Battery pack

Abstract

The objective is to obtain a battery pack that can prevent adhesive, which is applied between a battery module consisting of multiple stacked battery cells and a restraining member that holds the multiple battery cells in place, from overflowing and coming into contact with the terminals of the battery cells. [Solution] The battery pack 10 comprises a battery module 12 in which a plurality of battery cells 14, each having a terminal 15 on its upper surface 14U, are stacked in the thickness direction; a restraining member 18 that restrains the plurality of battery cells 14 in the thickness direction; an adhesive G interposed between the side surface 14S of the battery cell 14, which faces a direction perpendicular to the thickness direction in a plan view, and the restraining member 18; and an insulating member 20 in which at least a portion 26 is interposed between the restraining member 18 and the side surface 14S of the battery cell 14 above the adhesive G.

Description

Technical Field

[0001] The present invention relates to a battery pack.

Background Art

[0002] A structure including a battery module in which battery cells and separators are alternately stacked, a restraint band for restraining the battery module, and a heat-absorbing member containing a heat-absorbing agent provided between the restraint band and the battery module has been conventionally known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when an adhesive is provided between the battery module and the restraint band, there is a risk that the adhesive may protrude to the upper surface side of the battery cell during assembly of the restraint band. Since terminals are provided on the upper surface of the battery cell, if the protruding adhesive contacts the terminals of adjacent battery cells, a short circuit will occur.

[0005] Therefore, an object of the present invention is to obtain a battery pack capable of suppressing the adhesive provided between a battery module formed by stacking a plurality of battery cells and a restraint member for restraining the plurality of battery cells from protruding and contacting the terminals of the battery cells.

Means for Solving the Problems

[0006] To achieve the above objective, a battery pack according to a first aspect of the present invention comprises a battery module in which a plurality of battery cells having terminals on their upper surfaces are stacked in the thickness direction, a restraining member that restrains the plurality of battery cells in the thickness direction, an adhesive interposed between the side surface of the battery cell facing a direction perpendicular to the thickness direction in a plan view and the restraining member, and an insulating member in which at least a portion is interposed between the restraining member and the side surface of the battery cell above the adhesive.

[0007] According to the first embodiment of the invention, a battery module is constructed by stacking a plurality of battery cells, each having terminals on its upper surface, in the thickness direction. The plurality of battery cells are constrained in the thickness direction by a restraining member, and an adhesive is interposed between the side surface of each battery cell, which faces a direction perpendicular to the thickness direction in a plan view, and the restraining member.

[0008] Here, at least a portion of the insulating material is interposed between the restraining member above the adhesive and the side surface of each battery cell. Therefore, the insulating material prevents the adhesive from overflowing onto the upper surface of each battery cell. In other words, the adhesive provided between the battery module, which consists of multiple stacked battery cells, and the restraining member that restrains the multiple battery cells, is prevented from overflowing and coming into contact with the terminals of the battery cells.

[0009] Furthermore, a second embodiment of the present invention is a battery pack according to the first embodiment, wherein the insulating member is configured to press the battery cell downward.

[0010] According to the second embodiment of the invention, each battery cell is pressed downward by an insulating member. Therefore, displacement of each battery cell due to external forces applied to the battery module is suppressed.

[0011] Furthermore, a third embodiment of the present invention is a battery pack according to the first or second embodiment, wherein, when viewed from the thickness direction, the upper surface of the insulating member is an inclined surface that slopes outward and downward.

[0012] According to the third embodiment of the invention, the upper surface of the insulating member is an inclined surface that slopes downward and outward when viewed from the thickness direction of the battery cell. Therefore, the insulating member prevents water from entering the upper surface (terminals) of each battery cell.

[0013] Furthermore, a fourth embodiment of the present invention is a battery pack according to the first or second embodiment, wherein the upper surface of the insulating member is formed in a concave shape when viewed from the thickness direction.

[0014] According to the fourth embodiment of the invention, the upper surface of the insulating member is formed in a concave shape when viewed from the thickness direction of the battery cell. Therefore, the insulating member prevents water from entering the upper surface (terminals) of each battery cell. [Effects of the Invention]

[0015] As described above, according to the present invention, it is possible to suppress the adhesive provided between a battery module, which is made up of multiple stacked battery cells, and a restraining member that restrains the multiple battery cells, from overflowing and coming into contact with the terminals of the battery cells. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic front view showing the battery pack according to the first embodiment as viewed from the thickness direction of the battery cells. [Figure 2] This is a schematic front view showing the battery pack according to the second embodiment, viewed from the thickness direction of the battery cells. [Figure 3] This is a schematic front view showing the battery pack according to the third embodiment, viewed from the thickness direction of the battery cells. [Figure 4] This is a schematic front view of a battery pack relating to a comparative example, viewed from the thickness direction of the battery cells. [Modes for carrying out the invention]

[0017] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. For convenience of explanation, in each figure, the arrow UP shown as appropriate is the upward direction of the battery pack, and the arrow RH is the rightward direction of the battery pack. Therefore, in the following description, when the up, down, left, and right directions are described without special mention, they indicate the up, down, left, and right in the battery pack. Also, the thickness direction of the battery cell is the front-back direction of the battery pack, and the front view is when viewed from the front-back direction, but these directions are not particularly limited.

