Power storage module

Abstract

The invention provides a power storage module capable of suppressing a bound load from becoming too high due to expansion of a power storage device. A power storage module (100) is provided with a plurality of power storage devices, a constraining member (110), and a spacer (120). The plurality of power storage devices have a pair of wide surfaces (11b1, 11b2) facing each other, and the wide surfaces (11b1, 11b2) are arranged so as to face each other. The binding member (110) is configured so as to bind the plurality of power storage devices in a direction in which the wide surfaces (11b1, 11b2) of the plurality of power storage devices are arranged so as to face each other. The spacer (120) is disposed between the power storage device disposed at a first end portion (2a) in a direction in which the plurality of devices are arranged and the constraining member (110), and the thickness of the spacer (120) becomes smaller when a load greater than a predetermined load is applied in the direction in which the power storage devices are arranged.

Description

Technical Field

[0001] This disclosure relates to energy storage modules. Background Technology

[0002] It is known that secondary batteries, such as lithium-ion batteries, will expand after prolonged use if repeatedly charged and discharged. Japanese Patent Application Publication No. 2022-13634 discloses a battery pack technology. The battery pack disclosed in this publication includes: multiple battery cells; multiple plate-shaped spacers; and insulating members disposed between the spacers, different from the spacers. The multiple battery cells have a rectangular shape and are bound together in a predetermined arrangement direction. Between the battery cells, two plate-shaped spacers are arranged facing each other. The insulating members have a higher rigidity than the spacers and are provided in such a way that they contact the two spacers sandwiching the insulating members at multiple locations between the spacers disposed between the battery cells. It is described that the insulating member has a thickness that does not penetrate the arrangement direction of the spacers even when the distance between the two spacers becomes minimal due to the increase in binding load. As a result, in addition to the expansion of the battery cells due to charging and discharging, the battery cells also expand due to long-term use and aging, which increases the binding load. In this case, by embedding an insulating member with a higher hardness than the spacers into the spacers, the increase in binding load beyond the expected limit can be suppressed.

[0003] Japanese Patent Application Publication No. 2022-77843 discloses a battery module having a laminated structure, which is formed by laminating multiple battery cells having negative electrodes containing lithium metal or lithium metal. The battery module has a fixing member at the center in the lamination direction. This fixing member fixes the battery cells located on both sides of the fixing member in the lamination direction.

[0004] Japanese Patent Application Publication No. 2023-116166 discloses a plurality of battery cells arranged in a first direction. Electrode terminals (positive and negative terminals) are formed on a frame housing these battery cells, arranged in a second direction orthogonal to the first direction. In such a battery module, the side portion of the frame can directly support the laminate of the battery cells.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-13634

[0008] Patent Document 2: Japanese Patent Application Publication No. 2022-77843

[0009] Patent Document 3: Japanese Patent Application Publication No. 2023-116166 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, the inventors of this application considered to improve the situation where the binding load of the energy storage module becomes too high due to the expansion of the energy storage device.

[0012] Solution for solving the problem

[0013] The energy storage module disclosed herein includes multiple energy storage devices, a binding member, and a spacer. The multiple energy storage devices have a pair of opposing wide surfaces, which are arranged facing each other. The binding member is configured to bind the multiple energy storage devices in the direction in which the wide surfaces are arranged facing each other. The spacer is disposed between the energy storage device located at the first end of the arrangement direction and the binding member. Furthermore, when a load greater than a predetermined load is applied along the arrangement direction, the thickness of the spacer decreases.

[0014] This energy storage module improves the situation where the binding load on the energy storage module becomes too high due to the expansion of the energy storage device. Attached Figure Description

[0015] Figure 1 This is a schematic 3D view of the energy storage module.

[0016] Figure 2 This is a schematic side view of the energy storage module.

[0017] Figure 3 This is a schematic 3D view of a lithium-ion battery.

[0018] Figure 4 This is a schematic longitudinal sectional view of a lithium-ion battery.

[0019] Figure 5 This is a schematic exploded view of the electrode.

[0020] Figure 6 This is a schematic plan view illustrating a preferred embodiment (fractured spacer) of the spacer disclosed herein.

[0021] Figure 7 This is a longitudinal sectional view schematically showing the state of the spacer disclosed herein in a preferred manner (fractured spacer) before operation.

[0022] Figure 8 This is a longitudinal sectional view schematically showing the state of the spacer after operation in a preferred manner (fractured spacer) of the spacer disclosed herein.

[0023] Figure 9 This is a plan view schematically illustrating a preferred embodiment of the spacer disclosed herein (a convex-side spacer in a fitting manner).

[0024] Figure 10 This is a plan view schematically illustrating a preferred embodiment of the spacer disclosed herein (a recessed-side spacer in a fitting manner).

[0025] Figure 11 This is a longitudinal sectional view schematically showing the state of the spacer disclosed herein in a preferred manner (fitting spacer) before operation.

[0026] Figure 12 This is a longitudinal sectional view schematically showing the state of the spacer disclosed herein after operation (fitting spacer).

[0027] Figure 13 This is a schematic side view of an energy storage module involved in other embodiments disclosed herein.

[0028] Figure 14 This is an explanatory diagram illustrating the operation of the spacer of the energy storage module according to other embodiments disclosed herein.

[0029] Figure 15 This is a schematic perspective view of the encased energy storage module disclosed herein. Detailed Implementation

[0030] The energy storage module of this disclosure will now be described. Furthermore, in the following figures, components and parts that perform the same function will be labeled with the same reference numerals. Also, the dimensional relationships (length, width, thickness, etc.) in the figures do not reflect actual dimensional relationships. In the following description, reference numerals L, R, U, and D in the figures denote the left, right, top, and bottom of the energy storage module and the lithium-ion secondary battery 1 described later. Furthermore, the vertical direction (height direction Y), horizontal direction (width direction X), and front-back direction (column direction Z) are specified. However, these are merely for ease of explanation and do not limit the arrangement of the energy storage module.

[0031] <Definitions of Terms>

[0032] In this specification, "energy storage device" is a concept encompassing a device that generates a charging and discharging reaction by moving charge carriers between a pair of electrodes (positive and negative electrodes). That is, an energy storage device may include batteries such as secondary batteries (e.g., lithium-ion secondary batteries, nickel-metal hydride batteries, nickel-cadmium batteries), capacitors such as lithium-ion capacitors, and double-layer capacitors (physical batteries). Furthermore, the following description uses a typical energy storage device, namely a lithium-ion secondary battery, as an example to illustrate this embodiment. Additionally, in this specification, "lithium-ion secondary battery" refers to an energy storage device that utilizes lithium ions as charge carriers and achieves repeated charging and discharging through the movement of charge accompanying lithium ions between the positive and negative electrodes.

