power storage device

Abstract

The energy storage device includes a first electrode body, a second electrode body, and a housing. The housing includes a first end plate and a second end plate, the second end plate having an exhaust valve. The first electrode body and the second electrode body are arranged such that a first winding axis and a second winding axis pass through the first end plate and the second end plate, respectively. The first electrode body has a first hollow portion. The second electrode body has a second hollow portion. When viewed from an axial top view, the exhaust valve is arranged away from at least one of the first hollow portion and the second hollow portion.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electrical storage device. BACKGROUND

[0002] Various electrical storage units have been proposed. For example, an electrical storage unit having a housing and an electrode body housed in the housing is disclosed in Japanese Patent Application Publication No. 2014-154292. An exhaust valve is formed in the housing. SUMMARY

[0003] The position of the exhaust valve disclosed in Japanese Patent Application Publication No. 2014-154292 is the electrode body housed in the electrical storage unit, and the positional relationship with the winding center of the winding body is not considered. In the case where the internal pressure in the housing rises due to gas generation from the electrode body, the pressure distribution in the housing is uneven. In particular, the winding center portion is likely to become a flow-through portion of the gas at the time of gas ejection. Therefore, the internal pressure of the housing applied to the vicinity of the winding center surface is likely to become high, and by providing the exhaust valve in this portion, the exhaust valve can be immediately opened at the time of the internal pressure rise in the housing. On the other hand, if the exhaust valve is disposed in a manner overlapping with a plurality of winding center portions, the exhaust gas is likely to be directly blown toward the exhaust valve in the housing, and when viewed from the pressure distribution of the entire housing, it is possible that the exhaust valve is opened before the internal pressure in the housing reaches a prescribed pressure.

[0004] The present disclosure provides an electrical storage device that suppresses the opening of an exhaust valve before the internal pressure of a housing provided in an electrical storage unit mounted on the electrical storage device reaches a prescribed pressure.

[0005] The energy storage device disclosed herein includes a first electrode body, a second electrode body, and a housing. The first electrode body includes a first electrode plate, a first separator, a second electrode plate, and a second separator. The first electrode body is formed to surround a first winding axis extending axially. The second electrode body is disposed adjacent to the first electrode body and includes a third electrode plate, a third separator, a fourth electrode plate, and a fourth separator. The second electrode body is formed to surround a second winding axis extending axially. The housing houses the first and second electrode bodies. The housing includes a first end plate and a second end plate, the second end plate having an exhaust valve. The first and second electrode bodies are arranged such that the first and second winding axes pass through the first and second end plates. The first electrode plate is located on the inner periphery side of the second electrode plate in a first radial direction intersecting the axial direction and centered on the first winding axis. The third electrode plate is located on the inner periphery side of the fourth electrode plate in a second radial direction intersecting the axial direction and centered on the second winding axis. The first electrode body includes a first winding end face and a second winding end face, the first winding end face being located on the side of the second end plate and the second winding end face being located on the side of the first end plate. A first hollow portion is formed in the first electrode body extending from the first winding end face to the second winding end face. The first hollow portion is defined by a first electrode sheet located at the innermost circumference in a first radial direction. The second electrode body includes a third winding end face and a fourth winding end face, the third winding end face being located on the side of the second end plate and the fourth winding end face being located on the side of the first end plate. A second hollow portion is formed in the second electrode body extending from the third winding end face to the fourth winding end face. The second hollow portion is defined by a third electrode sheet located at the innermost circumference in a second radial direction. When viewed from an axial top view, the exhaust valve, the first winding end face, and the third winding end face are arranged away from at least one of the first hollow portion and the second hollow portion.

[0006] In the energy storage device of the present disclosure, when viewed from an axial top view of the vent valve, the first winding end face and the third winding end face, the vent valve may be disposed between the first hollow portion and the second hollow portion.

[0007] In the energy storage device of this disclosure, the second end plate may also have inner and outer surfaces arranged axially. The outer surface may also be disposed away from the first and second electrode bodies relative to the inner surface. The outer surface has an outer edge portion that defines the outer edge of the outer surface. A first arcuate portion may also be formed at the side end of the first winding end face. A second arcuate portion may also be formed at the side end of the third winding end face. When the outer surface, the first winding end face, and the third winding end face are viewed from above in the axial direction, the outer edge portion, the first arcuate portion, and the second arcuate portion may also define a gap region on the outer surface. The exhaust valve may also be disposed at a position that at least partially overlaps with the gap region.

[0008] The energy storage device of this disclosure may also include a cooler. The second end plate may also have an opening. The cooler may also be axially not opposite to the opening. The exhaust valve may also be axially opposite to at least a portion of the opening.

[0009] In the energy storage device of this disclosure, the second end plate may also have an inner surface and an outer surface arranged axially, and a defined opposing region within the outer surface. The outer surface may also be disposed away from the first electrode and the second electrode relative to the inner surface. When viewed from an axial top view of the outer surface and the first winding end face, the opposing region may also be the region where the outer surface and the first winding end face overlap. The cooler may also be disposed axially opposite to the opposing region. The exhaust valve may also be disposed away from the opposing region.

[0010] In the energy storage device of the present disclosure, electrode terminals may also be provided on the first end plate.

[0011] In the energy storage device of this disclosure, the energy storage device is disposed below the bottom of the vehicle. The first end plate may also be disposed near the bottom relative to the second end plate.

