power storage unit

Abstract

The present application relates to an electricity storage unit, comprising: a conductive core portion; a wound electrode body including a first electrode sheet and a second electrode sheet; and a first connecting member and a second connecting member. The core portion has a rectangular parallelepiped shape. A first electrode of the core portion is connected to the first electrode sheet and the first connecting member, respectively. A second electrode of the core portion is connected to the second electrode sheet and the second connecting member, respectively.

Description

Technical Field

[0001] This disclosure relates to energy storage units. Background Technology

[0002] Japanese Patent Application Publication No. 2023-516411 discloses a wound-type electrode assembly. The wound-type electrode assembly is formed by winding a positive electrode plate, a negative electrode plate, and a separator. Positive electrode tabs and negative electrode tabs are respectively provided on the positive electrode plate and the negative electrode plate. Summary of the Invention

[0003] In Japanese Patent Application Publication No. 2023-516411, as described above, a positive electrode tab and a negative electrode tab are respectively provided on the positive electrode plate (electrode sheet) and the negative electrode plate (electrode sheet). Considering the possibility that the provision of positive and negative electrode tabs would complicate the structure of the electrode assembly (wound electrode body).

[0004] This disclosure is made to solve the above-mentioned problems, and its purpose is to provide an energy storage unit that simplifies the construction of the wound electrode body.

[0005] One aspect of the energy storage unit disclosed herein includes: a conductive core portion; a wound electrode body including electrode sheets wound around the core portion; and a current collector disposed opposite to the wound electrode body in an axial direction extending from the core portion. The core portion has a cuboid shape and is connected to the electrode sheets and the current collector respectively. Furthermore, the cuboid shape also includes a cubic shape.

[0006] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description in connection with the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0007] Figure 1 This is a perspective view showing the configuration of the energy storage device and the frame members according to the first embodiment.

[0008] Figure 2 This is a perspective view showing the configuration of the energy storage unit according to the first embodiment.

[0009] Figure 3 This is an exploded perspective view showing the configuration of the energy storage unit according to the first embodiment.

[0010] Figure 4 This is a cross-sectional view of the wound electrode body according to the first embodiment.

[0011] Figure 5 This is a plan view showing the state at which the first electrode sheet and the second electrode sheet of the first embodiment begin to be wound.

[0012] Figure 6 This is a cross-sectional view showing a first variation of the first embodiment.

[0013] Figure 7 This is a plan view showing a second variation of the first embodiment.

[0014] Figure 8 It is shown Figure 7 A plan view of a variant example.

[0015] Figure 9 This is a cross-sectional view showing the configuration of the energy storage unit according to the second embodiment.

[0016] Figure 10 It is along Figure 9 A cross-sectional view along the XX line.

[0017] Figure 11 This is a cross-sectional view showing the configuration of the energy storage unit according to the third embodiment.

[0018] Figure 12 This is a perspective view showing the state at which the first electrode sheet and the second electrode sheet of the third embodiment begin to be wound.

[0019] Figure 13 This is a perspective view showing the state at which the first and second electrode sheets of a modified example of the third embodiment begin to be wound.

[0020] Figure 14 This is a cross-sectional view showing the configuration of the energy storage unit according to the fourth embodiment.

[0021] Figure 15 This is a perspective view showing the state at which the first electrode sheet and the second electrode sheet of the fourth embodiment begin to be wound.

[0022] Figure 16 This is a cross-sectional view showing the configuration of an energy storage unit according to a modified example of this disclosure.

[0023] Figure 17 This is a diagram showing the flow path of the energy storage unit and the heating medium in a modified embodiment of this disclosure.

[0024] Figure 18 This is a diagram showing the wound electrode body and electrode tabs of a modified energy storage unit according to the present disclosure. Detailed Implementation

[0025] Embodiments of this disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings referred to below, identical or equivalent components are labeled with the same numbers.

[0026] <First Implementation>

[0027] Figure 1This is a perspective view showing the configuration of an energy storage device 1 including an energy storage unit 100 according to an embodiment of the present disclosure. The energy storage device 1 is, for example, mounted on a vehicle (not shown). Examples of vehicles include hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles. Furthermore, the energy storage device 1 may also be installed in an electrical device other than an electric vehicle (e.g., a stationary energy storage device).