[0033] In this specification, "energy storage module" refers to an assembly of multiple energy storage devices. Additionally, in this specification, "cell" or "battery unit" refers to the individual energy storage devices that can be electrically connected to each other to form an energy storage module.

[0034] 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 the meanings of "greater than A and less than B," "greater than A and less than B," and "above A and less than B."

[0035] <Energy Storage Module 100>

[0036] Figure 1 This is a schematic perspective view of the energy storage module 100. Figure 2 This is a schematic side view of the energy storage module 100. Figure 2 Viewed from other directions (left side (L direction)). Figure 1 The image.

[0037] like Figure 1 As shown, the energy storage module 100 includes multiple energy storage devices, spacers 120, and restraining members 110. Figure 1 In the example shown, the energy storage device is a lithium-ion secondary battery 1, which will be referred to as lithium-ion secondary battery 1 below.

[0038] <Multiple energy storage devices (lithium-ion secondary battery 1)>

[0039] In this embodiment, such as Figure 1 as well as Figure 2 As shown, multiple lithium-ion secondary batteries 1 are arranged in a predetermined direction (column direction Z in this embodiment). Figure 1 In the diagram, the side closest to the center in the Z-direction is designated as the front (reference numeral F), and the side furthest in the direction of depth is designated as the rear (reference numeral Rr). Adjacent lithium-ion secondary batteries 1 have their wide surfaces 11b1 and 11b2 facing each other. That is, multiple lithium-ion secondary batteries 1 are arranged such that their wide surfaces 11b1 and 11b2 face each other. Thus, the multiple lithium-ion secondary batteries 1 are arranged with their positive electrode external terminals 14 and negative electrode external terminals 15 alternating, resulting in an alternating orientation. Furthermore, the positive electrode external terminal 14 of one adjacent lithium-ion secondary battery 1 and the negative electrode external terminal 15 of another adjacent lithium-ion secondary battery 1 can be electrically connected to each other via a metal busbar (not shown). However, the arrangement and connection method of the lithium-ion secondary batteries 1 are not limited. The lithium-ion secondary batteries 1 can be connected in series or in parallel.

[0040] <Energy Storage Device: Lithium-ion Secondary Battery 1>

[0041] Figure 3 This is a schematic three-dimensional view of a lithium-ion secondary battery 1. Figure 4 This is a schematic longitudinal sectional view of a lithium-ion secondary battery 1. Figure 4 It is along Figure 3 A schematic longitudinal sectional view of the lithium-ion secondary battery 1 with IV-IV lines. Additionally, in Figure 4 In order to understand the structure of the electrode body 20, a portion of the electrode body 20 will be shown.

[0042] <Shell 10>

[0043] like Figure 3 As shown, in this embodiment, the housing 10 is rectangular in shape, specifically a flat square. The housing 10 includes a main body 11 that houses the electrode body 20 and electrolyte (not shown); and a sealing plate 12 (cover) that closes the opening of the main body 11. The main body 11 and the sealing plate 12 are sealed (airtight) by welding, such as laser welding. The material of the housing 10 is not particularly limited, as long as it is the same as that used in conventional energy storage devices. For example, the housing 10 can be made of a lightweight metal material with good thermal conductivity, such as aluminum. However, the configuration of the housing 10 can also be changed. For example, a flexible laminated film can be used as the housing.

[0044] In this embodiment, the main body 11 of the housing 10 is composed of a rectangular and elongated bottom surface 11a, a pair of wide surfaces 11b1 and 11b2 extending from the bottom surface 11a and facing each other, and a pair of narrow surfaces 11c1 and 11c2. Furthermore, in the following description, for convenience, one of the pair of facing wide surfaces 11b1 and 11b2 will be referred to as the "first surface," and the other wide surface 11b2 will be referred to as the "second surface."

[0045] Additionally, the housing 10 is provided with a safety valve 13 and an injection port (not shown). The safety valve 13 is a thin-walled valve configured to release the internal pressure when the internal pressure of the housing 10 rises above a specified level. The injection port is a hole for injecting electrolyte. Since the injection port is no longer needed after the electrolyte is injected, it can be closed by laser welding or the like. Alternatively, the injection port can also be closed by a mounting plug.

[0046] The positive external terminal 14 and the negative external terminal 15 for external connection are provided exposed to the outside of the housing 10. These external terminals are electrically connected to the electrode body 20 housed within the housing 10 via the positive internal terminal 16 or the negative internal terminal 17. The positive external terminal 14 and the negative external terminal 15 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.

[0047] The positive electrode internal terminal 16 and the negative electrode internal terminal 17 are made of metal. For the positive electrode 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 electrode active material layer), aluminum or an aluminum alloy can be used, for example. For the negative electrode 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 electrode active material layer), copper or a copper alloy can be used, for example.

[0048] In this embodiment, the positive external terminal 14 and the negative external terminal 15 are mounted on the sealing plate 12 via a gasket 18. Additionally, the positive internal terminal 16 and the negative internal terminal 17 are mounted on the back (inner side) of the sealing plate 12 via an insulator 19. The gasket 18 and the insulator 19 can be made of insulating materials with excellent chemical resistance or weather resistance.

[0049] Electrolyte

[0050] The casing 10 contains the electrolyte. For example, the electrolyte is a liquid electrolyte that is liquid at room temperature (25°C). There are no particular limitations on the electrolyte, and conventionally known non-aqueous electrolytes can be used. Carbonate electrolytes are preferred for non-aqueous electrolytes.

[0051] <Electrode 20>

[0052] The housing 10 houses the electrode body 20. The electrode body 20 has a positive electrode 30 and a negative electrode 40. Figure 5 This is a schematic exploded view of the electrode body 20. In this embodiment, the electrode body 20 is a wound electrode body, in which a strip-shaped positive electrode 30 and a strip-shaped negative electrode 40 are overlapped along the length direction with strip-shaped separators 50a and 50b, and wound around a winding axis WL set in 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, along the winding axis WL, a positive electrode tab 31c is provided at one end of the electrode body 20, and a negative electrode tab 41c is provided at the other end. In addition, the electrode body 20 is not limited to a wound electrode body, and can also be a laminated electrode body in which positive and negative electrodes are alternately laminated with separators. In addition, in the laminated electrode body, it can also be a so-called multi-fold shape in which the strip-shaped separator sandwiches the positive and negative electrodes on one side and is bent in a serrated shape.

[0053] <Positive Electrode 30>

[0054] like Figure 5As shown, the positive electrode 30 includes 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 can reversibly adsorb and release 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 adsorb charge carriers during discharging. In addition, 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 have a non-formed portion 31a of the positive electrode active material layer 32, which exposes the positive electrode current collector foil 31. 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 on the positive electrode current collector foil 31 (more specifically, the non-formed portion 31a) at the edge of the positive electrode active material layer 32. The positive electrode protective layer 31b is a layer that protects the non-forming portion 31a of the positive electrode active material layer, and may be a layer containing inorganic fillers (such as alumina).

