Restraint structure and battery structure body

Abstract

To provide a restraint structure and a battery structure body that absorbs external shocks (external forces) to maintain battery performance and ensure safety.SOLUTION: A restraint structure and a battery structure body each include a pair of clamping members that clamp, from a first direction, a storage module in which multiple storage cells are stacked in a first direction, and an external force absorbing member that is provided on the clamping members and absorbs external forces applied from a direction intersecting the first direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a restraint structure and a battery structure.

Background Art

[0002] A power storage module formed by electrically connecting a plurality of power storage cells has come to be widely used as a high-output power source. In a power storage module, in order to stably exhibit the performance and life of the battery, etc., a restraint load may be applied to the power storage cells.

[0003] As a technique for applying a restraint load, a power storage module has been disclosed in which a pressurizing mechanism for pressing in the stacking direction of the battery is provided, so that a stable restraint load can be applied even when the thickness of the power storage cell changes, and the performance of the battery can be exhibited. Further, a power storage device in which a power storage module is restrained by a restraint member has been disclosed (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Documents 1 and 2, although it is effective for eliminating fluctuations in the restraint load associated with volume changes in the power storage cells and fixing the power storage module, for example, there is room for improvement in maintaining good battery performance when an external force is applied due to dropping of the power storage module itself, collision with flying objects, etc.

[0006] The present disclosure has been made in view of the above. An object to be solved by one embodiment of the present disclosure is to provide a restraint structure and a battery structure that absorb external impact (external force) and maintain battery performance.

Means for Solving the Problems

[0007] Specific means for solving the problems include the following aspects. <1> A restraint structure including a pair of sandwiching members that sandwich a power storage module in which a plurality of power storage cells are stacked in a first direction, and an external force absorbing member provided in the sandwiching members that absorbs an external force applied from a direction intersecting the first direction. <2> The external force absorbing member extends from an end face of the sandwiching member inward in a second direction orthogonal to the first direction, and has a shape in which a cross section along the second direction becomes thinner continuously or stepwise from the end face toward the inside. The restraint structure according to <1>. <3> The external force absorbing member has a circular or elliptical cross-sectional shape in a direction orthogonal to the second direction. The restraint structure according to <1> or <2>. <4> The sandwiching member has at least a hollow portion and a partition wall alternately in the second direction, the partition wall penetrates between the hollow portions, and has a hole into which the external force absorbing member is inserted. The restraint structure according to any one of <1> to <3>. <5> A battery structure including a power storage module including a plurality of power storage cells stacked in a first direction, and the restraint structure according to any one of <1> to <4>.

Advantages of the Invention

[0008] According to one embodiment of the present invention, a restraint structure and a battery structure that absorb external impact (external force) and maintain battery performance are provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0010] Hereinafter, the battery structure of the present disclosure will be described with reference to the drawings, and the restraint structure will also be described in detail through this description. Note that the drawings are schematically shown, and the size and shape of each part are appropriately exaggerated for easy understanding.

[0011] In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, a numerical range indicated by using "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of the numerical range of other stepwise descriptions.

[0012] A battery structure according to an embodiment of the present disclosure includes a power storage module including a plurality of power storage cells stacked in a first direction, and a restraint structure. The restraint structure of the present disclosure includes a pair of sandwiching members that sandwich the power storage module in which the plurality of power storage cells are stacked in the first direction from the first direction, and an external force absorbing member provided in the sandwiching member that absorbs an external force applied from a direction intersecting the first direction.

[0013] The battery structure according to an embodiment of the present disclosure includes a restraint structure that restrains and fixes the battery module, and an external force absorption member of the restraint structure acts to absorb the external force received when the power storage module falls from a high place or the like, thereby mitigating the impact on the power storage module. As a result, the battery performance can be stably maintained. Such an effect is presumably due to the following reasons, but is not limited thereto. In the battery structure, while a plurality of power storage cells are fixed by being sandwiched by a sandwiching member under a pressing action in a first direction which is the stacking direction thereof, when an external impact (external force) is applied in a direction intersecting the first direction, the external force absorption member absorbs the external force and mitigates the external force applied to the power storage module. It is considered that this is because the structure of the power storage module can be stably maintained without being damaged.

