Energy storage module and spacers used therein

Abstract

To provide an energy storage module that can stably press on an energy storage device. [Solution] The energy storage module disclosed herein comprises a first energy storage device and a second energy storage device, and a spacer 200. The spacer 200 has a base portion 290, a first uneven structure 210 provided on the first surface 290Rr of the base portion 290 and having a plurality of first protrusions 210p and a first recess 210r, and a second uneven structure 220 provided on the second surface 290F of the base portion 290 and having a second protrusion 220p. The second protrusion 220p of the second uneven structure 220 is provided at a position corresponding to the first recess 210r of the first uneven structure 210.

Description

Technical Field

[0001] The present invention relates to a power storage module and a spacer used therefor.

Background Art

[0002] Conventionally, a power storage module including a plurality of power storage devices arranged along an array direction, a spacer disposed between the plurality of power storage devices, and a restraint mechanism that restrains the plurality of power storage devices and the spacer in the array direction has been widely used (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, as described in Patent Document 1 and the like, a power storage device may expand due to repeated charging and discharging. Particularly in recent high-capacity power storage devices, the expansion tends to be large. As a result, the spacer is likely to have a high compression rate. According to the study by the present inventor, when the compression rate of the spacer becomes high, there is a problem that the expansion of the power storage device cannot be absorbed, and the reaction force on the power storage device and the like increases exponentially and rapidly. Therefore, the spacer is required to absorb the expansion of the power storage device and stably press the power storage device with a predetermined load.

[0005] The present invention has been made in view of the above circumstances, and its main object is to provide a novel power storage module and spacer that can stably press a power storage device.

Means for Solving the Problems

[0006] The present invention discloses an energy storage module comprising a first energy storage device and a second energy storage device arranged along the alignment direction, a spacer disposed between the first energy storage device and the second energy storage device, and a restraining mechanism that restrains the first energy storage device, the second energy storage device and the spacer in the alignment direction. The spacer has a flat plate-shaped base portion having a first surface facing the first energy storage device and a second surface facing the second energy storage device, and configured to be elastically deformable in the alignment direction; a first uneven structure having a plurality of first protrusions provided on the first surface of the base portion and projecting toward the first energy storage device, and a first recess provided between adjacent first protrusions; and a second uneven structure having at least a second protrusion projecting toward the second energy storage device, wherein the second protrusions of the second uneven structure are provided at positions corresponding to the first recesses of the first uneven structure.

[0007] In the above spacer, when the energy storage device expands and a load is applied from the direction of alignment, a tensile force is generated in the base portion between the first projection and the second projection. This tensile action prevents excessive load from being applied to the energy storage device and allows the energy storage device to be pressed stably. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view showing an energy storage module according to one embodiment. [Figure 2] Figure 2 is a schematic perspective view showing the energy storage device shown in Figure 1. [Figure 3] Figure 3 is a schematic longitudinal cross-sectional view along the line III-III in Figure 2. [Figure 4] Figure 4 is a schematic partial perspective view showing a portion of the spacer in Figure 1. [Figure 5] Figure 5 is a partial longitudinal cross-sectional view of the spacer in Figure 4. [Figure 6]Figure 6(A) shows the simulation results with the spacer compressed, and Figure 6(B) is a magnified view of a portion of Figure 6(A). [Figure 7] Figure 7 shows the simulation results illustrating the relationship between the compressibility of the spacer and the reaction force. [Modes for carrying out the invention]

[0009] Hereinafter, preferred embodiments of the energy storage modules disclosed herein will be described with reference to the drawings as appropriate. Matters other than those specifically mentioned herein but necessary for carrying out the present invention (for example, the general configuration and manufacturing process of energy storage modules and devices that do not characterize the present invention) can be understood as design matters for those skilled in the art based on the prior art. The energy storage modules disclosed herein can be carried out based on the contents disclosed herein and common technical knowledge in the art.

[0010] In the following drawings, the same reference numerals are used for members and parts that perform the same function, and redundant explanations may be omitted or simplified. Furthermore, in this specification, the notation "A~B" indicating a range encompasses not only the meaning of A or greater and B or less, but also the meanings of "preferably greater than A" and "preferably less than B".

[0011] Figure 1 is a schematic perspective view showing a power storage module 500 according to one embodiment. The power storage module 500 comprises a plurality of power storage devices (first power storage device and second power storage device) 100 arranged along the array direction X, spacers 200 placed between adjacent power storage devices 100 in the array direction X (between the first power storage device 100 and the second power storage device 100), and a constraint mechanism 300 that constrains the plurality of power storage devices 100 and the spacers 200 in the array direction X. In the following description, the symbols F, Rr, L, R, U, and D in the drawings represent front, back, left, right, up, and down, respectively, and the symbols X, Y, and Z in the drawings represent the thickness direction of the power storage device 100, the width direction perpendicular to the thickness direction, and the height direction perpendicular to the thickness direction and the width direction, respectively. The thickness direction X is also the array direction of the power storage devices 100. However, these are merely directions for explanatory purposes and do not in any way limit the installation configuration of the energy storage module 500.