[0012] According to the energy storage device disclosed herein, it is possible to prevent the vent valve from opening before the internal pressure of the housing of the energy storage unit mounted on the energy storage device reaches a specified pressure. Attached Figure Description

[0013] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and wherein: Figure 1 This is a schematic diagram showing a vehicle equipped with the energy storage device according to an embodiment of the present disclosure.

[0014] Figure 2 This is an exploded perspective view of the energy storage device in the embodiments of this disclosure.

[0015] Figure 3 This is a perspective view of the energy storage unit in an embodiment of this disclosure.

[0016] Figure 4 This is an exploded perspective view of the energy storage unit in an embodiment of this disclosure.

[0017] Figure 5 Viewed from the direction of the VV line arrow, containing Figure 3 A cross-sectional view obtained from the first electrode of the energy storage unit shown.

[0018] Figure 6 yes Figure 5 An enlarged view of the first hollow section shown.

[0019] Figure 7 It is observed along the direction of the arrow in line VII-VII that the container is located in Figure 3 A cross-sectional view obtained from the second electrode of the energy storage unit shown.

[0020] Figure 8 Observe from the direction of the arrow on line VIII-VIII Figure 1 The end view obtained from the energy storage device shown.

[0021] Figure 9 This is viewed from the position where the plate separates axially from the cooler side. Figure 8 The top view is obtained by examining the outer surface of the base plate of the energy storage unit shown.

[0022] Figure 10 This is a top view obtained from a modified example 1 of the base plate of the energy storage unit in the embodiment of this disclosure, viewed from a position where it is separated axially from the base plate towards the cooler side.

[0023] Figure 11 This is a top view obtained from a modified example 2 of the base plate of the energy storage unit in the embodiment of this disclosure, viewed from a position where it is separated axially from the base plate towards the cooler side.

[0024] Figure 12 This is a top view obtained by observing a modified example 3 of the energy storage unit in the embodiment of this disclosure from a position where it is separated axially from the base plate towards the cooler side.

[0025] Figure 13 This is a top view obtained from a position where the energy storage unit in the embodiment of this disclosure is separated from the base plate towards the cooler side in the axial direction. Detailed Implementation

[0026] Hereinafter, embodiments and variations of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same or equivalent parts are labeled with the same reference numerals, and their descriptions will not be repeated.

[0027] <Implementation Method>

[0028] Figure 1 This is a schematic side view of a vehicle equipped with the energy storage device of this embodiment. Furthermore, Figure 1 The vertical direction H shown represents the vertical direction of vehicle 1. Furthermore, the vertical direction H is the same direction as the axial direction A of the first winding axis α1 of the first electrode body 81, which will be described later. The width direction W represents the width direction of vehicle 1. The front-rear direction D represents the front-rear direction of vehicle 1.

[0029] Vehicle 1 includes a body 2 and an energy storage device 3. Vehicle 1 may include, for example, a PHEV (Plug-in Hybrid Electric Vehicle), a BEV (Battery Electric Vehicle), or an FCEV (Fuel Cell Electric Vehicle). The energy storage device 3 is located below the bottom 2a of the body 2.

[0030] Figure 2 This is an exploded perspective view of the energy storage device in this embodiment. The energy storage device 3 includes a housing 4, an energy storage stack 15, and... Figure 8 Cooler 13 is shown.

[0031] The housing 4 includes an upper cover 5 and a lower housing 6. The housing 4 forms a receiving space V defined by the upper cover 5 and the lower housing 6.

[0032] The upper cover 5 is formed to cover the lower shell 6, which is formed by opening upwards.

[0033] The lower housing 6 includes a bottom wall 7 and a wall portion 8. The bottom wall 7 supports the energy storage stack 15 in the vertical direction H. An opening 7a, described later, is formed in the bottom wall 7 (see reference). Figure 8 The opening 7a is positioned opposite the exhaust valve 21ab, which will be described later.

[0034] The wall portion 8 is formed to rise upward from the bottom wall 7 in the vertical direction H. The wall portion 8 has a peripheral wall 9 and a reinforcing portion 12. The peripheral wall 9 is formed to extend in a frame shape and is formed to extend upward from the outer periphery of the bottom wall 7 in the vertical direction H. The peripheral wall 9 has a first side wall 10 and a second side wall 11. The first side wall 10 and the second side wall 11 are formed to extend in the front-rear direction D and are arranged at intervals in the width direction W.

[0035] The reinforcing part 12 is formed to extend along the front-rear direction D. The reinforcing part 12 is arranged in such a way that it passes through the center of the first sidewall 10 and the second sidewall 11 in the width direction W.

[0036] The energy storage stack 15 is housed in the receiving space V and disposed on the upper surface of the bottom wall 7. The energy storage stack 15 is formed by a plurality of energy storage units 100. The plurality of energy storage units 100 are arranged in the front-rear direction D. The energy storage units 100 are formed in a cuboid shape, and the cuboid shape is formed as a strip in the width direction W.

[0037] Figure 3 A three-dimensional view showing the energy storage unit 100. (e.g.) Figure 3As shown, the energy storage unit 100 in this embodiment is a so-called square battery. The energy storage unit 100 can be configured as a rechargeable battery, such as a lithium-ion battery or a nickel-metal hydride battery.

[0038] Figure 4 This is an exploded perspective view of a battery according to an embodiment of this disclosure. (As shown...) Figure 4 As shown, the energy storage unit 100 includes a housing 20, an insulating member 70, and multiple electrode bodies 80.