[0014] An embodiment of the battery structure of the present disclosure will be specifically described with reference to FIGS. 1 to 7. However, the present disclosure is not limited to the embodiments shown below. Also, in the drawings, the same or corresponding parts are denoted by the same reference numerals and the description thereof is omitted.

[0015] An embodiment of the battery structure of the present disclosure is shown in FIGS. 1 and 2. FIG. 1 is a schematic perspective view schematically showing an embodiment of the battery structure of the present disclosure, and FIG. 2 is a cross-sectional view taken along line C-C of FIG. 1 (the external force absorption member is not shown), and is a schematic side view showing a state in which the power storage module 10 in the battery structure is sandwiched between a pair of sandwiching members 13.

[0016] As shown in FIG. 1, the battery structure 100 includes a power storage module 10, a pair of sandwiching members 13 disposed to sandwich the power storage module 10, a restraint member 21 that restrains the pair of sandwiching members 13, and an external force absorption member 17 disposed inside the sandwiching member 13.

[0017] As shown in FIGS. 1 and 2, the clamping member 13 is arranged in contact with two main surfaces located at both ends of the power storage module 10 in the first direction, and sandwiches the power storage module 10 from the first direction. Surface pressure is applied to the two main surfaces of the power storage module 10 by a pair of clamping members 13, and the power storage module is fixed. Each clamping member is formed in a flat plate shape. The outer shape of each clamping member in plan view is larger than the outer shape of the power storage module in plan view. Note that the "two main surfaces" of the power storage module refer to two wide surfaces that intersect the direction in which the power storage module and the pair of clamping members are stacked among the plurality of surfaces.

[0018] The clamping member 13 is composed of two metal plates 14 and a plurality of hollow square pipes 15 clamped between the metal plates 14, and a hollow portion is formed. The hollow portions are provided in plurality at equal intervals by arranging a plurality of hollow square pipes 15 in the second direction. The hollow portions may be formed using metal materials such as, for example, H-beams and general-purpose frames (e.g., aluminum frames) in addition to square pipes. Further, the hollow portions may be formed using resin, and as the resin, a resin that is difficult to plastically deform is preferable. The clamping member 13 preferably has a plurality of hollow portions partitioned by partition walls at least in the second direction. The hollow portions preferably have a rectangular shape in side view as shown in FIG. 2 or FIG. 5 from the viewpoint of making the pressure applied to the power storage module 10 uneven by weighting the regions with hollow portions and the regions without hollow portions during pressurization. The hollow portions in the clamping member 13 are spaces partitioned by the wall portions (also referred to as partition walls) of the hollow square pipes 15, and the partition walls separating between the hollow portions are preferably provided with holes 16 (see FIGS. 4 to 5) through which the external force absorbing member 17 enters while communicating between the hollow portions. Among them, the clamping member 13 is preferably a hollow metal member in terms of being easily absorb the external force when the external force absorbing member 17 is pushed into the hole 16. Aluminum (Al) etc. are preferably cited as the metal. Further, resin may be used instead of the metal material, and a hollow resin member formed by molding may be used as the clamping member 13. As the resin, a resin that is difficult to plastically deform may be appropriately selected according to the purpose etc., and examples thereof include polyester and polycarbonate. In the present disclosure, the clamping member preferably includes a portion having hollow portions and partition walls alternately at least in the second direction, and the partition walls penetrate between the hollow portions and have holes 16 into which the external force absorbing member 17 is inserted.

[0019] FIG. 3 schematically shows the appearance of the battery structure shown in FIG. 1 in plan view. FIG. 4 is a cross-sectional view taken along line A-A of FIG. 2, and FIG. 5 is a cross-sectional view taken along line B-B of FIG. 3. FIGS. 4 and 5 show a state in which the external force absorbing member 17 is attached to the clamping member 13.

