Power storage unit and power storage device

Abstract

Provided is a power storage unit capable of suppressing a decrease in cooling efficiency and a power storage device provided with the power storage unit. The power storage unit is provided with: a plurality of electrode bodies that are rectangular in a cross-sectional view observed from a long side direction; a wall member that is "I"-shaped in a cross-sectional view observed from the long side direction and is interposed between the plurality of electrode bodies; and a case that accommodates the electrode bodies and the wall member. Further, the power storage device is provided with: the power storage unit; and a heat conduction member that is provided on an outer surface of a bottom wall of the case that extends along the long side direction.

Description

Technical Field

[0001] This invention relates to an energy storage unit and an energy storage device. Background Technology

[0002] A battery pack is known in the past, which is configured to have multiple rechargeable secondary batteries arranged in a predetermined direction in an electrically connected state and constrained under a load applied in that arrangement direction (for example, see Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-157747 Summary of the Invention

[0004] Furthermore, due to repeated charging and discharging, the sidewalls (ventral side) of the battery casing sometimes expand and deform. This expansion and deformation, coupled with the contraction and deformation of the bottom wall of the casing, can reduce the contact between the bottom wall and the heat-conducting components. In other words, it can potentially reduce the cooling efficiency of the battery casing. Therefore, there is still room for improvement in the structure that mitigates the decrease in cooling efficiency of the battery casing.

[0005] Therefore, the object of the present invention is to obtain an energy storage unit capable of suppressing the decline in cooling efficiency and an energy storage device having the energy storage unit.

[0006] To achieve the above objectives, the energy storage unit according to the first aspect of the present invention comprises: a plurality of electrode bodies that are rectangular in shape in a cross-sectional view viewed from the long side direction; a wall member that is I-shaped in a cross-sectional view viewed from the long side direction and is located between the plurality of electrode bodies; and a housing that accommodates the electrode bodies and the wall member.

[0007] According to the invention of the first aspect, a plurality of electrode bodies, which are rectangular in shape in a cross-sectional view viewed from the long side, are housed in a housing, and a wall member, which is I-shaped in shape in a cross-sectional view viewed from the long side and is also housed in the housing, is located between the plurality of electrode bodies. Therefore, the bottom and top walls of the housing are reinforced by the wall member.

[0008] That is, even if the sidewall (ventral side) of the casing extending along the long side of the energy storage unit expands and deforms outward due to repeated charging and discharging, the contraction deformation of the bottom and top walls of the casing, such as inward concavation in the vertical direction, is suppressed. As a result, for example, the decrease in contact with the heat-conducting components provided on the outer surface of the bottom wall of the casing is suppressed, and the cooling efficiency of the energy storage unit is suppressed.

[0009] Furthermore, the energy storage unit of the second aspect of the present invention is the energy storage unit of the first aspect, wherein an insulating film is provided on the bottom wall, top wall and side wall of the electrode body extending along the long side direction.

[0010] According to the invention of the second aspect, an insulating film is provided on the bottom wall, top wall, and side wall of the electrode body extending along its long side. Therefore, even if the wall components are made of metal, short circuits caused by contact between the electrode body and the wall components are prevented.

[0011] Furthermore, the energy storage unit of the third aspect of the present invention is the energy storage unit of the second aspect, wherein the length of the wall member along the long side direction is set to be shorter than the length of the insulating film along the long side direction, and the insulating films on the plurality of adjacent electrode bodies located further outward of the long side direction than the wall member are joined to each other.

[0012] According to the invention of the third aspect, the length of the wall member along its long side is set to be shorter than the length of the insulating film along its long side. Furthermore, the insulating films on a plurality of adjacent electrode bodies located further outward along the long side than the wall member are bonded to each other. Therefore, movement of the wall member along its long side is suppressed or prevented, and even if the wall member is made of metal, short circuits caused by contact between the electrode bodies and the wall member are prevented.

[0013] Furthermore, the energy storage device according to the fourth aspect of the present invention includes: an energy storage unit of any one of the first to third aspects; and a heat-conducting component disposed on the outer surface of the bottom wall of the housing extending along the long side direction.

[0014] According to the fourth embodiment of the invention, a heat-conducting component is provided on the outer surface of the bottom wall of the housing in the energy storage unit. Therefore, the energy storage unit dissipates heat efficiently, and the decrease in the cooling efficiency of the energy storage unit is suppressed.