[0039] The housing 20 is conductive. The housing 20 is made of a metal such as aluminum. The housing 20 houses a plurality of electrode bodies 80. The housing 20 also houses an electrolyte (not shown). The housing 20 includes a housing body 21 and a top plate 22.

[0040] The main body 21 of the housing includes a base plate 21a and a peripheral wall 21b that rises from the base plate 21a. The base plate 21a is joined to the peripheral wall 21b at its outer peripheral edge.

[0041] The base plate 21a includes a base body 21aa and an exhaust valve 21ab. Furthermore, the base body 21aa is an example of the "second end plate" of this disclosure.

[0042] An exhaust valve 21ab is formed on the bottom body 21aa. The exhaust valve 21ab is a known type of exhaust valve. For example, the exhaust valve 21ab has a general portion that is machined to be thinner than the bottom body 21aa. A rupture groove is formed in the general portion of the exhaust valve 21ab. By appropriately designing this groove, the exhaust valve 21ab can be selectively ruptured by a small increase in pressure inside the housing 20. The groove is formed, for example, by a die and a punch. When viewed from above in the axial direction A, the groove is elliptical or straight.

[0043] The peripheral wall 21b rises from the base body 21aa. An opening is formed at the upper end of the peripheral wall 21b. The peripheral wall 21b has a roughly rectangular shape when viewed from the vertical direction H. The peripheral wall 21b and the base plate 21a are arranged in the vertical direction H. The peripheral wall 21b is made of a metal such as aluminum.

[0044] The top plate 22 includes a top plate body 22a, a sealing bolt 22b, a bolt cover 22c, an insulating cover 22d, and an electrode terminal 22e. Furthermore, the top plate body 22a is an example of the "first end plate" of this disclosure.

[0045] The top plate body 22a is joined to the peripheral wall 21b by welding or the like, thereby closing the opening of the peripheral wall 21b. Electrode terminals 22e are provided on the top plate body 22a. A first connecting hole 22aa, a second connecting hole 22ab, and an electrolyte injection hole 22ac are formed on the top plate body 22a. The electrolyte injection hole 22ac is a through hole for injecting electrolyte into the housing body 21 during the manufacturing process of the energy storage unit 100. The top plate body 22a is positioned near the bottom 2a of the vehicle body 2 relative to the bottom body 21aa.

[0046] The sealing plug 22b seals the injection hole 22ac. The plug cover 22c covers the injection hole 22ac and the sealing plug 22b. The insulating cover 22d covers the injection hole 22ac, the sealing plug 22b, and the plug cover 22c.

[0047] The electrode terminal 22e has a first external terminal 30A, a second external terminal 30B, a first connecting member 40A, a second connecting member 40B, a first sealing ring 50A, a second sealing ring 50B, a first terminal support portion 60A, and a second terminal support portion 60B.

[0048] The first external terminal 30A and the second external terminal 30B are provided in the energy storage unit 100 in an exposed manner.

[0049] The first connecting structural member 40A and the second connecting structural member 40B are conductive. At least a portion of the first connecting structural member 40A and the second connecting structural member 40B is disposed inside the housing 20.

[0050] The first external terminal 30A or the first connecting member 40A is inserted into the first connecting hole 22aa. The first external terminal 30A and the first connecting member 40A are engaged with each other. The first connecting member 40A is electrically connected to the electrode body 80. Thus, the first external terminal 30A is electrically connected to the electrode body 80.

[0051] The second external terminal 30B or the second connecting member 40B is inserted into the second connecting hole 22ab. The second external terminal 30B and the second connecting member 40B are engaged with each other. The second connecting member 40B is electrically connected to the electrode body 80. Thus, the second external terminal 30B is electrically connected to the electrode body 80.

[0052] A first sealing ring 50A is disposed along the first connecting hole 22aa. The first sealing ring 50A is disposed in the gap between the top plate body 22a and the first external terminal 30A, sealing the gap. A second sealing ring 50B is disposed along the second connecting hole 22ab. The second sealing ring 50B is disposed in the gap between the top plate body 22a and the second external terminal 30B, sealing the gap. The first sealing ring 50A and the second sealing ring 50B are electrically insulating.

[0053] The first terminal support portion 60A is secured to the top plate body 22a. The first terminal support portion 60A supports the first external terminal 30A from its outer periphery. The first terminal support portion 60A includes a first locking ring 61A and a first covering ring 62A. The first locking ring 61A extends annularly around the first connecting hole 22aa and is directly secured to the top plate body 22a. The first covering ring 62A covers the first locking ring 61A. The first locking ring 61A supports the first external terminal 30A via the first covering ring 62A. The first covering ring 62A is made of an electrically insulating resin component.

[0054] The second terminal support portion 60B is secured to the top plate body 22a. The second terminal support portion 60B supports the second external terminal 30B from its outer periphery. The second terminal support portion 60B includes a second locking ring 61B and a second covering ring 62B. The second locking ring 61B extends annularly around the second connecting hole 22ab and is directly secured to the top plate body 22a. The second covering ring 62B covers the second locking ring 61B. The second locking ring 61B supports the second external terminal 30B via the second covering ring 62B. The second covering ring 62B is made of an electrically insulating resin component.