[0020] The external force absorbing member 17 is disposed inside each of the pair of clamping members 13 and absorbs an external force applied from a direction intersecting the first direction. The direction intersecting the first direction may be any direction having an inclination angle with the first direction, and the external force received from this direction is absorbed while being transmitted in the second direction in the external force absorbing member. As shown in FIGS. 3 and 4, the external force absorbing member 17 is provided along the second direction orthogonal to the first direction. The external force absorbing member 17 is provided inward from both end sides of the clamping member 13 in the second direction, and a plurality of them are arranged at equal intervals in the third direction orthogonal to the second direction. The external force absorbing member 17 is provided in a protruding state with a length corresponding to a stroke that is pushed into the clamping member inward in the second direction (the direction of the arrow in FIG. 4) when an external force is received outside the clamping member 13.

[0021] That the second direction is "orthogonal to the first direction" includes not only the case where the first direction and the second direction intersect perpendicularly (90°), but also the case where they have an inclination angle θ (-5° ≤ θ ≤ 5°) that appears to intersect perpendicularly. Equal intervals means not only the case where the intervals are exactly equal, but also an error generally acceptable in the technical field of the present disclosure and not contrary to the gist of the technology of the present disclosure (for example, an error of about 1% to 10%).

[0022] The external force absorbing member 17 extends inward from one end face of the clamping member 13 in the second direction and further extends inward from the other end face. The external force absorbing member extending from one end face of the clamping member 13 and the external force absorbing member extending from the other end face of the clamping member 13 are alternately arranged so that their positions in the third direction do not overlap as shown in FIGS. 3 to 4.

[0023] The cross-section of the external-force absorbing member 17 along the second direction is a tapered shape that continuously narrows inward from one end face and the other end face respectively. That is, the cross-sectional diameter gradually decreases from one end in the longitudinal direction (the side where the cross-sectional diameter of the cross-section perpendicular to the longitudinal direction is large) to the other end (the side where the cross-sectional diameter is small). Thereby, when receiving an external impact from the outside, as shown in FIG. 6, the external-force absorbing member 17 is pressed by the external force, and the pressed external-force absorbing member 17 enters from each end face into the interior. When the external-force absorbing member 17 enters the interior, since the external-force absorbing member has a tapered shape, while penetrating through the partition wall that separates the hollow space of the sandwiching member 13, the hole 16 provided in the partition wall is expanded. Specifically, the pressed external-force absorbing member 17 advances within the hole 16, and the hole 17 is expanded by the external-force absorbing member 17 as shown in FIG. 7. At this time, the external force in the second direction applied to the external-force absorbing member 17 is converted into the force in the direction of the arrow in FIG. 7 as it advances within the hole, and the force in the second direction is relaxed. Thereby, the structural breakage of the power storage module due to the external force during impact can be suppressed, and the battery performance can be maintained well.

[0024] The shape of the cross-section of the external-force absorbing member along the second direction (longitudinal direction) is not limited to a tapered shape, and may be a shape that gradually narrows in a stepped manner from one end in the longitudinal direction (the side where the cross-sectional area of the cross-section perpendicular to the longitudinal direction is large) to the other end (the side where the cross-sectional area is small). That is, even if the cross-sectional area decreases stepwise in multiple steps, an external-force relaxation effect similar to the above-mentioned tapered shape can be expected.

[0025] The external-force absorbing member 17 may be either a solid structure or a hollow structure, and from the viewpoint of converting and dispersing the external force in the second direction as shown in FIG. 7, it is preferably a member with a solid structure.

[0026] The shape of the cross-section of the external-force absorbing member 17 perpendicular to the second direction is not particularly limited, and examples include a rectangle, a trapezoid, a circle, or an ellipse. From the viewpoint of dispersing the external force evenly (preferably equally) in a plane direction perpendicular to the second direction as shown in FIG. 7, it is preferably a circle or an ellipse. The shape and diameter of the hole 16 can be appropriately set according to the shape of the external force absorbing member 17.

[0027] A pressure plate 18 is attached to the external force absorbing member 17. The pressure plate 18 is joined to a plurality of external force absorbing members 17, and is configured to disperse the external force applied during impact so that the external force applied to the power storage module does not locally concentrate. There is no particular limitation on the number of external force absorbing members attached to a single pressure plate 18, and it may be appropriately selected according to the purpose or the like.