[0055] 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, without particular limitation. For example, the material of the positive electrode current collector foil 31 is aluminum or an aluminum alloy. As the positive electrode active material layer 32, the positive electrode active material used in the positive electrode of a typical lithium-ion secondary battery 1 can be used. Examples of lithium composite metal oxides include LiCoO2, LiNiO2, LiFeO2, and LiNiO2. x Co y Mn 1-x-y O2 (NCM), LiNi 0.5 Mn 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.

[0056] <Negative Electrode 40>

[0057] like Figure 5As shown, the negative electrode 40 includes 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 can reversibly adsorb and release 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 during charging and release charge carriers during discharging. In addition, the negative electrode active material layer 42 can be formed on one side 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 42, which exposes the negative electrode current collector foil 41. The non-formed portion 41a of the negative electrode active material layer is provided at one end of the electrode body 20.

[0058] The material of the negative electrode current collector foil 41 can be any known negative electrode current collector foil used in this type of energy storage device, without particular limitation. For example, the material of the negative electrode current collector foil 41 can be copper or a copper alloy. As the negative electrode active material of the negative electrode active material layer 42, the negative electrode active material used in the negative electrode of a typical lithium-ion secondary battery can be used. Specifically, examples of negative electrode active materials include soft carbon (easily graphitized carbon), amorphous carbon materials, graphite (black lead), 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.

[0059] <Diaphragm 50a, 50b>

[0060] The diaphragms 50a and 50b involved in this embodiment are porous sheets with insulating properties. However, the shape and size of the diaphragms 50a and 50b can be appropriately determined according to the design of the energy storage device, and are not particularly limited. Typically, since the diaphragms 50a and 50b are to insulate the positive electrode 30 and the negative electrode 40, the dimensions of the diaphragms 50a and 50b are larger than those of the positive electrode 30 and the negative electrode 40. The material of the diaphragms 50a and 50b can be any commercially available diaphragms used in such energy storage devices, and is not particularly limited. For example, for the material of the diaphragms 50a and 50b, suitable materials can be polyolefins such as polyethylene or polypropylene, polyesters, cellulose, or polyamide resins.

[0061] <Restraint Component 110>

[0062] like Figure 1 as well as Figure 2As shown, the binding member 110 is a member that binds the plurality of lithium-ion secondary batteries 1 (energy storage devices) and the spacer 120. The binding member 110 is configured to bind the plurality of lithium-ion secondary batteries 1 in a direction (in this embodiment, the column direction Z) in which the wide surfaces 11b1 and 11b2 are arranged facing each other. In this embodiment, as... Figure 1 as well as Figure 2 As shown, the binding member 110 will have a pair of end plates (a first end plate 112a and a second end plate 112b). The end plates are disposed at the start and end points of the direction in which the multiple lithium-ion secondary batteries 1 are arranged with their wide surfaces 11b1 and 11b2 facing each other. More specifically, the binding member 110 has a first end plate 112a disposed on one end of the arranged lithium-ion secondary batteries 1 (i.e., the first end 2a of the laminate 2, which in this embodiment is the lithium-ion secondary battery 1a on the front F side). In addition, the binding member 110 has a second end plate 112b disposed on the other end of the arranged lithium-ion secondary batteries 1 (i.e., the second end 2z of the laminate 2, which in this embodiment is the lithium-ion secondary battery 1z on the rear Rr side). In addition, in this specification, the term "laminate" used to refer to an energy storage device is used to refer to an assembly of cells in which multiple cells are arranged in one direction.

[0063] The restraint member 110 also includes side strips 113 and a base plate 111. In this embodiment, as... Figure 1 As shown, the side strip 113 is mounted between the first end plate 112a and the second end plate 112b. In this binding member 110, a pair of end plates (the first end plate 112a and the second end plate 112b) are connected by the side strip 113 and a plurality of screws 114. However, the first end plate 112a, the second end plate 112b, and the side strip 113 can also be connected by adhesive or welding. In order to arrange the lithium-ion secondary batteries 1 along the column direction Z, the side strip 113 supports the narrow surfaces 11c1 and 11c2 of the lithium-ion secondary batteries 1. In addition, the base plate 111 is disposed in contact with the bottom surface 11a of the plurality of lithium-ion secondary batteries 1.

[0064] The materials of the first end plate 112a and the second end plate 112b, the side strip 113, and the bottom plate 111 are not particularly limited. These materials can be selected from metals or resins, etc. Furthermore, the materials of each component can be the same or different. From the viewpoint of the strength of the binding member 110 or the application of appropriate load to the lithium-ion secondary battery 1 and the spacer 120, these materials are preferably metals. Additionally, the shapes of the first end plate 112a and the second end plate 112b, the side strip 113, and the bottom plate 111 are not particularly limited. For example, the side strip 113 can also be plate-shaped. In this embodiment, the first end plate 112a and the second end plate 112b, and the bottom plate 111 are rectangular and have a predetermined thickness (e.g., a thickness sufficient to drive in multiple screws 114).

[0065] Furthermore, in this embodiment, the binding member 110, the spacer 120, and the laminate 2 are bound in the direction (in this case, the column direction Z) in which the wide surfaces 11b1 and 11b2 of the plurality of lithium-ion secondary batteries 1 are arranged facing each other. Thus, the binding member 110 is configured to apply a predetermined load to the spacer 120 and the lithium-ion secondary batteries 1 along the column direction Z. Furthermore, the binding load of the binding member 110 is not particularly limited as long as it does not significantly impair the technical effects of this disclosure. Energy storage devices such as lithium-ion secondary batteries, for example, expand in volume over long-term use due to repeated charging and discharging. In the initial state of the energy storage device (before expansion), if the binding load is too high, the increase in load due to the expansion of the energy storage device becomes significant, and therefore, the electrolyte is easily squeezed out from the electrode body. From this viewpoint, the upper limit of the initial binding load is preferably 10 kN or less, more preferably 8 kN or less, and even more preferably 6 kN or less. Furthermore, if the initial binding load is too low, the durability of the module decreases (typically, it becomes weaker against external forces such as impacts or vibrations). Furthermore, as the distance between the electrodes increases, the resistance value increases. Therefore, the lower limit of the initial binding load is preferably 4 kN or more, more preferably 4.7 kN or more, and even more preferably 5 kN or more.

[0066] However, the aforementioned sealed energy storage devices expand and contract due to charging and discharging, and their internal structure expands over long-term use, leading to a tendency for the casing 10 to expand. Furthermore, this tendency intensifies when the sealed energy storage device is large and has a high energy density. Therefore, in energy storage modules equipped with such devices, there is a tendency for the binding pressure to gradually increase. Consequently, the sides of multiple energy storage devices (more specifically, the flat surfaces 21 of the electrode bodies 20 within the energy storage device) are subjected to intense compression. Furthermore, the electrolyte contained in the electrode bodies 20 within the energy storage device is forced out between the electrodes. This results in uneven distribution of the electrolyte within the energy storage device (typically, uneven distribution of the concentration of charge carriers (e.g., lithium ions)).