[0055] The insulating member 70 is electrically insulating. The insulating member 70 is disposed between the electrode body 80 and the housing 20. The insulating member 70 electrically insulates the electrode body 80 and the housing 20 from each other. The insulating member 70 includes an insulating bracket 71, a peripheral insulating portion 72, and a bottom insulating portion 73.

[0056] An insulating bracket 71 is disposed between the electrode body 80 and the top plate body 22a. The insulating bracket 71 has high rigidity and contacts both the electrode body 80 and the top plate body 22a. Thus, the electrode body 80 is fixed to the housing 20 in the vertical direction H. A peripheral insulating portion 72 is disposed between the electrode body 80 and the peripheral wall 21b. The peripheral insulating portion 72 is composed of a film-like component. A bottom insulating portion 73 is disposed between the electrode body 80 and the bottom plate 21a. The bottom insulating portion 73 is composed of a film-like component. In this embodiment, the bottom insulating portion 73 is bonded to the electrode body 80.

[0057] The electrode body 80 is a so-called wound electrode body. The electrode body 80 typically has a first electrode body 81 and a second electrode body 91. The first electrode body 81 and the second electrode body 91 are arranged adjacent to each other in the front-rear direction D. The peripheral insulating portion 72 may also integrally cover the electrode body 80 in a manner in which the first electrode body 81 and the second electrode body 91 are fixed to each other.

[0058] The first electrode body 81 has a first sheet 151A and a second sheet 151B. The second electrode body 91 has a first sheet 152A and a second sheet 152B. The first sheet 151A electrically connects the first electrode sheet 82 (described later) of the first electrode body 81 to the first connecting member 40A. The second sheet 151B electrically connects the second electrode sheet 83 (described later) of the first electrode body 81 to the second connecting member 40B. The first sheet 152A electrically connects the third electrode sheet 92 (described later) of the second electrode body 91 to the first connecting member 40A. The second sheet 152B electrically connects the fourth electrode sheet 93 (described later) of the second electrode body 91 to the second connecting member 40B.

[0059] First sheets 151A and 152A are arranged in a front-rear direction D. The first sheets 151A and 152A are joined together, for example, by ultrasonic welding. The first sheets 151A and 152A are also joined to the first connecting member 40A, for example, by ultrasonic welding. Second sheets 151B and 152B are arranged in a front-rear direction D. The second sheets 151B and 152B are joined together, for example, by ultrasonic welding. The second sheets 151B and 152B are also joined to the second connecting member 40B, for example, by ultrasonic welding.

[0060] The following uses Figure 5 The details of the first electrode body 81 are explained below. Figure 5 Viewed from the direction of the VV line arrow, containing Figure 3 The end face view of the first electrode body 81 of the energy storage unit 100 shown.

[0061] The first electrode body 81 includes a first electrode sheet 82, a second electrode sheet 83, a first separator 84A, a second separator 84B, and a strip member 85. The first electrode sheet 82, the second electrode sheet 83, the first separator 84A, and the second separator 84B have a sheet-like shape. The first electrode sheet 82, the second electrode sheet 83, the first separator 84A, and the second separator 84B are collectively referred to as a sheet group. The first electrode body 81 is formed by winding the first electrode sheet 82 and the second electrode sheet 83 around a first winding axis α1 via the first separator 84A and the second separator 84B. That is, the first electrode body 81 is a so-called wound electrode body. Here, the first winding axis α1 is the axis of the first electrode body 81 extending along the axial direction A. In this embodiment, the axial direction A is the same direction as the vertical direction H. The first electrode body 81 is formed such that it surrounds the first winding axis α1 in a first radial direction R1 intersecting the axial direction A and centered on the first winding axis α1, starting from the inner circumference side, in the order of first separator 84A, first electrode plate 82, second separator 84B, and second electrode plate 83. Thus, a first hollow portion S1 centered on the first winding axis α1 is formed in the first electrode body 81. More specifically, in this embodiment, the first electrode plate 82 is located on the inner circumference side of the first radial direction R1 compared to the second electrode plate 83, such as... Figure 6 As shown, the first hollow portion S1 is defined by the first electrode sheet 82 located on the innermost circumference in the first radial direction R1.

[0062] The first electrode plate 82 includes a first current collector 82A and a first active material layer 82B. The second electrode plate 83 includes a second current collector 83A and a second active material layer 83B. In this embodiment, the first electrode plate 82 is the positive electrode and the second electrode plate 83 is the negative electrode. However, it is also possible for the first electrode plate 82 to be the negative electrode and the second electrode plate 83 to be the positive electrode.

[0063] The first separator 84A and the second separator 84B enable the exchange of ions between the first electrode plate 82 and the second electrode plate 83, and separate the first electrode plate 82 and the second electrode plate 83. The ions are, for example, lithium ions. The first separator 84A and the second separator 84B are electrically insulating. The first separator 84A is located on the innermost circumference in the first radial direction R1. On the other hand, the second separator 84B is located on the outermost circumference in the first radial direction R1. The outer circumferential edge of the second separator 84B in the first radial direction R1 is fixed by a strip member 85 disposed on the outer circumferential surface of the second separator 84B.

[0064] The following uses Figure 7 The details of the second electrode 91 will be described. Furthermore, the first electrode 81 and the second electrode 91 have substantially the same structure. Figure 7It is observed along the direction of the arrow in line VII-VII that the container is located in Figure 3 A cross-sectional view of the second electrode body 91 of the energy storage unit 100 shown.