[0015] Invention Effects

[0016] As described above, according to the present invention, the decrease in cooling efficiency of the energy storage unit can be suppressed. Attached Figure Description

[0017] Figure 1 This is a schematic perspective view showing the energy storage unit involved in this embodiment.

[0018] Figure 2 This is a schematic perspective view showing the electrode body provided with an insulating film according to this embodiment.

[0019] Figure 3 This is a schematic cross-sectional view of the energy storage unit involved in this embodiment, viewed from the long side.

[0020] Figure 4 This is a schematic perspective view of the plate involved in this embodiment.

[0021] Figure 5 yes Figure 3 A simplified cross-sectional view of the XX line in the diagram.

[0022] Figure 6 This is a schematic top view showing the electrode body and plate with an insulating film provided according to this embodiment. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, for ease of explanation, arrow UP is appropriately shown in each figure as the upward direction of the energy storage unit, arrow FR as the forward direction of the energy storage unit, and arrow LH as the left direction of the energy storage unit. Therefore, in the following description, unless otherwise specified, the directions up / down, front / back, and left / right refer to the up / down, front / back, and left / right directions within the energy storage unit, but are not limited to these directions.

[0024] like Figure 1 As shown, the energy storage unit 10 involved in this embodiment is, for example, a square lithium-ion secondary battery, and includes an electrode body 22 (see reference). Figure 2 ), as a wall component, plate 30 (reference) Figure 4 The system includes a housing 12 that accommodates the electrode bodies 22 and the plate 30. The housing 12 and the plate 30 are made of a metal such as aluminum alloy. In this embodiment, an example accommodating two electrode bodies 22 and one plate 30 will be described.

[0025] like Figure 1 As shown, the housing 12 has: a bottom wall 14, which is a rectangular plate with the left-right direction as the long side direction; and a pair of front and rear side walls 18, which are integrally erected at a predetermined height on the long side of the bottom wall 14. That is, the pair of front and rear side walls 18 are respectively formed as rectangular plates with the left-right direction as the long side direction and the up-down direction as the short side direction.

[0026] Furthermore, protrusions 16A are integrally formed at the upper ends (the ends opposite to the bottom wall 14) of the front and rear side walls 18, extending and abutting each other in a direction that approaches each other, and these protrusions 16A constitute the top wall 16 of the housing 12. In addition, the left and right ends of the housing 12 are open, and the openings are closed by the terminal portions 15 described later.

[0027] like Figure 5 As shown, the terminal portion 15 is made of metal and has: a fitting portion 15A, which is a slightly rectangular block that can be inserted into the openings at the left and right ends of the housing 12; and a flange portion 15B, which is integrally formed on the outer surface of the fitting portion 15A, and whose inner surface can abut against the opening end face in the housing 12.

[0028] Therefore, the terminal portion 15 is designed to close the opening of the housing 12 by inserting its fitting portion 15A into the opening of the housing 12 and having the inner surface of its flange portion 15B abut against the opening end face of the housing 12. Additionally, an electrode terminal 15C with a predetermined protrusion height that is approximately rectangular when viewed from the long side direction (left-right direction) is integrally provided on the outer surface of the fitting portion 15A (terminal portion 15). Figure 1 ).

[0029] like Figure 2 As shown, the electrode body 22 is formed as a rectangular block with its long side in the left-right direction and its thickness in the front-back direction. That is, the electrode body 22 is formed as a rectangle that is longer in the vertical direction in a cross-sectional view viewed from the long side direction. Moreover, an insulating film 20 formed of non-stretched polypropylene (CPP) resin material with a specified thickness (e.g., 100 μm to 110 μm) is provided on the bottom wall 24, top wall 26, and front and back side walls 28 extending along the long side direction of the electrode body 22, covering approximately the entire surface.

[0030] More specifically, the insulating film 20 is wound to cover the bottom wall 24, top wall 26, and front and rear side walls 28 of the electrode body 22 extending along its long side. The portions of the top wall 26 that overlap each other are heat-fused at three intervals along the long side, thereby being installed on the electrode body 22. That is, the electrode body 22 has a structure in which the insulating film 20 is not provided on the left and right side walls 25 that are electrically connected to the terminal portion 15.