[0018] <First Embodiment> First, the first embodiment will be described. As shown in FIG. 1, the battery pack 10 according to the first embodiment includes a battery module 12 in which a plurality of battery cells 14 are stacked in the thickness direction thereof, and a restraint band 18 as a restraint member that restrains the plurality of battery cells 14 in the thickness direction thereof.

[0019] On both left and right end portions on the upper surface 14U of each battery cell 14 (inside the left-right direction from the pressing portion 24 of the band cover 20 described later), a plus terminal and a minus terminal are provided, respectively. In the following, they are referred to as "terminals 15" without distinguishing between plus and minus. And on the side surface 14S and the lower surface 14D of each battery cell 14 facing the left-right direction (the direction orthogonal to the thickness direction in plan view), insulating films 16 are provided by being attached respectively.

[0020] The restraint band 18 is made of a metal such as aluminum, and is assembled to the outer peripheral portion of the battery module 12 so as to be able to press and restrain each battery cell 14 in the thickness direction. Also, upper overhanging portions 18U and lower overhanging portions 18D that slightly overhang toward the upper surface 14U and the lower surface 14D of each battery cell 14 (toward the inside in the left-right direction) are integrally formed at the upper end portion and the lower end portion of the restraint band 18, respectively.

[0021] An adhesive G is interposed between the side surface 14S of each battery cell 14 (specifically, the film 16, hereinafter referred to as "side surface 14S") and the inner surface of the restraint band 18. The adhesive G is applied and provided at a portion of the side surface 14S of each battery cell 14 excluding the upper end portion 14A. And, between the inner surface of the restraint band 18 and the side surface 14S of each battery cell 14 above the adhesive G, at least a part (insertion portion 26 described later) of the band cover 20 as an insulating member extending in the thickness direction (front-rear direction) of the battery cell 14 is interposed.

[0022] The band cover 20 is made of a material such as mica, for example, and has high insulation and heat resistance. And, this band cover 20 has a fitting portion 22 that is substantially inverted "U" - shaped in a front view and fits onto the upper end portion including the upper overhanging portion 18U of the restraint band 18, a pressing portion 24 that extends integrally downward and inward in the left - right direction from the inner ends in the left - right direction of the fitting portion 22 and presses the upper surface 14U of each battery cell 14 downward, and an insertion portion 26 that is bent substantially at a right angle outward in the left - right direction from the inner ends in the left - right direction of the fitting portion 22 and then bent substantially at a right angle downward and extends integrally, which is substantially inverted "L" - shaped in a front view.

[0023] The width of the lower surface of the fitting portion 22 along the left - right direction is substantially the same as the width along the left - right direction of the upper end portion including the upper overhanging portion 18U of the restraint band 18, and the fitting portion 22 is configured to be fitted and attached (fixed) to the upper end portion including the upper overhanging portion 18U from above. The pressing portion 24 is in contact with the upper surface 14U of each battery cell 14 in a state of being elastically deformed upward, and is configured to press the upper surface 14U of each battery cell 14 downward by its elastic restoring force.

[0024] In a front view, the insertion portion 26 has its lower end 26D bent inward in a roughly crank shape. Therefore, when the insertion portion 26 is inserted between the inner surface of the restraint band 18 and the upper end 14A of the side surface 14S of each battery cell 14, the outer surface of the upper side (bent portion 26U side), excluding the lower end 26D, contacts the inner surface of the restraint band 18 from the lower surface of the upper protrusion 18U, and the insertion is performed with the lower end 26D elastically deformed outward in the left-right direction.

[0025] In other words, the lower end portion 26D of the insertion portion 26 is configured to press the side surface 14S of each battery cell 14 inward in the left-right direction due to its elastic restoring force (the inner surface of the lower end portion 26D contacts the side surface 14S of each battery cell 14 with a predetermined pressure). As a result, the insertion portion 26 of the band cover 20 is interposed between the inner surface of the restraint band 18 above the adhesive G and the side surface 14S of each battery cell 14.

[0026] As shown in Figure 1, the lower end portion 26D of the insertion portion 26 may or may not penetrate into the adhesive G, although this is not shown in the figure. The insertion portion 26 of the band cover 20 can be said to be interposed between the inner surface of the restraint band 18 above the adhesive G and the side surface 14S of each battery cell 14, as long as the upper side (bent portion 26U side), excluding its lower end portion 26D, is in contact with the inner surface of the restraint band 18 above the adhesive G.

[0027] The operation of the battery pack 10 according to the first embodiment, which has the configuration described above, will now be explained.

[0028] First, let's describe the battery pack 100 related to the comparative example shown in Figure 4. This battery pack 100 does not have a band cover 20. Therefore, as shown in Figure 4, when the restraining band 18 is assembled to the outer circumference of the battery module 12, there is a risk that the adhesive G will protrude onto the upper surface 14U of the battery cell 14 and come into contact with the terminal 15. In other words, there is a risk that the adhesive G that protrudes onto the upper surface 14U of the battery cell 14 will come into contact with the terminal 15 of an adjacent battery cell 14 and cause a short circuit.