[0067] Based on this insight, the inventors of this application have proposed a novel configuration for the energy storage module. The energy storage module 100 disclosed herein includes a spacer 120. Furthermore, the spacer 120 is disposed between an energy storage device and a restraining member 110 at a first end 2a located in a direction in which the wide surfaces 11b1, 11b2 of the plurality of energy storage devices are arranged facing each other. The thickness of the spacer 120 decreases when a load greater than a predetermined load is applied along the direction in which the wide surfaces 11b1, 11b2 of the plurality of lithium-ion secondary batteries 1 are arranged facing each other.

[0068] <Spacer 120>

[0069] The spacer 120 is disposed abutting against the lithium-ion secondary battery 1. In this embodiment, the spacer 120 is disposed between the lithium-ion secondary battery 1a and the first end plate 112a on the first end 2a side. However, the placement of the spacer 120 is not limited to this. The spacer 120 may also be disposed between the lithium-ion secondary battery 1z and the second end plate 112b on the second end 2z side. Alternatively, the spacer 120 may be disposed between the lithium-ion secondary batteries 1.

[0070] Furthermore, in the case where multiple cells are arranged in one direction, such as in the energy storage module 100, load concentration is likely to occur at the ends of the cell arrangement direction (here, the first end 2a and / or the second end 2z). This is because the increased thickness due to the expansion of each cell is biased towards a certain end. In addition, sometimes not all cells expand uniformly, and the degree of expansion (the thickness after expansion) varies depending on the cell. Even in this case, by providing spacers 120 at the ends, the spacers 120 can absorb the expansion of multiple cells. Therefore, it is preferable that the spacers 120 are disposed at a certain end of the multiple lithium-ion secondary batteries 1 arranged (in other words, the first end 2a and / or the second end 2z of the laminate 2). Moreover, the end-positioning is easier to operate than the spacers being disposed between the cells. In this embodiment, as a preferred example of the spacer 120 configuration, it is disposed between the lithium-ion secondary battery 1a on the first end 2a side and the first end plate 112a. With this configuration, it is easy to limit the orientation of the load to one direction (here, the first end 2a side). Therefore, the spacer 120 can easily absorb the expansion of multiple lithium-ion secondary batteries 1, making it easier to set the operating pressure. Consequently, the dimensional displacement of the spacer 120 can be stabilized.

[0071] The material of the spacer 120 disclosed herein is not particularly limited, as long as it is any material conventionally used in such spacers (e.g., cell spacers). Typically, the material of the spacer 120 can be metal or resin. Examples of metals include aluminum or aluminum-based alloys. Examples of resins include polyolefin resins, polyethylene resins, and ethylene propylene rubber. From the viewpoint of appropriately obtaining the technical effects of this disclosure, the material of the spacer 120 is preferably metal, and particularly preferably aluminum or aluminum-based alloys. Furthermore, from the viewpoint of safety, the spacer 120 is preferably insulating. The aforementioned insulating resin materials can also be used, and for metal materials, an insulating coating is preferred.

[0072] The spacer 120 is a rectangular plate-shaped member. In this embodiment, the spacer 120 is disposed facing the first surface 11b1 of the lithium-ion secondary battery 1a at the first end 2a side. The thickness of the spacer 120 is not particularly limited as long as it achieves the technical effects of this disclosure. However, if the thickness of the spacer 120 is too large, the volumetric energy efficiency of the energy storage module 100 will decrease. Therefore, in the state before binding (before applying a load), when the average thickness of each lithium-ion secondary battery 1 included in the energy storage module 100 is set to 100%, the upper limit of the thickness of the spacer 120 is preferably 5% or less, more preferably 4.5% or less, and even more preferably 4% or less. In addition, if the thickness of the spacer 120 is too small, when the thickness decreases due to the application of a load larger than the predetermined load, the reduction in binding pressure will be smaller. Therefore, the lower limit of the thickness of the spacer 120 is preferably 1% or more, more preferably 1.2% or more, and even more preferably 1.5% or more.

[0073] The spacer 120 disclosed herein has dimensional displacement in the direction (in this case, the column direction Z) in which the wide surfaces 11b1 and 11b2 of the multiple energy storage devices are arranged facing each other. More specifically, it is configured such that its thickness decreases when a load greater than a predetermined load is applied along the column direction Z. The predetermined load is not particularly limited as long as it achieves the technical effect of this disclosure. The predetermined load can be appropriately set according to the purpose (e.g., the application of the energy storage module). Due to the increased load applied in the column direction Z, there is a tendency for electrolyte to be squeezed out from the electrode body 20. From this point of view, the upper limit of the predetermined load is preferably, for example, 90 kN or less, more preferably 85 kN or less, and even more preferably 80 kN or less. In addition, the lower limit is preferably, for example, 10 kN or more, more preferably 50 kN or more, and even more preferably 70 kN or more. Furthermore, the predetermined load is, for example, permissible due to some deviations caused by human or mechanical errors (e.g., ±10%, ±5%, and ±1%, etc.). That is, regarding the term "predetermined load" used in this specification, the numerical values ​​set as described above can be interpreted as being modified by terms such as "substantially," "approximately," and "roughly."

[0074] In the above embodiment, the energy storage module 100 includes a plurality of lithium-ion secondary batteries 1, a spacer 120, and a binding member 110. The spacer 120 is disposed at a first end 2a in a direction in which the plurality of energy storage devices are arranged with their wide surfaces 11b1 and 11b2 facing each other. Furthermore, the spacer 120 is disposed between the lithium-ion secondary batteries 1 and the binding member 110. When a load greater than a predetermined load is applied along the direction in which the plurality of energy storage devices are arranged with their wide surfaces 11b1 and 11b2 facing each other, the thickness of the spacer 120 decreases. According to this spacer 120, when the binding pressure of the energy storage module increases and reaches a predetermined load, the binding can be released, and the binding pressure can be appropriately reduced. Therefore, since the binding pressure of the energy storage module 100 is not too high, the amount of electrolyte squeezed out from the electrode body 20 can be reduced. This suppresses liquid inhomogeneity of the electrolyte within the energy storage device (typically, uneven distribution of the concentration of charge carriers (e.g., lithium ions)). As a result, the deposition of metals (e.g., lithium metal) that act as charge carriers inside the electrode body can be suppressed, and the performance of the energy storage device (e.g., cycle capacity retention rate) can be prevented from deteriorating. In addition, the energy storage module 100 of this disclosure has a high volumetric energy density as a module because it has a small number of components.