[0031] like Figure 3 As shown, inside the housing 12, two electrode bodies 22, each wrapped with an insulating film 20, are arranged in the thickness direction along the front-back direction and are housed therein, with the plate 30 positioned between the two parallel electrode bodies 22. In other words, with the electrode bodies 22 arranged on both the front and back sides of the plate 30, the plate 30 and the electrode bodies 22 are housed within the housing 12.

[0032] like Figure 4 As shown, the plate 30 is formed in an "I" shape in a cross-sectional view viewed from the long side direction, and has: a main body 32, which is a rectangular plate extending along the long side direction at a height higher than the height of the electrode body 22; a lower extension 34, which extends integrally from the lower end of the main body 32 in the front-rear direction with a predetermined length; and an upper extension 36, which extends integrally from the upper end of the main body 32 in the front-rear direction with a predetermined length.

[0033] like Figure 3As shown, the lower protrusion 34 extends outward in a rear-to-rear direction, covering the insulating film 20 that covers the bottom wall 24 of the electrode body 22 from below. The insulating film 20 supports the bottom wall 24 of the electrode body 22 from below, and its lower surface contacts the inner surface of the bottom wall 14 of the housing 12. Similarly, the upper protrusion 36 extends outward in a rear-to-rear direction, covering the insulating film 20 that covers the top wall 26 of the electrode body 22 from above, and its upper surface contacts the inner surface of the top wall 16 of the housing 12.

[0034] In addition, such as Figure 5 As shown, the length of the insulating film 20 along the left-right direction is slightly shorter than the length of the electrode body 22 along the left-right direction (approximately 2 mm recessed inward from the outer end faces of the electrode body 22 in the left-right direction), and the length of the plate 30 along the left-right direction is slightly shorter than the length of the electrode body 22 along the left-right direction (approximately 12 mm recessed inward from the outer end faces of the electrode body 22 in the left-right direction). That is, the structure is such that the outer ends of the electrode body 22 covered by the insulating film 20 protrude outward by a predetermined length (approximately 10 mm) from the outer ends of the plate 30 in the left-right direction.

[0035] Moreover, such as Figure 6 As shown, the insulating films 20 on adjacent electrode bodies 22 located further outward in the left-right direction (long side direction) than the plate 30 are joined together by thermal fusion. More specifically, the upper and lower portions of the insulating films 20 on adjacent electrode bodies 22 located further outward in the left-right direction than the plate 30, and approximately 5 mm inward from the outer end of the insulating film 20 in the left-right direction, are respectively joined by thermal fusion to form welded portions Tw. Thus, a structure is created that suppresses or prevents the plate 30 from moving relative to the electrode bodies 22 covered by the insulating films 20 in the left-right direction (long side direction).

[0036] And, as Figure 3 , Figure 5 As shown, a heat-conducting sheet 38, formed of silicone resin material with a predetermined thickness (e.g., 2 mm), is attached to at least the outer surface of the bottom wall 14 of the housing 12, covering substantially the entire surface. The energy storage device 40 according to this embodiment is configured including an energy storage unit 10 and the heat-conducting sheet 38. Furthermore, in Figure 3 , Figure 5 In the text, the thickness of the insulating film 20 and the thickness of the heat-conducting sheet 38 are exaggerated.

[0037] The function of the energy storage unit 10 and energy storage device 40 in this embodiment, as described above, will now be explained.

[0038] As described above, two rectangular electrode bodies 22, viewed from the long side, are housed within the housing 12. Furthermore, an "I"-shaped plate 30, viewed from the long side, is housed within the housing 12, positioned between the electrode bodies 22. In other words, with the electrode bodies 22 arranged on both the front and rear sides of the plate 30, both the plate 30 and the electrode bodies 22 are housed within the housing 12.

[0039] Here, the lower surface of the lower protrusion 34 formed at the lower end of the main body 32 of the plate 30 contacts the inner surface of the bottom wall 14 of the housing 12, and the upper surface of the upper protrusion 36 formed at the upper end of the main body 32 of the plate 30 contacts the inner surface of the top wall 16 of the housing 12. Therefore, the bottom wall 14 and top wall 16 of the housing 12 can be reinforced from the inside by means of this plate 30.

[0040] Therefore, even during repeated charging and discharging of the energy storage unit 10, the front and rear side walls (ventral surfaces) 18 of its housing 12 expand and deform outward in the thickness direction, which can suppress the contraction deformation of the bottom wall 14 and top wall 16 of the housing 12 due to the expansion deformation force, which causes them to indent in the upward and downward direction.