[0012] The restraint mechanism 300 is a mechanism that restrains a plurality of energy storage devices 100 and spacers 200 in the arrangement direction X. The restraint mechanism 300 is configured to apply a specified restraint load to the plurality of energy storage devices 100 and spacers 200 from the arrangement direction X. The restraint mechanism 300 here comprises a pair of end plates 310, a pair of side plates 320, and a plurality of screws 330. The pair of end plates 310 and the pair of side plates 320 are preferably made of metal. However, the pair of end plates 310 and / or the pair of side plates 320 may be made of resin in part.

[0013] The pair of end plates 310 are positioned at both ends of the energy storage module 500 in the array direction X. The pair of end plates 310 sandwich the multiple energy storage devices 100 and spacers 200 in the array direction X.

[0014] A pair of side plates 320 bridge a pair of end plates 310. The pair of side plates 320 are fixed to the end plates 310 by a plurality of screws 330 such that the restraint load is approximately 10 to 15 kN, for example. Thereby, a restraint load is applied to the plurality of power storage devices 100 and the spacers 200 in the arrangement direction X, and the power storage module 500 is integrally held. However, the configuration of the restraint mechanism is not limited to this. The restraint mechanism 300 may include, for example, a plurality of restraint bands, binding bars, etc. instead of the side plates 320.

[0015] The plurality of power storage devices 100 are arranged side by side along the arrangement direction X (the thickness direction X of the power storage device 100) between the pair of end plates 310. A spacer 200 is disposed between adjacent power storage devices 100 in the arrangement direction X. In the present embodiment, the power storage devices 100 and the spacers 200 are alternately arranged in the arrangement direction X.

[0016] The power storage device 100 is a device capable of repeated charge and discharge. In this specification, the "power storage device" is a concept including secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, and capacitors using chemical reactions such as lithium-ion capacitors and pseudo-capacitance capacitors. Further, the shape, size, number, arrangement, etc. of the plurality of power storage devices 100 constituting the power storage module 500 can be appropriately changed without being limited to the aspects disclosed herein.

[0017] FIG. 2 is a perspective view of the power storage device 100. As can be seen from FIGS. 1 and 2, the plurality of power storage devices 100 are all flat rectangular shapes and are of the same shape here. The plurality of power storage devices 100 are arranged here such that the long side surfaces 12b described later face each other. The plurality of power storage devices 100 are arranged such that the long side surfaces 12b are parallel to each other.

[0018] FIG. 3 is a schematic longitudinal sectional view taken along line III-III of FIG. 2. As shown in FIG. 3, the power storage device 100 includes, here, a battery case 10, an electrode body 20, a positive electrode terminal 30, a negative electrode terminal 40, and an electrolytic solution (not shown). The power storage device 100 is, here, a non-aqueous electrolytic solution secondary battery, and more specifically, a lithium ion secondary battery.

[0019] The battery case 10 is a housing that houses the electrode body 20 and the electrolytic solution. As shown in FIG. 2, the battery case 10 has an outer shape of a flat and bottomed rectangular parallelepiped (rectangular). The material of the battery case 10 may be the same as that conventionally used, and there is no particular limitation. The battery case 10 is preferably made of metal, and more preferably made of, for example, aluminum, an aluminum alloy, iron, an iron alloy, or the like. As shown in FIG. 3, the battery case 10 includes an exterior body 12 having an opening 12h, and a sealing plate (lid body) 14 that seals the opening 12h.

[0020] The exterior body 12 has a bottomed rectangular tube shape, and as shown in FIG. 2, includes a substantially rectangular bottom surface 12a having long sides and short sides, a pair of long side surfaces 12b extending from the long sides of the bottom surface 12a and facing each other, and a pair of short side surfaces 12c extending from the short sides of the bottom surface 12a and facing each other. The bottom surface 12a faces the opening 12h (see FIG. 3). In the present specification, the term "substantially rectangular shape" includes, in addition to a perfect rectangular shape (rectangular shape), for example, a shape in which the corners connecting the long side and the short side of the rectangular shape are R-shaped (rounded corners), a shape having a notch at the corner, and the like.