[0028] Furthermore, the X, Y, and Z directions in this specification are mutually orthogonal. For example, the X and Y directions can be the front-back and left-right directions, respectively, when the energy storage device 1 is mounted on an electric vehicle. Additionally, the Z direction can be the up-down direction. Specifically, the Z1 and Z2 directions can be up and down, respectively. Furthermore, the Z direction is an example of the "axial direction" of this disclosure.

[0029] The energy storage device 1 is mounted on a frame member 2 located at the bottom of the vehicle. The frame member 2 is formed into a generally quadrangular cylindrical shape that surrounds the energy storage device 1.

[0030] The energy storage device 1 includes multiple energy storage stacks 3. Each energy storage stack 3 is formed as a cuboid elongated in the Y direction. The multiple energy storage stacks 3 are arranged in a manner aligned along the X direction. Each energy storage stack 3 includes multiple energy storage cells 100 arranged along the Y direction. Furthermore, in Figure 1 For simplicity, only two energy storage stacks 3 are shown in the figure, and only three energy storage units 100 in each energy storage stack 3 are shown.

[0031] Figure 2 This is a perspective view showing the energy storage unit 100 of this embodiment. (As shown...) Figure 2 As shown, the energy storage unit 100 is a so-called square battery. The energy storage unit 100 is configured as a rechargeable battery. The energy storage unit 100 can be a rechargeable battery such as a lithium-ion battery or a nickel-metal hydride battery. The energy storage unit 100 can, for example, be used as a unit included in an energy storage module mounted in an electric vehicle.

[0032] The energy storage unit 100 includes a wound electrode body 10, a housing 20, a first external terminal 30A, a second external terminal 30B, a first terminal support portion 40A, and a second terminal support portion 40B. Furthermore, in Figure 2 In the diagram, the wound electrode body 10 is shown in a stylized manner with dashed lines.

[0033] The housing 20 is conductive. The conductive parts of the housing 20 are made of a metal such as aluminum. The housing 20 houses the wound electrode body 10 and the core portion 90, which will be described later. The housing 20 also houses the electrolyte (not shown in the figure).

[0034] The housing 20 includes a housing body 21 and a cover 22. When viewed in the Z direction from a position P away from the core portion 90 described later, the housing 20 has a quadrilateral shape (rectangular shape). The housing body 21 includes a bottom wall 210 and a peripheral wall 211 rising from the bottom wall 210.

[0035] The cover 22 includes a cover body 220 and an insulating cover 221. The cover body 220 is joined to the peripheral wall 211 by welding or the like in a manner that seals the opening of the peripheral wall 211.

[0036] The first external terminal 30A and the second external terminal 30B are provided to be exposed to the outside in the energy storage unit 100. Furthermore, in this embodiment, the first external terminal 30A is the positive terminal and the second external terminal 30B is the negative terminal. The first external terminal 30A and the second external terminal 30B are arranged in the X direction.

[0037] The first terminal support 40A is secured to the cover body 220. The first terminal support 40A supports the first external terminal 30A from the outer periphery of the first external terminal 30A. The second terminal support 40B is secured to the cover body 220. The second terminal support 40B supports the second external terminal 30B from the outer periphery of the second external terminal 30B.

[0038] Figure 3 This is an exploded perspective view of the energy storage unit 100 according to this embodiment. The energy storage unit 100 also includes a first connecting structural member 50A, a second connecting structural member 50B, a first sealing ring 60A, a second sealing ring 60B, an insulating member 70, a fuse protection part 80, and a winding core part 90. Furthermore, the first connecting structural member 50A and the second connecting structural member 50B are each examples of the "current collector" of this disclosure.

[0039] The bottom wall 210 includes a bottom body 212, an outer protective membrane 213, and an inner protective membrane 214. A peripheral wall 211 rises from the bottom body 212. A pressure relief valve SV is provided on the bottom body 212. The outer protective membrane 213 covers the pressure relief valve SV from the outside. The inner protective membrane 214 covers the pressure relief valve SV from the inside. The bottom body 212 and the pressure relief valve SV are made of metal such as aluminum.