[0041] Therefore, it is possible to suppress the decrease (peeling) of contact between the bottom wall 14 of the housing 12 and the heat-conducting fins 38 disposed on the outer surface of the bottom wall 14, and to suppress the decrease in cooling efficiency of the energy storage unit 10. That is, it is possible to improve the heat dissipation of the housing 12, especially the bottom wall 14 side, and to efficiently cool (dissipate heat) the energy storage unit 10. Moreover, it is possible to reduce the risk of fire caused by the high temperature of the energy storage unit 10, and to suppress the decrease in output of the energy storage unit 10 (deterioration of the lifespan of the energy storage unit 10) caused by the extension of charging time and the increase in resistance.

[0042] Furthermore, an insulating film 20 is provided on the bottom wall 24, top wall 26, and side wall 28 of each electrode body 22 that is housed in the housing 12, which extend along the long side. Therefore, even if the plate 30 is made of metal, short circuits caused by contact between each electrode body 22 and the plate 30 can be prevented, as well as short circuits caused by contact between each electrode body 22 and the housing 12.

[0043] Moreover, the insulating film 20 is extremely thinner than the heat-conducting sheet 38, thus it can suppress the reduction of the volumetric energy density of the electrode body 22, effectively insulate each electrode body 22 from the plate 30, and effectively insulate each electrode body 22 from the housing 12.

[0044] Furthermore, the length of the plate 30 along its long side is set to be shorter than the length of the insulating film 20 along its long side. Moreover, the insulating films 20 on adjacent electrode bodies 22 located further outward along the long side than the plate 30 are joined together by thermal fusion (welding portions Tw are formed at the upper and lower parts respectively). Therefore, movement of the plate 30 relative to each electrode body 22 along its long side can be suppressed or prevented. Thus, even if the plate 30 is made of metal, short circuits caused by contact between the outer ends of each electrode body 22 and the plate 30 along its long side can be prevented.

[0045] The energy storage unit 10 and energy storage device 40 of this embodiment have been described above with reference to the accompanying drawings. However, the energy storage unit 10 and energy storage device 40 of this embodiment are not limited to the drawings and can be appropriately modified without departing from the spirit of the present invention. For example, the heat-conducting sheet 38 may be attached to approximately the entire outer surface of the top wall 16 of the housing 12.

[0046] Furthermore, the length of the energy storage unit 10 in the left-right direction, the length (height) in the up-down direction, and the length (thickness) in the front-back direction are not limited to the length shown in the figure. Also, the extension lengths of the lower extension 34 and the upper extension 36 of the plate 30 are not limited to the lengths shown in the figure, and can extend longer than the lengths shown. Furthermore, the plate 30 is not limited to being made of metal.

[0047] Furthermore, the number of electrode bodies 22 is not limited to the two shown in the figure; for example, it can also be three. When three electrode bodies 22 are provided, two plates 30 are provided so that the plates 30 are positioned between each electrode body 22. Thus, multiple electrode bodies 22 and multiple plates 30 are provided inside the housing 12.

[0048] Symbol Explanation

[0049] 10-Energy storage unit, 12-House, 14-Bottom wall, 20-Insulating film, 22-Electrode body, 24-Bottom wall, 26-Top wall, 28-Side wall, 30-Plate (wall component), 38-Heat-conducting plate (heat-conducting component), 40-Energy storage device.

Claims

1. An energy storage unit, characterized in that, have: Multiple electrode bodies, which are rectangular in shape in a cross-sectional view viewed from the long side; A wall component, which is "I"-shaped in a cross-sectional view viewed from the long side and is located between the plurality of electrode bodies; and A housing that accommodates the electrode body and the wall components.

2. The energy storage unit according to claim 1, characterized in that, An insulating film is provided on the bottom wall, top wall, and side wall of the electrode body extending along the long side direction.

3. The energy storage unit according to claim 2, characterized in that, The length of the wall component along the long side is set to be shorter than the length of the insulating film along the long side. The insulating films on a plurality of adjacent electrode bodies located further outward along the long side than the wall component are bonded to each other.

4. An energy storage device, characterized in that, have: The energy storage unit according to any one of claims 1 to 3; and A heat-conducting component is disposed on the outer surface of the bottom wall of the housing, which extends along the long side.

Images