the following items.

[0141] Project 1: An energy storage device, wherein the energy storage device comprises: an electrode body having a positive electrode and a negative electrode; and a metal outer casing housing the electrode body, wherein continuous fibers are wound around the outer casing in a manner that covers the outer peripheral side and are arranged in a predetermined direction.

[0142] Project 2: According to the energy storage device of Project 1, wherein the outer casing is a square housing having a pair of opposing wide surfaces and a pair of opposing narrow surfaces continuous with the wide surfaces, the electrode body has a laminated structure in which sheet-like positive electrodes and sheet-like negative electrodes are overlapped along the pair of opposing wide surfaces in the square housing through a separator, and the fiber is continuously wound around the pair of opposing wide surfaces and the pair of opposing narrow surfaces.

[0143] Project 3: An energy storage module, wherein the energy storage module comprises: the energy storage device described in Project 1 or 2; and a constraint member, the constraint member arranging and constraining multiple energy storage devices in a predetermined direction.

Claims

1. An energy storage device, wherein, The energy storage device includes: An electrode body having a positive electrode and a negative electrode; and A metal casing, which houses the electrode body. Continuous fibers, arranged in a predetermined direction, are wound around the outer casing to cover the outer periphery.

2. The energy storage device according to claim 1, wherein, The outer casing is a square shell having a pair of opposing wide faces and a pair of opposing narrow faces continuous with the wide faces. The electrode body has a stacked structure in which a strip-shaped positive electrode and a strip-shaped negative electrode overlap with a diaphragm along a pair of opposing wide surfaces in the square housing. The fibers are continuously wound around the pair of opposing wide surfaces and the pair of opposing narrow surfaces.

3. An energy storage module, wherein, The energy storage module has the following features: The energy storage device according to claim 1 or 2; and A constraint member is provided, which arranges and constrains multiple energy storage devices in a predetermined direction.

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