[0040] An opening is formed at the upper end of the peripheral wall 211. The peripheral wall 211 is positioned such that the opening direction (position P) is... Figure 2When observed, it has a roughly rectangular shape. The openings and bottom wall 210 are arranged in the Z direction. The openings are located on the Z1 side of the bottom wall 210. The Z direction can be the height direction of the energy storage unit 100 or the vertical direction. The peripheral wall 211 is made of a metal such as aluminum.

[0041] The cover 22 also includes a sealing plug 222 and a plug cover 223. A first connecting hole 224A, a second connecting hole 224B, and an injection hole 225 are formed in the cover body 220. The injection hole 225 is a through hole used to inject electrolyte into the housing body 21 during the manufacturing process of the energy storage unit 100.

[0042] The sealing plug 222 seals the injection hole 225. The plug cover 223 covers the injection hole 225 and the sealing plug 222. The insulating cover 221 covers the injection hole 225, the sealing plug 222, and the plug cover 223.

[0043] The first connecting structural member 50A and the second connecting structural member 50B are conductive. At least a portion of the first connecting structural member 50A and the second connecting structural member 50B is disposed within the housing 20. The first connecting structural member 50A and the second connecting structural member 50B are each disposed in a position opposite to the wound electrode body 10 in the Z direction. The first connecting structural member 50A and the second connecting structural member 50B are each disposed on the Z1 side of the wound electrode body 10.

[0044] The first external terminal 30A or the first connecting member 50A is inserted into the first connecting hole 224A. The first external terminal 30A and the first connecting member 50A are engaged with each other. The first connecting member 50A is engaged with the wound electrode body 10. Thus, the first external terminal 30A is electrically connected to the wound electrode body 10.

[0045] The second external terminal 30B or the second connecting member 50B is inserted into the second connecting hole 224B. The second external terminal 30B and the second connecting member 50B are engaged with each other. The second connecting member 50B is engaged with the wound electrode body 10. Thus, the second external terminal 30B is electrically connected to the wound electrode body 10.

[0046] A first sealing ring 60A is disposed along the first connecting hole 224A. The first sealing ring 60A is disposed in the gap between the cover body 220 and the first external terminal 30A, sealing the gap. A second sealing ring 60B is disposed along the second connecting hole 224B. The second sealing ring 60B is disposed in the gap between the cover body 220 and the second external terminal 30B, sealing the gap. The first sealing ring 60A and the second sealing ring 60B are electrically insulating.

[0047] The first terminal support portion 40A includes a first locking ring 41A and a first covering ring 42A. The first locking ring 41A extends annularly around the first connecting hole 224A and is directly locked to the cover body 220. The first covering ring 42A covers the first locking ring 41A. The first locking ring 41A supports the first external terminal 30A via the first covering ring 42A. The first covering ring 42A is made of a resin member having electrical insulation or relatively weak conductivity.

[0048] The second terminal support portion 40B includes a second locking ring 41B and a second covering ring 42B. The second locking ring 41B extends annularly around the second connecting hole 224B and is directly locked to the cover body 220. The second covering ring 42B covers the second locking ring 41B. The second locking ring 41B supports the second external terminal 30B via the second covering ring 42B. The second covering ring 42B is made of an electrically insulating resin component.

[0049] The insulating member 70 is electrically insulating. The insulating member 70 is disposed between the wound electrode body 10 and the housing 20. The insulating member 70 electrically insulates the wound electrode body 10 and the housing 20 from each other. The insulating member 70 includes an insulating bracket 71, a peripheral insulating portion 72, a bottom insulating portion 73, and an adhesive tape 74.

[0050] An insulating bracket 71 is disposed between the wound electrode body 10 and the cover body 220. The insulating bracket 71 has high rigidity and is in contact with both the wound electrode body 10 and the cover body 220. Thus, the wound electrode body 10 is fixed to the housing 20 in the Z direction.

[0051] The peripheral insulating portion 72 is disposed between the wound electrode body 10 and the peripheral wall 211. The wound electrode body 10 is composed of a film-like component.

[0052] The bottom insulating portion 73 is disposed between the wound electrode body 10 and the bottom wall 210. The bottom insulating portion 73 is composed of a film-like component. The bottom insulating portion 73 is fixed (bonded) to the housing 20 (bottom wall 210) by an adhesive tape 74.