[0021] The long side surface 12b is a surface facing the spacer 200. As shown in FIG. 2, the long side surface 12b is flat. The long side surface 12b is, here, in direct contact with the spacer 200. However, in other embodiments, it may face the spacer 200 through other members. In plan view, the area of the long side surface 12b is larger than the area of the short side surface 12c. Although not particularly limited, in the case of a high-capacity type used for in-vehicle applications or the like, the area of the long side surface 12b is generally 10,000 mm 2 or more, and preferably 15,000 mm2 The above is preferable, and 20,000 mm 2 The above is more preferable, 25,000 mm 2 The above is even more preferable, 30,000 mm 2 The above are particularly preferable.

[0022] As shown in Figure 1, the sealing plate 14 is substantially rectangular in plan view. As shown in Figure 2, the sealing plate 14 is a plate-like member that extends along the XY plane. As shown in Figure 3, the sealing plate 14 is attached to the outer casing 12 so as to close the opening 12h. The sealing plate 14 faces the bottom surface 12a of the outer casing 12. The sealing plate 14 is substantially rectangular. The battery case 10 is integrated by joining (preferably by welding) the sealing plate 14 to the periphery of the opening 12h of the outer casing 12. The battery case 10 is airtightly sealed.

[0023] As shown in Figure 3, the sealing plate 14 is provided with an electrolyte injection hole 15, a discharge valve 17, and two terminal lead-out holes 18 and 19. The electrolyte injection hole 15 is for injecting electrolyte into the battery case 10 after the sealing plate 14 has been assembled to the outer casing 12. The electrolyte injection hole 15 is sealed by a sealing member 16. The discharge valve 17 is configured to rupture when the pressure inside the battery case 10 exceeds a predetermined value, thereby releasing gas from inside the battery case 10 to the outside. The terminal lead-out holes 18 and 19 penetrate the sealing plate 14 in the height direction Z.

[0024] The positive terminal 30 is located at one end of the sealing plate 14 in the width direction Y (the left end in Figures 2 and 3). The negative terminal 40 is located at the other end of the sealing plate 14 in the width direction Y (the right end in Figures 2 and 3). As shown in Figure 3, the positive terminal 30 and the negative terminal 40 extend from the inside to the outside of the sealing plate 14 through terminal lead holes 18 and 19, respectively. The positive terminal 30 and the negative terminal 40 are crimped to the peripheral portion surrounding the terminal lead holes 18 and 19 of the sealing plate 14 by a crimping process. Crimped portions 30c and 40c are formed at the ends of the outer casing 12 side of the positive terminal 30 and the negative terminal 40 (the lower end in Figure 3). In this way, the positive terminal 30 and the negative terminal 40 are fixed to the sealing plate 14.

[0025] As shown in Figure 3, the positive terminal 30 is electrically connected to the positive tab 23 of the electrode body 20 via the positive current collector 50 inside the casing 12. The positive terminal 30 is insulated from the sealing plate 14 by the internal insulating member 80 and the gasket 90. The negative terminal 40 is electrically connected to the negative tab 25 of the electrode body 20 via the negative current collector 60 inside the casing 12. The negative terminal 40 is insulated from the sealing plate 14 by the internal insulating member 80 and the gasket 90.

[0026] As shown in Figures 2 and 3, plate-shaped positive electrode external conductive members 32 and negative electrode external conductive members 42 are attached to the outer surface of the sealing plate 14. The positive electrode external conductive member 32 is electrically connected to the positive electrode terminal 30. The negative electrode external conductive member 42 is electrically connected to the negative electrode terminal 40. The positive electrode external conductive member 32 and the negative electrode external conductive member 42 are insulated from the sealing plate 14 by an external insulating member 92.

[0027] As shown in Figure 1, the positive electrode external conductive member 32 and the negative electrode external conductive member 42 are equipped with busbars that electrically connect multiple energy storage devices 100 to each other. Here, of two energy storage devices 100 adjacent to each other in the array direction X, the positive electrode external conductive member 32 of one energy storage device 100 and the negative electrode external conductive member 42 of the other energy storage device 100 are electrically connected by the busbars. As a result, the energy storage module 500 is electrically connected in series. However, the method of connecting multiple energy storage devices 100 is not limited to series; for example, they may be connected in parallel, multiple series, multiple parallel, etc.

[0028] The electrode body 20 has a positive electrode and a negative electrode. The configuration of the electrode body 20 may be the same as in the conventional design and is not particularly limited. Also, the number of electrode bodies 20 arranged inside one battery case 10 is not particularly limited and may be one or two or more. In this embodiment, the electrode body 20 is a flat wound electrode body formed by stacking a strip-shaped positive electrode and a strip-shaped negative electrode insulated via a separator and winding them around a winding axis. In this embodiment, the positive electrode has a strip-shaped positive electrode current collector and a positive electrode active material layer provided in a strip shape along the longitudinal direction of the positive electrode current collector. In this embodiment, the negative electrode has a strip-shaped negative electrode current collector and a negative electrode active material layer provided in a strip shape along the longitudinal direction of the negative electrode current collector. However, in other embodiments, the electrode body 20 may be a laminated electrode body in which a plurality of rectangular positive electrodes and a plurality of rectangular negative electrodes are stacked in an insulated state.