[0075] In the above embodiment, the lithium-ion secondary battery 1 has an electrode body 20 and a square housing 10. The binding member 110 has: a first end plate 112a disposed on the side of a first end 2a in a direction in which the wide surfaces 11b1, 11b2 of the plurality of energy storage devices are arranged facing each other; and a second end plate 112b disposed on the side of a second end 2z opposite to the side of the first end 2a. In addition, the binding member 110 has a side strip 113 spanned between the first end plate 112a and the second end plate 112b. As a result, the lithium-ion secondary battery 1 can be easily arranged along the column direction Z. As a result, the dimensional displacement of the spacer 120 of this disclosure can be appropriately utilized. Furthermore, the lithium-ion secondary battery 1 can be easily protected from external impacts or vibrations from the energy storage module 100.

[0076] Furthermore, the thickness of the spacer 120 after the thickness is reduced (i.e., after dimensional displacement) is not particularly limited as long as the technical effects of this disclosure can be achieved. However, from the viewpoint of appropriately obtaining this effect, the spacer 120 is preferably formed such that its thickness is reduced according to the number of battery cells (here, lithium-ion secondary battery 1). Preferably, the thickness of the spacer 120 is reduced by approximately [(number of battery cells arranged in the predetermined direction) × 0.5 to 2.0] mm when a predetermined load is reached. Furthermore, it is more preferable that the thickness of the spacer 120 is reduced by approximately [(number of battery cells arranged in the predetermined direction) × 0.5 to 1.5] mm, and even more preferably by approximately [(number of battery cells arranged in the predetermined direction) × 0.5 to 1.0] mm. This effectively releases the binding pressure.

[0077] <Preferred Examples of Spacers>

[0078] A preferred embodiment of the spacer 120 described above will be described in more detail below. Furthermore, as described above, according to this disclosure, a spacer 120 used in an energy storage module can be provided, which is disposed between the binding member 110 and / or between energy storage devices, and whose thickness decreases when a load greater than a predetermined load is applied along a predetermined direction. Here, the predetermined direction is the same as the direction in which the plurality of lithium-ion secondary batteries 1 are arranged with their wide surfaces 11b1, 11b2 facing each other.

[0079] (Example 1: Fractured spacer 220)

[0080] As a preferred example of the spacer 120 described above, examples include: Figures 6-8 The structure shown is as described. Figure 6 This is a plan view schematically showing a preferred embodiment (fractured spacer 220) of the spacer 120 disclosed herein. Figure 7 This is a longitudinal sectional view schematically showing the state of the spacer 120 disclosed herein before operation (fractured spacer 220). Figure 8 This is a longitudinal sectional view schematically showing the state after operation of a preferred embodiment (fractured spacer 220) of the spacer 120 disclosed herein. In this example, the fractured spacer 220 has a first surface 221a (the surface side) and a second surface 221b, which is the back surface of the first surface 221a. Figure 6 This is a plan view of the fractured spacer 220 viewed from the first side 221a. Figure 7 as well as Figure 8 The view of the bound lithium-ion secondary battery 1a and the fractured spacer 220 is from a direction orthogonal to the column direction Z (in this case, the width direction X). Figure 8 It shows the Figure 7 The fracture spacer 220 is a fracture spacer 220 in which the thickness decreases when a load greater than a predetermined load is applied along the column direction Z.

[0081] like Figure 6 As shown, the fracture spacer 220 includes a protrusion 230, an outer edge 231, and a joint 232. The protrusion 230 is oriented towards... Figure 6 The area protruding from the outer edge 231 near the front side. Furthermore, here, the protrusion 230 is the area protruding from the outer edge 231 in the column direction Z towards the opposing first end plate 112a. For example... Figure 7As shown, in this embodiment, the protrusion 230 abuts against the first end plate 112a by being secured by the binding member 110. Furthermore, the outer edge 231 is the region surrounding the protrusion 230. The outer edge 231 abuts against the wide surface 11b1 of the lithium-ion secondary battery 1a by being secured by the binding member 110. However, the orientation of the fracture spacer 220 is not limited to this. The protrusion 230 may abut against the lithium-ion secondary battery 1a, and the outer edge 231 may abut against the first end plate 112a. In other words, the first surface 221a of the fracture spacer 220 may face the first end plate 112a, and the second surface 221b may face the wide surface 11b1 of the lithium-ion secondary battery 1a. Alternatively, the second surface 221b of the fracture spacer 220 may face the first end plate 112a, and the first surface 221a may face the wide surface 11b1 of the lithium-ion secondary battery 1a. The joint 232 is the region that connects the protrusion 230 and the outer edge 231. The thickness of the joint 232 is typically made thinner than the thickness of either the protrusion 230 or the outer edge 231. Alternatively, the thicknesses of the protrusion 230 and the outer edge 231 may be the same or different.

[0082] The operation of the aforementioned fracture-type spacer 220 will be explained. For example... Figure 7 As shown, before the lithium-ion secondary battery 1 expands, the protrusion 230 of the fracture spacer 220 abuts against the first end plate 112a. Additionally, the outer edge 231 of the fracture spacer 220 abuts against the wide surface 11b1 of the lithium-ion secondary battery 1a. In this example, there is a gap 400 between the second surface 221b of the protrusion 230 and the wide surface 11b1 of the lithium-ion secondary battery 1a. Furthermore, there is also a gap between the first surface 221a of the outer edge 231 and the first end plate 112a. When a load greater than a predetermined load is applied along the column direction Z (the direction in which the lithium-ion secondary batteries 1 are arranged), the joint 232 breaks. More specifically, if the lithium-ion secondary battery 1 gradually expands, the outer edge 231 abutting against the lithium-ion secondary battery 1a is pushed in the F direction. Furthermore, the first end plate 112a is fixed as a binding member 110. Therefore, the protrusion 230 that abuts against the first end plate 112a is pushed back in the Rr direction. As a result, the joint 232 is sheared and broken. After the joint 232 breaks, the protrusion 230, cut off from the outer edge 231, is pressed into the gap 400 between the second surface 221b side of the protrusion 230 and the wide surface 11b1 of the lithium-ion secondary battery 1a. Figure 8 As shown, the thickness of the fractured spacer 220 decreases accordingly as the protrusion 230 is pressed in. Furthermore, in this example, the outer edge 231 moves in the F direction and abuts against the first end plate 112a.

[0083] The aforementioned fracture spacer 220 includes: a protrusion 230 protruding in a direction in which the wide surfaces 11b1, 11b2 of a plurality of lithium-ion secondary batteries 1 are arranged facing each other; and an outer edge 231 surrounding the protrusion. Furthermore, a joint 232 is provided between the protrusion 230 and the outer edge 231. This joint 232 fractures when a load greater than a predetermined load is applied. Therefore, the thickness of the fracture spacer 220 is reduced. Such a fracture spacer 220 can be constructed from a single component, thus offering the advantage of a smaller number of components.