[0029] In contrast, the battery pack 10 according to the first embodiment is provided with a band cover 20. That is, the insertion portion 26 of the band cover 20 is interposed between the inner surface of the restraint band 18 above the adhesive G and the side surface 14S of each battery cell 14 (which may include the upper end portion 14A to which the adhesive G is not applied).

[0030] Therefore, the insertion portion 26 of the band cover 20 ensures an insulating distance between the restraint band 18 and the side surface 14S of each battery cell 14, thereby preventing or suppressing the adhesive G from overflowing onto the upper surface 14U of each battery cell 14.

[0031] In other words, the adhesive G provided between the battery module 12, which consists of multiple stacked battery cells 14, and the restraining band 18 that constrains the multiple battery cells 14, can be prevented from overflowing and coming into contact with the terminals 15 of adjacent battery cells 14, thereby preventing short circuits.

[0032] Furthermore, the band cover 20 presses the upper surface 14U of each battery cell 14 downward by the elastic restoring force of the pressing portion 24, and presses the side surface 14S of each battery cell 14 inward in the left-right direction by the elastic restoring force of the insertion portion 26 (lower end portion 26D). Therefore, this band cover 20 can suppress or prevent the displacement of each battery cell 14 due to external forces applied to the battery module 12.

[0033] Furthermore, this band cover 20 is made of a material such as mica, and possesses not only insulating properties but also high heat resistance. Therefore, it can suppress or prevent the upper end of the restraining band 18 from melting due to the high-temperature gas generated when the battery cell 14 experiences thermal runaway. In other words, it can suppress or prevent the melted upper end of the restraining band 18 from coming into contact with the terminals 15 of adjacent battery cells 14 and causing a short circuit.

[0034] <Second Embodiment> Next, a second embodiment will be described. Note that parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions (including common functions) will be omitted as appropriate.

[0035] As shown in Figure 2, in this second embodiment, the only difference from the first embodiment is the shape of the fitting portion 22 in the band cover 20. Specifically, when viewed from the thickness direction (front-to-back direction) of the battery cell 14, the upper surface 22U of the fitting portion 22 is an inclined surface that slopes downward and outward in the left-right direction.

[0036] Therefore, the upper surface 22U (inclined surface) of the fitting portion 22 in the band cover 20 can suppress or prevent water W from entering the upper surface 14U (terminal 15) of each battery cell 14. In other words, in the battery module 12, it is possible to suppress or prevent water W from entering the upper surface 14U (terminal 15) of each battery cell 14 and causing a short circuit.

[0037] <Third Embodiment> Finally, a third embodiment will be described. Note that parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions (including common functions) will be omitted as appropriate.

[0038] As shown in Figure 3, in this third embodiment, only the shape of the fitting portion 22 in the band cover 20 differs from that of the first embodiment. Specifically, the upper surface 22U of the fitting portion 22, when viewed from the thickness direction (front-to-back direction) of the battery cell 14, is formed in a concave shape. In other words, a recess 22A extending in the thickness direction of the battery cell 14 is formed in the center of the width direction of the fitting portion 22.

[0039] Therefore, the recess 22A of the fitting portion 22 in the band cover 20 can suppress or prevent water from entering the upper surface 14U (terminal 15) of each battery cell 14. In other words, in the battery module 12, it is possible to suppress or prevent water from entering the upper surface 14U (terminal 15) of each battery cell 14 and causing a short circuit.

[0040] The battery pack 10 according to this embodiment has been described above based on the drawings, but the battery pack 10 according to this embodiment is not limited to the illustrated one, and can be modified as appropriate without departing from the spirit of the present invention. For example, the third embodiment may be applied to the second embodiment. That is, a recess 22A may be formed on the upper surface 22U of the inclined fitting portion 22. [Explanation of symbols]

[0041] 10 battery packs 12 Battery Modules 14 battery cells 14S side 14U top 15 terminals 18 Restraint band (restraint member) 20 Band cover (insulating material) 26 Insertion section (partial) G Adhesive

Claims

1. A battery module comprising multiple battery cells stacked in the thickness direction, each having terminals on its upper surface, A restraining member that restrains multiple battery cells in the thickness direction, An adhesive interposed between the side surface of the battery cell facing a direction perpendicular to the thickness direction in a plan view and the restraining member, An insulating member is interposed between the restraining member and the side surface of the battery cell, at least in part, above the adhesive, A battery pack is included.

2. The battery pack according to claim 1, wherein the insulating member is configured to press the battery cell downward.

3. The battery pack according to claim 1 or claim 2, wherein, when viewed from the thickness direction, the upper surface of the insulating member is an inclined surface that slopes downward and outward.

4. The battery pack according to claim 1 or claim 2, wherein the upper surface of the insulating member is formed in a concave shape when viewed from the thickness direction.

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