[0029] As shown in Figure 3, a positive electrode tab 23 is provided at one end of the electrode body 20 in the winding axis direction (width direction Y in Figure 3). A positive electrode current collector 50 is attached to the positive electrode tab 23. The positive electrode current collector 50 constitutes a conductive path that electrically connects the positive electrode terminal 30 and the positive electrode of the electrode body 20. A negative electrode tab 25 is provided at the other end of the electrode body 20 in the winding axis direction (width direction Y in Figure 3). A negative electrode current collector 60 is attached to the negative electrode tab 25. The negative electrode current collector 60 constitutes a conductive path that electrically connects the negative electrode terminal 40 and the negative electrode of the electrode body 20.

[0030] The electrolyte can be the same as conventional solutions and is not particularly limited. The electrolyte is typically a non-aqueous electrolyte containing a non-aqueous solvent and a supporting salt (electrolyte salt). Examples of non-aqueous solvents include carbonates, esters, ethers, nitriles, sulfones, lactones, etc. These can be used individually or in combination of two or more. Among these, carbonates are preferred. Examples of electrolyte salts include fluorine-containing lithium salts such as lithium hexafluoride phosphate (LiPF6) and lithium tetrafluoroborate (LiBF4). The electrolyte may also contain additives as needed.

[0031] As shown in Figure 1, the spacers 200 are positioned between each of the multiple energy storage devices 100 in the array direction X. However, the spacers 200 only need to be positioned between at least two adjacent energy storage devices 100 (the first energy storage device 100 and the second energy storage device 100) in the array direction X, and do not necessarily need to be positioned between all of the energy storage devices 100. In this embodiment, the spacers 200 are in contact with the long side surface 12b of the energy storage device 100. However, in other embodiments, other materials (for example, conventionally known thermal insulation materials) may be interposed between the energy storage device 100 and the spacers 200.

[0032] In some embodiments, the spacer 200 is preferably insulating. In this specification, "insulating" means that the volume resistivity measured according to JIS K6911:2006 is 1.0 × 10⁻⁶. 10 This means that the resistivity is Ω·cm or greater. The above volume resistivity of spacer 200 is 1.0 × 10⁻⁶ 12 A value of Ω·cm or higher is preferable.

[0033] Figure 4 is a schematic perspective view showing a part of the spacer 200. Figure 5 is a schematic longitudinal cross-sectional view showing a part of the spacer 200. As shown in Figures 4 and 5, the spacer 200 comprises a base portion 290, a first uneven structure 210, and a second uneven structure 220. The base portion 290 is a flat plate-like portion with substantially uniform thickness. Although not particularly limited, the thickness T (average length in the arrangement direction X) of the base portion 290 is preferably about 0.1 to 5 mm, and more preferably 0.3 to 2 mm. Having a base portion 290 improves productivity and workability when arranging the spacer 200 between multiple energy storage devices 100.

[0034] The base portion 290 is an elastic body and is configured to be elastically deformable in the arrangement direction X. The material of the base portion 290 is not particularly limited, but it is preferably made of a polymer material, and more preferably made of rubbers (thermosetting elastomers) such as silicone rubber, fluororubber, urethane rubber, natural rubber, styrene-butadiene rubber, butyl rubber, ethylene propylene rubber (EPM, EPDM), butadiene rubber, isoprene rubber, norbornene rubber, etc. Among these, silicone rubber and EPDM are preferred.

[0035] The base portion 290 has a first surface 290Rr facing the first energy storage device 100 and a second surface 290F facing the second energy storage device 100. The first surface 290Rr and the second surface 290F are, in this case, surfaces facing the long side surface 12b of the energy storage device 100. The first surface 290Rr and the second surface 290F are surfaces that intersect the arrangement direction X, and in Figure 4 they extend along the YZ plane. It is preferable that the width (average length in the width direction Y) and / or height (average length in the height direction Z) of the first surface 290Rr and the second surface 290F are approximately the same as (about ±1 cm) as the opposing surface of the energy storage device 100 (in this case, the long side surface 12b). This makes alignment with the energy storage device 100 easier and improves the productivity and workability of the energy storage module 500.