[0028] The power storage module 10 has a battery structure in which a plurality of power storage cells are stacked. The plurality of power storage cells are stacked along the direction in which the power storage module 10 and the sandwiching member 13 are stacked. The power storage module may be a monopolar battery in which a plurality of power storage cells are electrically connected to each other by a conductive member (such as a bus bar). Further, the power storage module is preferably, for example, a bipolar battery in which an electrode body having a positive electrode layer on the surface of the positive electrode current collector, which is one surface of a current collector in which a negative electrode current collector and a positive electrode current collector are stacked, and a negative electrode layer on the surface of the negative electrode current collector, which is the other surface, is stacked with a separator interposed therebetween.

[0029] The power storage module 10 is a rectangular battery and has a configuration in which flat rectangular power storage cells are stacked. The power storage module may be, for example, rectangular in plan view with one side being 0.2 m or more. Further, the power storage module is not limited to a rectangular shape and may be a cylindrical battery.

[0030] The plurality of power storage cells may be rechargeable secondary batteries (for example, lithium ion secondary batteries). The secondary batteries include secondary batteries provided with an electrolytic solution and solid batteries using a solid electrolyte. The solid batteries include all solid batteries having a solid electrolyte layer instead of an electrolytic solution, and the solid electrolyte may contain an electrolytic solution of less than 10% by mass with respect to the total amount of the electrolyte.

[0031] The structure of the storage battery cell is not particularly limited and can be appropriately selected. The power generation element includes, for example, a positive electrode, a negative electrode, a separator that insulates between the positive electrode and the negative electrode, and an electrolyte. The positive electrode, the separator, and the negative electrode may be stacked and arranged in the first direction. Each of the positive electrode and the negative electrode contains an active material capable of reversibly storing and releasing charge carriers. The separator is preferably a porous sheet containing a resin (for example, polyethylene (PE), polypropylene (PP), polyester, cellulose, polyamide). The electrolyte preferably contains, for example, a non-aqueous solvent and a supporting salt such as a lithium salt.

[0032] As shown in FIG. 1, the restraint member 21 is disposed on both end sides of the sandwiching member 13 in the third direction and is fixed to the pair of sandwiching members 13. Pressure is applied to the pair of sandwiching members 13 by the restraint member 21, and the storage battery module 10 is subjected to surface pressure by the sandwiching members 13.

[0033] In the above-described embodiment, the case where three external force absorbing members are arranged at one end of the sandwiching member and four external force absorbing members are arranged at the other end is described as an example. However, the restraint member of the present disclosure is not limited to this mode, and the external force absorbing members can be provided in an appropriate quantity and positional relationship according to the purpose, such as the size of the storage battery module, the size of the external force absorbing members, and the external force absorbing ability, and the applied external force.

Explanation of Reference Numerals

[0034] 10... Storage battery module 12... Storage battery cell 13... Sandwiching member 17... External force absorbing member 21... Restraint member 100... Battery structure

Claims

1. A pair of clamping members that clamp a power storage module in which a plurality of power storage cells are stacked in a first direction from the first direction, an external force absorbing member provided in the clamping member and configured to absorb an external force applied from a direction intersecting the first direction, and a restraint structure including the same.

2. The external force absorbing member extends from an end surface of the clamping member inward in a second direction orthogonal to the first direction, and has a shape in which a cross section along the second direction becomes thinner continuously or stepwise from the end surface toward the inside. The restraint structure according to claim 1.

3. The external force absorbing member has a circular or elliptical cross-sectional shape in a direction orthogonal to the second direction. The restraint structure according to claim 2.

4. The clamping member has at least a hollow portion and a partition wall alternately in the second direction, The partition wall penetrates between the hollow portions and has a hole into which the external force absorbing member is inserted. The restraint structure according to claim 1.

5. A power storage module including a plurality of power storage cells stacked in a first direction, the restraint structure according to any one of claims 1 to 4, and a battery structure including the same.

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