[0065] The second electrode body 91 includes a third electrode sheet 92, a fourth electrode sheet 93, a third separator 94A, a fourth separator 94B, and a strip member 95. The third electrode sheet 92, the fourth electrode sheet 93, the third separator 94A, and the fourth separator 94B have a sheet-like shape. The third electrode sheet 92, the fourth electrode sheet 93, the third separator 94A, and the fourth separator 94B together are referred to as a sheet assembly. The second electrode body 91 is formed by winding the third electrode sheet 92 and the fourth electrode sheet 93 around a second winding axis α2 via the third separator 94A and the fourth separator 94B. That is, the second electrode body 91 is a so-called wound electrode body. Here, the second winding axis α2 is the axis of the second electrode body 91 extending along the axial direction A. In this embodiment, the axial direction A is the same direction as the vertical direction H. The second electrode body 91 is formed such that it surrounds the second winding axis α2 in a second radial direction R2, intersecting the axial direction A and centered on the second winding axis α2, starting from the inner circumference side, in the order of third separator 94A, third electrode plate 92, fourth separator 94B, and fourth electrode plate 93. Thus, a second hollow portion S2 centered on the second winding axis α2 is formed in the second electrode body 91. More specifically, in this embodiment, the third electrode plate 92 is located on the innermost circumference side of the second radial direction R2 compared to the fourth electrode plate 93, and the second hollow portion S2 is defined by the third electrode plate 92 located on the innermost circumference side of the second radial direction R2.

[0066] The third electrode 92 includes a third current collector 92A and a third active material layer 92B. The fourth electrode 93 includes a fourth current collector 93A and a fourth active material layer 93B.

[0067] The third separator 94A and the fourth separator 94B enable the exchange of ions between the third electrode plate 92 and the fourth electrode plate 93, and separate the third electrode plate 92 and the fourth electrode plate 93. The ions mentioned above are, for example, lithium ions. The third separator 94A and the fourth separator 94B are electrically insulating. The third separator 94A is located on the innermost circumference in the second radial direction R2. On the other hand, the fourth separator 94B is located on the outermost circumference in the second radial direction R2. The outer circumferential edge of the fourth separator 94B in the second radial direction R2 is fixed by a strip member 95 disposed on the outer circumferential surface of the fourth separator 94B.

[0068] Figure 8 Observe from the direction of the arrow on line VIII-VIII Figure 1 The end view obtained from the energy storage device shown.

[0069] Inside the housing 20, a first electrode body 81 and a second electrode body 91 are arranged with the first winding axis α1 and the second winding axis α2 passing through the top plate 22 and the bottom plate 21a.

[0070] The first electrode body 81 has a first winding end face 86 and a second winding end face 87. The first winding end face 86 and the second winding end face 87 are arranged spaced apart in the axial direction A. The first winding end face 86 is located on the bottom plate 21a side. The second winding end face 87 is located on the top plate 22 side. Here, the first hollow portion S1 is formed to extend from the first winding end face 86 to the second winding end face 87.

[0071] The second electrode body 91 has a third winding end face 96 and a fourth winding end face 97. The third winding end face 96 and the fourth winding end face 97 are arranged spaced apart in the axial direction A. The third winding end face 96 is located on the bottom plate 21a side. The fourth winding end face 97 is located on the top plate 22 side. Here, the second hollow portion S2 is formed to extend from the third winding end face 96 to the fourth winding end face 97.

[0072] The base plate 21a of the housing body 21 has an inner surface 21ac and an outer surface 21ad. The inner surface 21ac and the outer surface 21ad are arranged spaced apart in the axial direction A. The inner surface 21ac is located on the electrode body 80 side relative to the outer surface 21ad. The outer surface 21ad is located on the bottom wall 7 side relative to the inner surface 21ac. The outer surface 21ad is arranged away from the first electrode body 81 and the second electrode body 91 relative to the inner surface 21ac. The outer surface 21ad has a relative region 21ae. The relative region 21ae is a region defined within the outer surface 21ad, and is the region where the outer surface 21ad and the first winding end face 86 overlap when viewed from the axial direction A.

[0073] An opening 7a is formed in the bottom wall 7 of the housing 4. The opening 7a is positioned opposite the exhaust valve 21ab. The energy storage device 3 includes a cooler 13. The cooler 13 is disposed on the bottom wall 7. In the vertical direction H, the cooler 13 is positioned relative to the bottom wall 7 on the side opposite to the energy storage unit 100. More specifically, the cooler 13 is positioned in the axial direction A, sandwiching the bottom wall 7 in the middle and opposite to the opposing region 21ae. Furthermore, the cooler 13 is positioned opposite to the opposing region 21ae, meaning that when viewed from the axial direction A, at least a portion of the cooler 13 overlaps with the opposing region 21ae. In this embodiment, the cooler 13 cools the plurality of energy storage units 100 of the energy storage stack 15. A cooling medium (oil, etc.) flows within the cooler 13.

[0074] The housing 4 also has a common panel 14. The common panel 14 is located on the side opposite to the energy storage unit 100, with the bottom wall 7 as a reference, in the vertical direction H. The common panel 14 is positioned on the bottom wall 7, sandwiching the cooler 13 in the middle. The common panel 14 serves to protect the lower housing 6. The common panel 14 can also be formed as a flat plate.

[0075] Figure 9 This is viewed from the position where the plate separates axially from the cooler side. Figure 8 The top view is obtained by examining the outer surface of the base plate of the energy storage unit shown.