[0036] The first uneven structure 210 is provided on the first surface 290Rr of the base portion 290. The first uneven structure 210 has a plurality of first protrusions 210p that project toward the first energy storage device 100 side, and a first recess 210r provided between adjacent first protrusions 210p. The first protrusions 210p are erected on the first surface 290Rr of the base portion 290. Here, the first protrusions 210p extend from the first surface 290Rr of the base portion 290 toward the long side surface 12b of the first energy storage device 100.

[0037] The second uneven structure 220 is provided on the second surface 290F (the surface opposite to the first surface 290Rr) of the base portion 290. The second uneven structure 220 has at least a second projection 220p that protrudes toward the second energy storage device 100. Here, the second uneven structure 220 has a plurality of second projections 220p and a second recess 220r provided between adjacent second projections 220p, similar to the first uneven structure 210. The second projections 220p are erected on the second surface 290F of the base portion 290. Here, the second projections 220p extend from the second surface 290F of the base portion 290 toward the long side surface 12b of the second energy storage device 100.

[0038] The first projection 210p and the second projection 220p are formed integrally with the base portion 290. The first projection 210p and the second projection 220p are made of the same material as the base portion 290. However, in other embodiments, the first projection 210p and / or the second projection 220p may be made of a different material from the base portion 290 (for example, a non-elastic resin material, a metal material, a ceramic, etc.). It is preferable that the first projection 210p and the second projection 220p are made of the same material. The shape, size, etc. of the first projection 210p and the second projection 220p can be appropriately changed according to, for example, the shape, size, capacity, constraint load, etc. of the energy storage device 100.

[0039] In this embodiment, the first projection 210p and the second projection 220p are identical in structure, shape, and size. Similarly, the first recess 210r and the second recess 220r are identical in shape and size. Therefore, although the first projection 210p and the first recess 210r of the first uneven structure 210 will be described in detail below as an example, the second projection 220p and the second recess 220r of the second uneven structure 220 can be the same as those of the first uneven structure 210. In the following descriptions of structure, shape, and size, "first projection 210p" can be read as "second projection 220p," and "first recess 210r" can be read as "second recess 220r."

[0040] As shown in Figure 4, the multiple first protrusions 210p are identical in structure, shape, and size. The first protrusions 210p are solid structures (structures filled with contents) without any hollow portions. However, in other embodiments, the first protrusions 210p may be hollow structures, for example, having a peripheral wall portion extending toward the first energy storage device 100 and a hollow portion surrounded by the peripheral wall portion. In that case, the outer shape of the hollow portion may be the same as the outer shape of the first protrusions 210p, or it may be a different shape from the outer shape of the first protrusions 210p.

[0041] In this embodiment, the first projection 210p has an outer shape that is approximately prismatic (approximately square-prism). However, in other embodiments, the outer shape of the first projection 210p may be cylindrical (including elliptical), approximately polygonal prisms other than prismatics (approximately triangular prism, approximately hexagonal prism, etc.), approximately pyramidal, approximately truncated pyramidal, conical, truncated cone, dome, etc. In some embodiments, it is preferable that the outer shape of the first projection 210p is the same as the outer shape of the second projection 220p on the opposite second surface 290F side (manufacturing tolerances etc. are permissible). This makes it easier to apply a balanced load to the opposing energy storage device 100. In this specification, "approximately prismatic" is a term that includes not only a perfect prismatic shape but also shapes such as those in which the corners connecting two sides are rounded (R-shaped, rounded corners), as shown in Figure 4, or shapes with notches at the corners. The same applies to other polygonal prism-like and polygonal shapes described as "approximately ○○-shaped" in this specification.

[0042] As shown in Figure 4, the outer shape of the first projection 210p on the surface facing the energy storage device 100 (facing surface, surface perpendicular to the arrangement direction X) is approximately square. More specifically, it is approximately square. However, in other embodiments, the outer shape of the facing surface of the first projection 210p may be approximately circular, or an approximately polygonal shape other than a square (approximately triangular, rectangular, etc.). In some embodiments, it is preferable that the outer shape of the facing surface of the first projection 210p is a regular polygon or circular. This makes it easier to apply a load in a balanced manner in the direction of the surface. In this specification, "approximately circular" is a term that includes not only a perfect circle (true circle), but also circular shapes where the curvature of the arc differs locally (e.g., an ellipse), and shapes derived from a true circle or circle.

[0043] Although not particularly limited, as shown in Figure 5, the protrusion height D1 (maximum length in the array direction X) of the first projection 210p is preferably greater than the thickness T of the base portion 290 when no load is applied in the array direction X (before being assembled to the energy storage module 500 and compressed by the restraining mechanism 300). This allows the effects of the technology disclosed herein to be realized at a higher level. The protrusion height D1 is preferably about 1 to 10 mm, more preferably 1 to 5 mm, and even more preferably 1 to 3 mm. In some embodiments, the protrusion height D1 of the first projection 210p is preferably the same as the protrusion height D2 of the second projection 220p on the opposite second surface 290F side (manufacturing tolerances etc. are permissible).