[0084] Regarding the fracture spacer 220, the load required for the joint 232 to fracture (i.e., the load required when the thickness of the fracture spacer 220 decreases) is typically adjusted by varying the thickness of the joint 232 (in other words, the thickness of the fractured portion). For example, if the thickness of the joint 232 is reduced, the load required for the joint 232 to fracture (in other words, the thickness of the fracture spacer 220 decreases) is reduced. Conversely, if the thickness of the joint 232 is increased, the load required for the joint 232 to fracture increases. The thickness of the joint 232 can be appropriately set by preliminary tests conducted by those skilled in the art. For example, by forming the fracture spacer 220 with a joint 232 thickness of 0.8 mm or more and 1.6 mm or less, a predetermined load can be set to 4 kN to 80 kN. Furthermore, by forming the fracture spacer 220 with a joint 232 thickness of 1.1 mm or more and 2.0 mm or less, a predetermined load can be set to 70 kN to 85 kN. More preferably, by forming the fracture spacer 220 with a thickness of 1.5 mm or more and 3.0 mm or less for the joint 232, the predetermined load can be set to 75 kN to 120 kN. In addition, the fracture spacer 220 can be easily manufactured, for example, by stamping a metal sheet to form a protrusion.

[0085] (Example 2: Spacer 320 in a mating configuration)

[0086] Other preferred examples of the spacer 120 described above may be listed, for example... Figures 9-12 The configuration is as shown. In this example, the fitting spacer 320 has a convex side spacer 330 and a concave side spacer 340. Figure 9 This is a plan view schematically illustrating a preferred embodiment of the spacer 120 disclosed herein (a convex-side spacer 330 in a fitting configuration). In this example, the convex-side spacer 330 has a first surface 330a (the front side surface) and a second surface 330b, which is the back side surface of the first surface 330a. Figure 9 This is a plan view of the convex spacer 330 viewed from the first side 330a. Additionally, Figure 10This is a plan view schematically illustrating a preferred embodiment of the spacer 120 disclosed herein (a recessed-side spacer 340 in a fitting configuration). In this example, the recessed-side spacer 340 has a first surface 340a (the surface side) and a second surface 340b, which is the back surface of the first surface 340a. Figure 10 This is a plan view of the recessed side spacer 340 viewed from the second side 340b. Figure 11 This is a longitudinal sectional view schematically showing the state of the spacer 120 disclosed herein before operation (fitting spacer 320). Additionally, Figure 12 This is a longitudinal sectional view schematically illustrating the state after operation of a preferred embodiment of the spacer disclosed herein (fitting spacer 320). Figure 11 as well as Figure 12 The figure shows the state of the bound lithium-ion secondary battery 1a and the interlocking spacer 320 as viewed from a direction orthogonal to the column direction Z (in this case, the width direction X). Figure 11 The figure shows the spacer 320 (the convex side spacer 330 and the concave side spacer 340) in a state where they are not yet engaged. Figure 12 The diagram shows the... Figure 11 The interlocking spacer 320 is in a state where a load greater than a predetermined load is applied along the column direction Z, and the thickness decreases (in other words, it is in an interlocking state).

[0087] The convex-side spacer 330 is a spacer having a protrusion 332 protruding in a direction in which the wide surfaces 11b1, 11b2 of a plurality of lithium-ion secondary batteries 1 are arranged facing each other. For example... Figure 11 as well as Figure 12 As shown, in this example, the convex-side spacer 330 has a base 331 and a protrusion 332 extending from the base 331. The base 331 is a rectangular plate-like member. The protrusion 332 is a cylindrical protrusion projecting from the base 331. Furthermore, at the end of the protrusion 332, a protrusion 333 is provided, extending in a direction orthogonal to the direction in which the plurality of lithium-ion secondary batteries 1 are arranged facing each other with their wide surfaces 11b1, 11b2. The shape of this protrusion 333 is not particularly limited as long as it does not significantly impair the technical effects of this disclosure. Figure 11 as well as Figure 12 As shown, in this example, the protrusion 333 is rounded. As a result, the recessed side spacer 340 is guided along the curve of the periphery of the protrusion 333, and thus can fit smoothly into the ground.

[0088] The recessed side spacer 340 is a spacer having a recess 341 that receives a protrusion 332. The recess 341 is a depression on an opposing surface (in this example, the second surface 340b) facing the protrusion, provided for the protrusion 332 to engage with it. In this example, the recess 341 is a cylindrical recess with an inner diameter larger than the diameter of the protrusion 333, provided for the protrusion 332 and a protrusion 333 protruding outward from the side of the protrusion 332 to engage with it. Furthermore, a reinforcing claw 342 is provided along the inner circumference at the entrance of the recess 341. This reinforcing claw 342 is a rib extending towards the center from the inner circumferential surface 343 of the recess 341. In this example, the reinforcing claw 342 is continuously provided along the inner circumferential surface 343 of the recess 341. However, the reinforcing claw can also be provided intermittently. Figure 11 as well as Figure 12 As shown, the inner diameter d1 of the reinforced claw 342 is set to be smaller than the inner diameter d2 of the inner circumferential surface 343. Figure 11 The double-layered discontinuous lines shown represent the inner circumferential surface 343 of the recess 341. Furthermore, the inner diameter d2 of the inner circumferential surface 343 is configured to be larger than the maximum outer diameter OD of the protrusion 333, allowing the spacer 330 of the protrusion to enter. This makes the fitted protrusion 333 difficult to disengage, thus increasing its resistance to external forces such as impacts or vibrations.

[0089] The engagement operation of the spacer 320 in the above-described engagement method will be explained. For example... Figure 11 As shown, in this example, the first surface 330a of the convex side spacer 330 is arranged facing the second surface 340b of the concave side spacer 340 along the direction (column direction Z) in which the wide surfaces 11b1 and 11b2 of the plurality of lithium-ion secondary batteries 1 are arranged facing each other. Before the lithium-ion secondary battery 1 expands, the protrusion 333 of the convex side spacer 330 is restrained in a state where it is pushed onto the reinforcing claw 342 of the concave side spacer 340. In addition, in this state, the convex side spacer 330 and the concave side spacer 340 are not yet connected in a fitting manner. Therefore, there is a gap 400 between the convex portion 332 of the convex side spacer 330 and the concave portion 341 of the concave side spacer, which allows the convex portion 332 to be pressed in. When the lithium-ion secondary battery 1 expands and a load greater than a predetermined load is applied, the convex side spacer 330 is pressed in along the column direction Z. Figure 12 As shown, after the lithium-ion secondary battery 1 expands, the convex-side spacer 330 and the concave-side spacer 340 are connected in an interlocking manner. At this time, corresponding to the convex portion 332 being pressed into the gap of the concave portion 341, the distance between the convex-side spacer 330 and the concave-side spacer 340 becomes closer, and thus the thickness of the spacer decreases.