[0076] The first winding end face 86 of the first electrode body 81 has a pair of first arcuate portions 86a and a pair of first straight portions 86b. The pair of first arcuate portions 86a and the pair of first straight portions 86b form the outer edge of the first winding end face 86. The pair of first arcuate portions 86a are respectively located at the side ends of the first winding end face 86 and are arranged at intervals in the width direction W. The pair of first straight portions 86b are respectively arranged at intervals in the front-rear direction D. One of the pair of first straight portions 86b connects one end of the pair of first arcuate portions 86a to the other end of the pair of first arcuate portions 86a. The other of the pair of first straight portions 86b connects the other end of one of the pair of first arcuate portions 86a to the other end of the pair of first arcuate portions 86a.

[0077] The third winding end face 96 of the second electrode body 91 has a pair of second arcuate portions 96a and a pair of second straight portions 96b. The pair of second arcuate portions 96a and the pair of second straight portions 96b form the outer edge of the third winding end face 96. The pair of second arcuate portions 96a are respectively located at the side ends of the third winding end face 96 and are arranged at intervals in the width direction W. The pair of second straight portions 96b are respectively arranged at intervals in the front-rear direction D. One end of one pair of second straight portions 96b connects to the end of the other pair of second arcuate portions 96a. The other end of one pair of second straight portions 96b connects to the other end of the other pair of second arcuate portions 96a.

[0078] The outer surface 21ad of the base plate 21a has an outer edge portion 21af that defines the outer edge of the outer surface 21ad. When the outer surface 21ad, the first winding end face 86 and the third winding end face 96 are viewed from the axial direction A, the area on the outer surface 21ad defined by the outer edge portion 21af, the first arc portion 86a and the second arc portion 96a is called the gap region G.

[0079] The first electrode body 81 has a first hollow portion S1 and a first winding end face 86 formed around a first winding axis α1. The second electrode body 91 has a second hollow portion S2 and a third winding end face 96 formed around a second winding axis α2. An exhaust valve 21ab is provided on the bottom plate 21a of the housing 20 that houses the first electrode body 81. A relative area 21ae is defined on the outer surface 21ad of the bottom plate 21a.

[0080] When viewed from axial direction A, the exhaust valve 21ab, the first winding end face 86, and the third winding end face 96 are arranged away from the first hollow portion S1. More specifically, the exhaust valve 21ab is arranged to avoid the opposing region 21ae. Here, the exhaust valve 21ab being arranged away from the first hollow portion S1 means that, when viewed from axial direction A, the center portion of the exhaust valve 21ab does not overlap with the first hollow portion S1. Furthermore, the exhaust valve 21ab being arranged to avoid the opposing region 21ae means that, when viewed from axial direction A, the center portion of the exhaust valve 21ab does not overlap with the opposing region 21ae.

[0081] Alternatively, the exhaust valve 21ab can be configured such that at least one of the first hollow portion S1 and the second hollow portion S2 does not overlap with a portion of the exhaust valve 21ab.

[0082] Normally, gas is generated from the electrode body 80 due to the use of the energy storage unit 100. When the internal pressure within the housing 20 rises due to the gas generated from the electrode body 80, the pressure distribution within the housing 20 becomes uneven. The first hollow portion S1 and the second hollow portion S2 easily become gas flow passages when gas is ejected. Therefore, the internal pressure applied to the housing 20 facing the first hollow portion S1 and the second hollow portion S2 tends to become high.

[0083] Here, the case where the exhaust valve is arranged to overlap with multiple winding center portions (the first hollow portion S1 and the second hollow portion S2 in this embodiment) will be described. In this case, when gas is generated from the first electrode body 81 and the second electrode body 91, the gas ejected from the first hollow portion S1 and the second hollow portion S2 is also sprayed onto the exhaust valve. As a result, the exhaust valve may open before the internal pressure inside the housing 20 reaches a predetermined pressure.

[0084] On the other hand, in the energy storage device 3 of this embodiment, the exhaust valve 21ab is arranged away from the first hollow portion S1. With this structure, even when gas is generated from the first electrode body 81 and the second electrode body 91, it is possible to prevent gas from the first hollow portion S1 from being blown onto the exhaust valve 21ab. Therefore, it is possible to prevent the exhaust valve 21ab from opening before the internal pressure within the housing reaches a predetermined internal pressure.

[0085] With this structure, the exhaust valve 21ab can be prevented from opening before the internal pressure of the housing 20 of the energy storage unit 100 mounted on the energy storage device 3 reaches a specified pressure.

[0086] Furthermore, an example has been shown where the exhaust valve 21ab is configured away from the first hollow portion S1, but the embodiments of this disclosure are not limited to this. For example, the exhaust valve 21ab may be configured away from at least one of the first hollow portion S1 and the second hollow portion S2. For example, if the exhaust valve is configured to overlap with both the first hollow portion S1 and the second hollow portion S2, gas from both the first hollow portion S1 and the second hollow portion S2 may be blown into the exhaust valve 21ab. On the other hand, if the exhaust valve 21ab is configured away from at least one of the first hollow portion S1 and the second hollow portion S2, gas from both the first hollow portion S1 and the second hollow portion S2 can be prevented from being blown into the exhaust valve 21ab. Furthermore, it is possible to prevent the exhaust valve 21ab from opening before the internal pressure of the housing 20 of the energy storage unit 100 mounted on the energy storage device 3 reaches a predetermined pressure.