[0044] As shown in Figure 5, it is preferable that the width W1 of the first projection 210p in the direction perpendicular to the arrangement direction X (here, the average length in the width direction Y) is greater than the projection height D1. This makes it less likely for the first projection 210p to bend (buckle) in the arrangement direction X. The width W1 of the first projection 210p is preferably about 2 to 30 mm, more preferably 3 to 20 mm, and even more preferably 5 to 10 mm. In some embodiments, it is preferable that the width W1 of the first projection 210p is the same as the width W2 of the second projection 220p on the opposite second surface 290F side (manufacturing tolerances etc. are permissible). In this specification, "width W" refers to the length of the diameter of the circumscribed circle when the opposing surface of the first projection 210p is polygonal, and to the length of the diameter when the opposing surface of the first projection 210p is circular.

[0045] In some embodiments, the ratio (A2 / A1) of the total area A2 of the opposing surfaces of the multiple second protrusions 220p to the total area A1 of the opposing surfaces (upper surfaces) of the multiple first protrusions 210p is preferably 0.5 to 2, and more preferably 1 ± 0.2 (0.8 to 1.2). This allows the effects of the technology disclosed herein to be realized at a higher level. It also makes it easier to apply a load to the energy storage device 100 in a balanced manner. In this specification, "total area A1" refers to the area of ​​the region enclosed by the outer edges of the first protrusions 210p. For example, if the first protrusions 210p have a hollow structure, the area of ​​the hollow portion may also be included in the area. The same applies to the total area A2.

[0046] As shown in Figure 4, the first recess 210r is a roughly prismatic (roughly rectangular prismatic) space surrounded on all sides by four adjacent roughly prismatic first protrusions 210p within the first surface 290Rr. Here, the first recess 210r is partitioned by multiple first protrusions 210p. However, if, for example, the first protrusions 210p are cylindrical, the first recess 210r may not be clearly partitioned by multiple first protrusions 210p, but may be a single continuous space. As shown in Figure 5, the depth of the first recess 210r is the same as the protrusion height D1 of the first protrusions 210p.

[0047] As shown in Figure 5, in the technology disclosed herein, the second projection 220p of the second uneven structure 220 is provided at a position corresponding to the first recess 210r of the first uneven structure 210. The second projection 220p of the second uneven structure 220 is not formed at a position opposite to the first projection 210p of the first uneven structure 210. In this embodiment, the first projection 210p of the first surface 290Rr is provided at a position corresponding to the second recess 220r of the second surface 290F. The first projection 210p of the first uneven structure 210 is not formed at a position opposite to the second projection 220p of the second uneven structure 220. With this configuration, the spacer 200 can stably press the energy storage device 100 with a predetermined restraining load even when the energy storage device 100 expands, and can stably apply the load necessary to maintain performance to the energy storage device 100. This will be explained in detail below.

[0048] Figure 6(A) shows the simulation result of compressing the spacer 200, and Figure 6(B) is a partially enlarged view of Figure 6(A). As shown in Figure 6(A), in this embodiment, when a load is applied from the alignment direction X, the first recess 210r and the second projection 220p are crushed in the alignment direction X, and compressive deformation occurs such that their cross-section expands compared to the state in Figure 5 before compression. As a result, as indicated by the arrows in the partially enlarged view of Figure 6(B), the base portion 290 between the first recess 210r and the second projection 220p is elastically deformed so as to be stretched, and a "tensile" force is generated in the base portion 290. In the spacer 200, this tensile action can suitably absorb the expansion of the energy storage device 100.

[0049] Figure 7 shows the simulation results illustrating the relationship between the compressibility of the spacer 200 and the reaction force. As shown in the simulation results of Figure 7, in the technology disclosed herein, the compressibility of the spacer 200 and the reaction force exhibit a linear proportional relationship. Therefore, even when the energy storage device 100 expands after a charge-discharge cycle and the compressibility of the spacer 200 increases, the relative increase in the reaction force can be suppressed compared to, for example, when the second projection on the second surface side is located at a position corresponding to the first projection on the first surface side. Consequently, the energy storage device 100 can be stably pressed with a predetermined restraining load. Furthermore, since there is no need to enlarge the restraining mechanism in anticipation of an increase in the reaction force, the energy density of the energy storage module 500 can be improved.