[0090] The aforementioned interlocking spacer 320 includes: a protrusion 332 protruding in a direction in which the wide surfaces 11b1 and 11b2 of a plurality of lithium-ion secondary batteries 1 are arranged facing each other; a recess 341 provided on the facing surface opposite to the protrusion; and a reinforcing claw 342 formed at the entrance of the recess 341 opposite to the protrusion 332. According to this configuration, when a predetermined load is applied, the thickness of the spacer decreases as the protrusion 332 engages with the recess 341. Once the interlocking spacer 320 is activated, the distance between the protrusion 332 and the recess 341 can be instantly reduced. Therefore, it has the advantage of being easily perceived in a management system.

[0091] Regarding the spacer 320 of this fitting method, the fitting load (i.e., the load when the thickness of the spacer 320 decreases) can typically be adjusted by varying the difference (OD - d2) between the maximum outer diameter OD of the protrusion 333 and the inner diameter d2 of the reinforcing claw 342 (the inner diameter of the entrance of the recess 341, i.e., the opening of the recess 341 that is narrowed by the reinforcing claw 342). For example, if the maximum outer diameter OD of the protrusion 333 is decreased (and / or the inner diameter d2 of the reinforcing claw 342 is increased), the difference in the fitting portion decreases, thus reducing the load required for fitting. Conversely, if the maximum outer diameter OD of the protrusion 333 is increased (and / or the inner diameter d2 of the reinforcing claw 342 is decreased), the difference in the fitting portion increases, thus increasing the load required for fitting. The magnitude of this difference in the fitting portion can be appropriately set by those skilled in the art through preliminary tests, etc. For example, by forming the fitting spacer 320 such that the difference between the fitting portions is 0.1 mm or more and 0.6 mm or less, a predetermined load can be set to 4 kN to 30 kN. Furthermore, by forming the fitting spacer 320 such that the difference between the fitting portions is 0.15 mm or more and 0.8 mm or less, a predetermined load can be set to 6 kN to 50 kN. More preferably, by forming the fitting spacer 320 such that the difference between the fitting portions is 0.3 mm or more and 1 mm or less, a predetermined load can be set to 15 kN to 80 kN. Additionally, this fitting spacer 320 can be easily manufactured, for example, by machining a sheet metal to form protrusions and recesses.

[0092] The preferred embodiments of this disclosure have been described above with reference to the accompanying drawings. However, such description is not intended to limit the scope of the invention, and various modifications are certainly possible.

[0093] <Other Implementation Methods>

[0094] The following describes other embodiments using the energy storage module disclosed herein. It is not intended to limit this disclosure to the following description.

[0095] <Energy storage module with multiple spacers>

[0096] As another preferred example of the energy storage module disclosed herein, a configuration having a plurality of spacers 120 can be cited. Figure 13 This is a schematic side view illustrating the energy storage module 101a according to other embodiments disclosed herein. Figure 13 As shown, spacers 120 are disposed at both ends of the plurality of lithium-ion secondary batteries 1 arranged thereon (the first end 2a and the second end 2z of the laminate 2). That is, in this example, spacers 120 are disposed between the lithium-ion secondary battery 1a on the first end 2a side of the laminate 2 and the first end plate 112a. Furthermore, spacers 120 are also disposed between the lithium-ion secondary battery 1z on the second end 2z side and the second end plate 112b. As a result, when a load greater than a predetermined load is applied along the column direction Z, the thickness in the column direction Z can be further reduced. As a result, by further improving the reduction of binding pressure, the situation where electrolyte is squeezed out from the electrode body 20 can be more reliably suppressed.

[0097] As another preferred example, a configuration that causes the spacers at both ends to operate in stages can be listed. Figure 14 This is an explanatory diagram illustrating the operation of the first spacer 120a and the second spacer 120b of the energy storage module 101b according to other embodiments disclosed herein. The energy storage module 100 includes: a first spacer 120a disposed between an energy storage device (here, a lithium-ion secondary battery 1a) on the first end 2a side and a first end plate 112a; and a second spacer 120b disposed between an energy storage device (here, a lithium-ion secondary battery 1z) on the second end 2z side and a second end plate 112b. Here, the thickness of the first spacer 120a decreases when a load greater than a predetermined load is applied along the direction in which the wide surfaces 11b1 and 11b2 of the lithium-ion secondary battery 1 are arranged facing each other (here, the column direction Z). Furthermore, the thickness of the second spacer 120b decreases when a load greater than the load that decreases the thickness of the first spacer 120a is applied along the column direction Z. Figure 14 As shown, due to rapid charging and discharging, multiple energy storage devices (here, lithium-ion secondary batteries 1) gradually expand along the column direction Z. Consequently, the first spacer 120a and the second spacer 120b are pushed along the column direction Z. In this example, firstly, when a large load exceeding a predetermined load (e.g., 4kN to 80kN) is applied, the thickness of the first spacer 120a decreases. Next, when a load larger than the load that causes the thickness of the first spacer 120a to decrease (e.g., 15kN to 80kN) is applied, the thickness of the second spacer 120b decreases. This more reliably suppresses the possibility of electrolyte being forced out of the electrode body 20. Furthermore, it suppresses rapid expansion of the energy storage devices.

[0098] <Encased Energy Storage Module>

[0099] As a preferred embodiment of the energy storage module disclosed herein, examples include... Figure 14 The bag is constructed in the shape shown. Figure 15 This is a schematic perspective view of the encapsulated energy storage module 102 disclosed herein. Figure 15 In order to understand the structure of the enclosed energy storage module 102, it is represented in a partially decomposed state. For example... Figure 14 As shown, multiple energy storage devices (here, lithium-ion secondary batteries 1) are arranged in a direction (here, column direction Z) in which the wide surfaces 11b1 and 11b2 face each other. The encapsulated energy storage module 102 houses multiple lithium-ion secondary batteries 1 inside the binding member 110 (in this example, the casing 210).

[0100] like Figure 15 As shown, the binding member 110 can be, for example, a casing 210. This casing 210 has an upper wall (not shown), a bottom wall 211, a first side wall 212a, a second side wall 212b, a third side wall 213a, and a fourth side wall 213b. Here, the first side wall 212a and the second side wall 212b face each other. The third side wall 213a and the fourth side wall 213b face each other. Inside the casing 210, a stack 2 of multiple lithium-ion secondary batteries 1 arranged in the column direction Z is housed. Furthermore, multiple stacks 2 are arranged in the width direction X, which is orthogonal to the column direction Z. Figure 15 (The middle section has 3 columns, but is not limited to this). The first sidewall 212a and the second sidewall 212b, which extend along the width direction X, can directly support the laminate 2.