[0087] In this embodiment, the cooler 13 of the energy storage device 3 is positioned opposite to the opposing region 21ae. Furthermore, the exhaust valve 21ab is positioned away from the opposing region 21ae. The opening 7a is positioned opposite to the exhaust valve 21ab. With this structure, it is possible to prevent the opening 7a from being closed by the cooler 13. Moreover, it is possible to prevent the outlet of gas discharged from the exhaust valve 21ab from being closed. Furthermore, the exhaust valve 21ab only needs to be opposite to at least a portion of the opening 7a.

[0088] Furthermore, an example is shown where the cooler 13 is positioned opposite the opposing region 21ae, but embodiments of this disclosure are not limited thereto. For example, the cooler 13 may not be opposite the opening 7a in the axial direction A, and the exhaust valve 21ab may be opposite a portion of the opening 7a in the axial direction A. With such a configuration, it is possible to prevent the opening 7a from being closed by the cooler 13. Moreover, it is possible to prevent the outlet of gas discharged from the exhaust valve 21ab from being closed.

[0089] In this embodiment, an electrode terminal 22e is provided on the top plate body 22a, and an exhaust valve 21ab is formed on the bottom body 21aa. With this structure, when gas is ejected from the exhaust valve 21ab, short circuits of the electrode terminal 22e due to debris contained in the gas can be suppressed.

[0090] In this embodiment, the energy storage device 3 is disposed below the bottom 2a of the vehicle 1, and the top plate main body 22a is disposed near the bottom 2a relative to the bottom main body 21aa. Furthermore, the exhaust valve 21ab is formed on the bottom main body 21aa. With this structure, when gas is ejected from the exhaust valve 21ab, it is possible to prevent gas from flowing into the interior of the vehicle 1.

[0091] <Variation Example 1>

[0092] In this embodiment, an example is shown where the exhaust valve 21ab is configured away from at least one of the first hollow portion S1 and the second hollow portion S2, but embodiments of this disclosure are not limited thereto. For example, as Figure 10 As shown, when viewed from axial direction A, the exhaust valve 21ab, the first winding end face 86, and the third winding end face 96 can also be disposed between the first hollow portion S1 and the second hollow portion S2. Furthermore, the exhaust valve 21ab can also be disposed in a manner that does not overlap with either the first hollow portion S1 or the second hollow portion S2. Additionally, Figure 10 This is viewed from the position where the plate separates axially from the cooler side. Figure 8 The top view is obtained by examining the outer surface of the base plate of the energy storage unit shown.

[0093] For example, when the exhaust valve 21ab is configured away from at least one of the first hollow portion S1 and the second hollow portion S2, gas from at least one of the first hollow portion S1 and the second hollow portion S2 is sprayed onto the exhaust valve 21ab, thereby opening the exhaust valve 21ab. A portion of the electrode body 80 within the housing 20 may then be discharged from the exhaust valve 21ab to the outside of the housing 20 along with the violently expelled gas. For example, in a wound electrode body, i.e., a first electrode body 81, formed by winding a sheet assembly, one end of the sheet assembly forming the first electrode body 81 faces the first hollow portion S1. The winding of the first electrode body 81 is unwound by the gas sprayed from the exhaust valve 21ab through the first hollow portion S1, and a portion of the first electrode body 81 may be discharged from the exhaust valve 21ab. If a portion of the electrode body 80 comes into contact with external gas, the compound constituting the electrode body reacts with the air, potentially generating high temperatures. On the other hand, if the exhaust valve 21ab is positioned between the first hollow portion S1 and the second hollow portion S2, it can prevent gas from the first hollow portion S1 or the second hollow portion S2 from being directly sprayed onto the exhaust valve 21ab. As a result, even if the exhaust valve 21ab cracks, it can prevent a portion of the electrode body 80 from being discharged to the outside by being attracted by the ejected gas.

[0094] <Variation Example 2>

[0095] In this embodiment, an example is shown where the exhaust valve 21ab is configured away from at least one of the first hollow portion S1 and the second hollow portion S2, but embodiments of this disclosure are not limited thereto. For example, as Figure 11 As shown, the exhaust valve 21ab can also be configured in a position that at least partially overlaps with the gap region G. Furthermore, Figure 11 This is viewed from the position where the plate separates axially from the cooler side. Figure 8 The top view is obtained by examining the outer surface of the base plate of the energy storage unit shown.

[0096] By arranging the exhaust valve 21ab so that it overlaps with the gap region G, the extent of overlap between the exhaust valve 21ab and the electrode body 80 can be reduced. As a result, when the exhaust valve 21ab cracks and gas inside the housing 20 is ejected to the outside, for example, compared to the case where the exhaust valve 21ab is arranged to overlap with the electrode body 80, the ejection of the first electrode sheet 82, etc., forming the first electrode body 81, to the outside can be suppressed.

[0097] <Variation Example 3>

[0098] In this embodiment, an example is shown where the electrode body 80 has a first electrode body 81 and a second electrode body 91, and the first electrode body 81 and the second electrode body 91 are arranged adjacent to each other in the front-rear direction D. However, the embodiments of this disclosure are not limited to this. For example, the energy storage unit may also have more than three electrode bodies.