[0050] According to the simulation conducted by the present inventor, unlike the technology disclosed herein, for example, as described in Patent Documents 1 and 2, when the spacer does not have a base portion and is corrugated (wavy) in a cross-sectional view, typically, the "compressive deformation" of the corrugated portion is utilized to absorb the expansion of the power storage device. Therefore, when the compression rate of the spacer increases, the reaction force increases exponentially. Also, depending on the thickness of the corrugated portion, so-called buckling may occur, and the transition of the reaction force may become unstable. In contrast, by utilizing the action of "tension" as in the technology disclosed herein, excessive increase in the reaction force can be better suppressed when the compression rate of the spacer 200 becomes large compared to the case of utilizing "compressive deformation".

[0051] From the viewpoint of exhibiting the above-described effects at a higher level, it is preferable that the first recessed portion 210r of the first surface 290Rr is larger than the outer shape of the second protruding portion 220p of the second surface 290F. As shown in FIG. 5, in a cross-sectional view in the arrangement direction X, it is preferable that the width G1 of the first recessed portion 210r is larger than the width W2 of the second protruding portion 220p (W2 < G1). The difference (G1 - W2) between the width G1 of the first recessed portion 210r and the width W2 of the second protruding portion 220p is preferably the same as or larger than the thickness T of the base portion 290. Thereby, a "tensile" force is likely to be generated in the base portion 290, and the above-described effects can be exhibited at a higher level. The above difference (G1 - W2) is preferably 5 times or less, more preferably 3 times or less, still more preferably 2 times or less, and particularly preferably 1.5 times or less of the thickness T of the base portion 290.

[0052] Similarly, it is preferable that the width G2 of the second recessed portion 220r is larger than the width W1 of the first protruding portion 210p (W1 < G2). The difference (G2 - W1) between the width G2 of the second recessed portion 220r and the width W1 of the first protruding portion 210p is preferably the same as or larger than the thickness T of the base portion 290. The above difference (G2 - W1) is preferably 5 times or less, more preferably 3 times or less, still more preferably 2 times or less, and particularly preferably 1.5 times or less of the thickness T of the base portion 290.

[0053] In some embodiments, it is preferable that the second projection 220p of the second uneven structure 220 is provided such that its axis (central axis) coincides with the center of the first recess 210r of the first uneven structure 210.

[0054] In some embodiments, as shown in Figure 4, it is preferable that the multiple first projections 210p are aligned in at least one direction intersecting the arrangement direction X. Here, the multiple first projections 210p are aligned in the width direction Y (first direction) and the height direction Z (second direction) intersecting the arrangement direction X.

[0055] In some embodiments, it is preferable that at least one of the first uneven structure 210 and the second uneven structure 220 is scattered in an island-like (spot-like) manner within the surface so that the multiple protrusions do not come into contact with each other when no load is applied in the alignment direction X. In one example, it is preferable that when no load is applied in the alignment direction X, the multiple first protrusions 210p of the first uneven structure 210 are scattered in an island-like manner within the first surface 290Rr so that they do not come into contact with each other. In other words, it is preferable that a predetermined gap is secured between adjacent first protrusions 210p within the first surface 290Rr, and that the first protrusions 210p and the first recesses 210r are alternately provided in the surface direction. In one example, it is further preferable that when no load is applied in the alignment direction X, the multiple second protrusions 220p of the second uneven structure 220 are scattered in an island-like manner within the second surface 290F so that they do not come into contact with each other. This increases the area of ​​the uneven structure compared to, for example, the case where the first projection 210p and / or the second projection 220p are provided in a rib-like (strip-like) manner, and the effects of the technology disclosed herein can be exhibited at a higher level. In some embodiments, it is preferable that adjacent first projections 210p and / or second projections 220p are arranged so that they do not come into contact with each other even when a load is applied from the arrangement direction X.

[0056] As shown in Figure 4, in this embodiment, the first uneven structure 210 has first protrusions 210p and first recesses 210r arranged regularly (in a predetermined pattern) in the planar direction. More specifically, they are arranged in a checkerboard pattern in plan view. Similarly, the second uneven structure 220 on the opposite side also has second protrusions 220p and second recesses 220r arranged regularly (in a predetermined pattern) in the planar direction. More specifically, they are arranged in a checkerboard pattern in plan view. This allows the effects of the technology disclosed herein to be realized at a higher level.

[0057] The energy storage module 500 can be used for various applications, but it is particularly suitable for use as a power source (driving power supply) for motors mounted on vehicles such as passenger cars and trucks. The type of vehicle is not particularly limited, but examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

[0058] Although preferred embodiments of the present invention have been described above, these embodiments are merely examples. The present invention can be implemented in various other forms. The present invention can be implemented based on the contents disclosed herein and common technical knowledge in the art. The technologies described in the claims include various modifications and changes to the embodiments illustrated above.