[0101] Multiple energy storage devices (laminates 2) have: a first end 2a, which is one end in the direction in which multiple lithium-ion secondary batteries 1 are arranged with their wide surfaces 11b1 and 11b2 facing each other; and a second end 2b, which is opposite to the first end 2a. Here, a spacer 120 is disposed between the lithium-ion secondary battery 1a on the first end 2a side in the column direction Z of each laminate 2 and the binding member 110 (the first sidewall 212a of the casing 210). The thickness of the spacer 120 decreases when a load greater than a predetermined load is applied along the column direction Z.

[0102] In the encapsulated energy storage module 102 described above, multiple lithium-ion secondary batteries 1 (laminates 2) are supported by spacers 120 via the sidewall of the encapsulation 210 (here, the first sidewall 212a). According to this configuration, when the lithium-ion secondary batteries 1 in the laminate 2 expand, the thickness of the spacers 120 decreases. This reduces the binding pressure on the array.

[0103] Furthermore, this encased energy storage module 102 is a so-called Cell-to-Pack (module-less battery pack) structure that directly houses multiple energy storage devices. This Cell-to-Pack structure reduces the number of binding components, thereby improving the volumetric energy efficiency of the module. Alternatively, it can be the aforementioned Cell-Module-Pack (module-based battery pack) structure, which houses the energy storage module 100, including multiple energy storage devices, inside the casing 210.

[0104] <Utilization of Energy Storage Modules>

[0105] There is no particular limitation on the number of energy storage devices contained in the energy storage module disclosed herein. The number of energy storage devices can be appropriately determined according to the intended use of the energy storage module. As examples of the number of energy storage devices, it can be more than 10, more than 20, or more than 30.

[0106] The energy storage module disclosed herein can be used for various applications. However, it is particularly suitable for high-capacity applications (e.g., cell energy density of 500 Wh / L or higher), where the casing is prone to expansion due to rapid charge-discharge cycles. Applications requiring such an energy storage module include, for example, power sources (drive power supplies) for motors in passenger cars, trucks, and other vehicles. Furthermore, the type of vehicle is not particularly limited; examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

[0107] The techniques disclosed herein can be appropriately omitted or combined, provided there are no particular problems. Furthermore, this specification includes the disclosures described in the following items.

[0108] Item 1: An energy storage module, wherein the energy storage module comprises: a plurality of energy storage devices; a binding member; and a spacer, wherein the plurality of energy storage devices have a pair of opposing wide surfaces arranged facing each other, the binding member is configured to bind the plurality of energy storage devices in a direction in which the wide surfaces are arranged facing each other, and the spacer is disposed between an energy storage device disposed at a first end of the arrangement direction and the binding member, wherein the thickness of the spacer decreases when a load greater than a predetermined load is applied along the arrangement direction.

[0109] Item 2: The energy storage module as described in Item 1, wherein the energy storage device has an electrode body and a square housing that houses the electrode body, and the binding member has: a first end plate disposed at a first end in the arrangement direction of the plurality of energy storage devices; a second end plate disposed at a second end on the side opposite to the first end; and a side strip erected between the first end plate and the second end plate, wherein the spacer is disposed between the first end plate and the wide surface of the energy storage device at the first end.

[0110] Item 3: The energy storage module as described in Item 1 or 2, wherein the predetermined load is 4kN or more and 80kN or less.

[0111] Item 4: The energy storage module as described in any one of items 1 to 3, wherein the spacer is rectangular and has: a protrusion protruding in the direction of the arrangement; an outer edge surrounding the protrusion; and a joint connecting the protrusion and the outer edge, wherein the joint is formed to be thinner than the thickness of the protrusion or the outer edge, and the joint breaks when a load greater than a predetermined load is applied along the direction of the arrangement, thereby reducing the thickness.

[0112] Item 5: The energy storage module as described in any one of items 1 to 3, wherein the spacer has: a protrusion protruding in the direction of the arrangement; a recess provided on an opposing surface opposite to the protrusion; and a reinforcing claw formed opposite to the protrusion at the entrance of the recess, wherein the protrusion is configured to form a gap between the protrusion and the recess in a state of contact with the reinforcing claw, and when a load greater than a predetermined load is applied along the direction of the arrangement, the protrusion and the recess engage with each other, thereby reducing the thickness.

[0113] Item 6: The energy storage module as described in any one of items 1 to 5, wherein the spacer is also provided between the energy storage device on the second end side and the second end plate.

Claims

1. An energy storage module, wherein, The above-mentioned energy storage module has the following features: Multiple energy storage devices; Restraining components; and Spacer The aforementioned multiple energy storage devices have a pair of opposing wide surfaces, and these wide surfaces are arranged facing each other. The aforementioned binding member is configured to bind the plurality of energy storage devices in a direction in which the aforementioned wide surfaces are arranged facing each other. The aforementioned spacer is disposed among the aforementioned plurality of energy storage devices, specifically between the energy storage device located at the first end of the aforementioned arrangement direction and the aforementioned restraining member. When a load greater than the predetermined load is applied along the direction of the above arrangement, the thickness of the spacer becomes smaller.

2. The energy storage module as described in claim 1, wherein, The aforementioned energy storage device has an electrode body and a square housing that houses the electrode body. The above-mentioned restraint member has: The first end plate at the first end of the arrangement direction of the plurality of energy storage devices; A second end plate disposed on the second end side located opposite to the first end side; and The side strip installed between the first end plate and the second end plate mentioned above. The aforementioned spacer is disposed between the first end plate and the wide surface of the energy storage device on the first end side.

3. The energy storage module as described in claim 2, wherein, The aforementioned predetermined load is above 4kN and below 80kN.

4. The energy storage module as described in claim 2, wherein, The aforementioned spacer is rectangular and has the following characteristics: A protruding portion in the direction of the above arrangement; The outer edge surrounding the aforementioned protrusion; and The joint that connects the aforementioned protrusion and the aforementioned outer edge. The aforementioned joint is thinner than the aforementioned protrusion or the aforementioned outer edge. When a load greater than the predetermined load is applied along the direction of the above arrangement, the joint breaks, thereby reducing the thickness.

5. The energy storage module as described in claim 2, wherein, The aforementioned spacer has: A protruding portion in the direction of the above arrangement; A recess is provided on the opposing surface opposite to the aforementioned protrusion; and A reinforcing claw portion is formed at the entrance of the recess opposite to the aforementioned protrusion. The aforementioned protrusion is configured to contact the aforementioned reinforcing claw portion, thereby forming a gap between the aforementioned protrusion and the aforementioned recess. When a load greater than the predetermined load is applied along the direction of the above arrangement, the above-mentioned protrusions and the above-mentioned concave parts interlock, thereby reducing the thickness.

6. The energy storage module as described in any one of claims 2 to 5, wherein, The aforementioned spacer is also provided between the energy storage device on the second end side and the second end plate.

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