[0099] use Figure 12 A modified example 3 of the energy storage unit 100, namely an energy storage unit 101 having three or more electrode bodies 80, will be described. Figure 12 This is a top view obtained by observing a modified example 3 of the energy storage unit in the embodiment of this disclosure from a position where it is separated axially from the base plate towards the cooler side.

[0100] The energy storage unit 101 has multiple electrode bodies 80, including a first electrode body 81, a second electrode body 91, a third electrode body 111, and a fourth electrode body 112. The third electrode body 111 and the fourth electrode body 112 each have a structure substantially the same as the first electrode body 81. Furthermore, the third electrode body 111 is formed by winding an electrode body and a separator around a third winding axis α3 extending along the axial direction A. A third hollow portion S3 centered on the third winding axis α3 is formed in the third electrode body 111. Similarly, the fourth electrode body 112 is formed by winding an electrode body and a separator around a fourth winding axis α4 extending along the axial direction A. A fourth hollow portion S4 centered on the fourth winding axis α4 is formed in the fourth electrode body 112.

[0101] In the energy storage unit 101 with such a structure, the exhaust valve 21ab can be configured in a manner that is away from at least one of the first hollow part S1, the second hollow part S2, the third hollow part S3 and the fourth hollow part S4.

[0102] <Variation Example 4>

[0103] In the energy storage unit 101 shown in Modification 3, an example is shown where the exhaust valve 21ab is configured away from at least one of the first hollow portion S1, the second hollow portion S2, the third hollow portion S3, and the fourth hollow portion S4, but this disclosure is not limited thereto. Figure 13 As shown, the exhaust valve 21ab can also be configured in a manner that is completely away from the first hollow section S1, the second hollow section S2, the third hollow section S3 and the fourth hollow section S4.

[0104] The embodiments of this disclosure have been described above, but it should be considered that the embodiments disclosed herein are illustrative rather than restrictive in all respects. The scope of the technology shown in this disclosure is defined by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. An energy storage device, wherein, The energy storage device includes: The first electrode body includes a first electrode sheet, a first separator, a second electrode sheet, and a second separator, formed in such a way as to surround the periphery of a first winding axis extending along the axial direction; The second electrode body is arranged adjacent to the first electrode body and includes a third electrode sheet, a third spacer, a fourth electrode sheet, and a fourth spacer, formed to surround the periphery of a second winding axis extending along the axial direction; and A housing is provided to house the first electrode and the second electrode. The housing includes a first end plate and a second end plate, the second end plate having an exhaust valve. The first electrode and the second electrode are configured such that the first winding axis and the second winding axis pass through the first end plate and the second end plate, respectively. The first electrode sheet is located on the inner periphery side of the second electrode sheet in a first radial direction that intersects the axial direction and is centered on the first winding axis. The third electrode plate is located on the inner periphery side of the fourth electrode plate in a second radial direction that intersects the axial direction and is centered on the second winding axis. The first electrode body includes a first winding end face and a second winding end face, wherein the first winding end face is located on the side of the second end plate, and the second winding end face is located on the side of the first end plate. A first hollow portion is formed in the first electrode body, extending from the first winding end face to the second winding end face. The first hollow portion is defined by the first electrode sheet located on the innermost circumference in the first radial direction. The second electrode body includes a third winding end face and a fourth winding end face, wherein the third winding end face is located on the side of the second end plate, and the fourth winding end face is located on the side of the first end plate. A second hollow portion is formed in the second electrode body, extending from the third winding end face to the fourth winding end face. The second hollow portion is defined by the third electrode plate located on the innermost circumferential side in the second radial direction. When viewed from above along the axial direction, the exhaust valve, the first winding end face, and the third winding end face are arranged away from at least one of the first hollow portion and the second hollow portion.

2. The energy storage device according to claim 1, wherein, When viewed from above along the axial direction, the exhaust valve, the first winding end face, and the third winding end face are arranged between the first hollow portion and the second hollow portion.

3. The energy storage device according to claim 1, wherein, The second end plate has inner and outer surfaces arranged in the axial direction. The outer surface is disposed away from the first electrode and the second electrode relative to the inner surface. The outer surface has an outer edge portion that defines the outer edge of the outer surface. A first arcuate portion is formed at the side end of the first winding end face. A second arcuate portion is formed at the side end of the third winding end face. When viewed from above along the axial direction, the outer surface, the first winding end face, and the third winding end face have defined gap areas on the outer surface, including the outer edge, the first arcuate portion, and the second arcuate portion. The exhaust valve is positioned at a location that overlaps with at least a portion of the gap region.

4. The energy storage device according to claim 1, wherein, The energy storage device also includes a cooler. The second end plate has an opening. The cooler is not opposite the opening in the axial direction. The exhaust valve is opposite at least a portion of the opening in the axial direction.

5. The energy storage device according to claim 4, wherein, The second end plate has an inner surface and an outer surface arranged in the axial direction, and a defined relative area within the outer surface. The outer surface is disposed away from the first electrode and the second electrode relative to the inner surface. When viewed from above along the axial direction, the outer surface and the first winding end face are considered to be in a region where the outer surface and the first winding end face overlap. The cooler is positioned axially opposite the relative region. The exhaust valve is configured to avoid the relative area.

6. The energy storage device according to claim 1, wherein, Electrode terminals are provided on the first end plate.

7. The energy storage device according to claim 1, wherein, The energy storage device is disposed below the bottom of the vehicle, and the first end plate is disposed near the bottom relative to the second end plate.

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