[0059] As described above, specific embodiments of the technology disclosed herein include those described in the following sections. Item 1: A storage module comprising: a first energy storage device and a second energy storage device arranged along the direction of arrangement; a spacer disposed between the first energy storage device and the second energy storage device; and a restraining member that restrains the first energy storage device, the second energy storage device and the spacer in the direction of arrangement, wherein the spacer has a flat plate-shaped base portion having a first surface facing the first energy storage device and a second surface facing the second energy storage device, and is configured to be elastically deformable in the direction of arrangement; a first uneven structure having a plurality of first protrusions provided on the first surface of the base portion and projecting toward the first energy storage device, and a first recess provided between adjacent first protrusions; and a second uneven structure having at least a second protrusion projecting toward the second energy storage device, wherein the second protrusions of the second uneven structure are provided at positions corresponding to the first recesses of the first uneven structure. Item 2: The energy storage module according to Item 1, wherein the first recess of the first uneven structure is larger than the outer shape of the second projection of the second uneven structure. Item 3: The energy storage module according to Item 2, wherein, in a cross-sectional view in the direction of arrangement described above, the difference (G1-W2) between the width G1 of the first recess and the width W2 of the second projection is greater than or equal to the thickness of the base. Item 4: The energy storage module according to any one of items 1 to 3, wherein, when no load is applied in the direction of the arrangement described above, the plurality of first protrusions of the first uneven structure are scattered within the first surface so as not to come into contact with each other. Item 5: The energy storage module according to any one of items 1 to 4, wherein in the first uneven structure, the first protrusion and the first recess are arranged in a checkerboard pattern when viewed from above. Item 6: A spacer for an energy storage module, which is disposed between a first energy storage device and a second energy storage device arranged along the direction of arrangement, comprising: a flat plate-shaped base portion having a first surface facing the first energy storage device and a second surface facing the second energy storage device, and configured to be elastically deformable in the direction of arrangement; a first uneven structure provided on the first surface of the base portion, having a plurality of first protrusions projecting toward the first energy storage device and a first recess provided between adjacent first protrusions; and a second uneven structure provided on the second surface of the base portion, having at least a second protrusion projecting toward the second energy storage device, wherein the second protrusions of the second uneven structure are provided at positions corresponding to the first recesses of the first uneven structure. [Explanation of Symbols]

[0060] 10 Battery Case 20 Electrode body 100 Energy Storage Devices 200 Spacer 210 First uneven structure 210p 1st protrusion 210r First depression 220 Second uneven structure 220p 2nd protrusion 220r Second depression 290 Base section 300 Restraint mechanism 500 Energy Storage Modules X Thickness direction (arrangement direction)

Claims

1. A first energy storage device and a second energy storage device arranged along the direction of the arrangement, A spacer is placed between the first energy storage device and the second energy storage device, A restraining mechanism that restrains the first energy storage device, the second energy storage device, and the spacer in the direction of arrangement, Equipped with, The previous spacer is A flat plate-shaped base portion having a first surface facing the first energy storage device and a second surface facing the second energy storage device, and configured to be elastically deformable in the direction of the arrangement, A first uneven structure having a plurality of first protrusions provided on the first surface of the base portion and projecting toward the first energy storage device, and a first recess provided between adjacent first protrusions, A second uneven structure is provided on the second surface of the base portion and has a second projection that protrudes at least toward the second energy storage device side, It has, The second projection of the second uneven structure is provided at a position corresponding to the first recess of the first uneven structure. Energy storage module.

2. The first recess of the first uneven structure is larger than the outer shape of the second projection of the second uneven structure. The energy storage module according to claim 1.

3. In a cross-sectional view in the direction of arrangement, the difference (G1-W2) between the width G1 of the first recess and the width W2 of the second projection is greater than or equal to the thickness of the base portion. The energy storage module according to claim 2.

4. At least in a state where no load is applied in the direction of the arrangement, the plurality of first protrusions of the first uneven structure are scattered within the first surface so as not to come into contact with each other. The energy storage module according to claim 1.

5. In the first uneven structure, the first protrusions and the first recesses are arranged in a checkerboard pattern when viewed from above. The energy storage module according to claim 1.

6. A spacer for an energy storage module, which is positioned between a first energy storage device and a second energy storage device arranged along the direction of arrangement, A flat plate-shaped base portion having a first surface facing the first energy storage device and a second surface facing the second energy storage device, and configured to be elastically deformable in the direction of the arrangement, A first uneven structure having a plurality of first protrusions provided on the first surface of the base portion and projecting toward the first energy storage device, and a first recess provided between adjacent first protrusions, A second uneven structure is provided on the second surface of the base portion and has a second projection that protrudes at least toward the second energy storage device side, It has, The second projection of the second uneven structure is provided at a position corresponding to the first recess of the first uneven structure. Spacers for energy storage modules.

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