[0053] The core portion 90 is conductive. The winding electrode body 10 is wound around the core portion 90. The winding electrode body 10 is electrically connected to the core portion 90.

[0054] The core portion 90 extends in the Z direction. The core portion 90 protrudes from the upper end face 101 of the winding electrode body 10 towards the Z1 side. Furthermore, the core portion 90 does not protrude from the lower end face (not shown) of the winding electrode body 10 towards the Z2 side (see reference). Figure 4 ).

[0055] The winding core 90 includes a first metal electrode 91, a second metal electrode 92, and an insulating layer 93. In this embodiment, the first electrode 91 may be a metal on the positive side, for example, formed of aluminum. The second electrode 92 may be a metal on the negative side, for example, formed of copper. The insulating layer 93 may be formed of resin, for example. The first electrode 91 and the second electrode 92 have the same shape and size. Each of the first electrode 91 and the second electrode 92 has a cuboid shape. The insulating layer 93 insulates the first electrode 91 from the second electrode 92. The insulating layer 93 has a cuboid shape. Therefore, the winding core 90 has a cuboid shape. Furthermore, in this disclosure, the cuboid shape has a broad meaning that also includes a cubic shape. In addition, the first electrode 91 and the second electrode 92 are examples of "positive side metal" and "negative side metal" of this disclosure, respectively.

[0056] Figure 4 This is a cross-sectional view of the wound electrode body 10 in the XZ plane. The wound electrode body 10 includes a first electrode sheet 10A and a second electrode sheet 10B. The first electrode sheet 10A and the second electrode sheet 10B have a sheet-like shape. The wound electrode body 10 is composed of an electrode plate group obtained by winding the first electrode sheet 10A and the second electrode sheet 10B. Furthermore, the first electrode sheet 10A and the second electrode sheet 10B are each examples of the "electrode sheet" of this disclosure.

[0057] In conventional energy storage units, the wound electrode body is electrically connected to the current collector by connecting the electrode tabs provided on the electrode plates to the current collector (connecting structural member). In this case, the presence of electrode tabs complicates the configuration of the wound electrode body.

[0058] In the first embodiment, the first electrode 91 of the core portion 90 is connected to the first electrode sheet 10A and the first connecting member 50A, respectively. Furthermore, the second electrode 92 of the core portion 90 is connected to the second electrode sheet 10B and the second connecting member 50B, respectively.

[0059] Therefore, without the need for electrode tabs, the first electrode plate 10A can be electrically connected to the first connecting member 50A, and the second electrode plate 10B can be electrically connected to the second connecting member 50B. This simplifies the configuration of the wound electrode body 10.

[0060] Furthermore, by making the core portion 90 rectangular, the outer shape of the wound electrode body 10 can be formed in a rectangular shape, thus suppressing the formation of dead space between the corners of the wound electrode body 10 and the housing 20. As a result, the volumetric efficiency of the wound electrode body 10 can be improved.

[0061] Refer again Figure 4The upper end face 91a of the first electrode 91 contacts the lower surface 51A of the first connecting member 50A. The upper end face 91a and the lower surface 51A can be joined by ultrasonic welding or the like. The upper end face 92a of the second electrode 92 contacts the lower surface 51B of the second connecting member 50B. The upper end face 92a and the lower surface 51B can be joined by ultrasonic welding or the like.

[0062] The first electrode sheet 10A is formed by stacking a positive electrode sheet 11A, a separator 12A, a negative electrode sheet 13A, and a separator 14A in that order. The positive electrode sheet 11A, separator 12A, negative electrode sheet 13A, and separator 14A are stacked sequentially from the core portion 90 side. The first electrode sheet 10A is fixed to the core portion 90 by connecting the positive electrode sheet 11A to the first electrode 91. Thus, the first electrode sheet 10A is electrically connected to the first electrode 91. Furthermore, separator 12A and separator 14A are examples of the "first separator" and "second separator" of this disclosure, respectively. Additionally, the positive electrode sheet 11A and negative electrode sheet 13A are examples of the "first positive electrode sheet" and "first negative electrode sheet" of this disclosure, respectively.

[0063] The second electrode 10B is formed by stacking the negative electrode 11B, separator 12B, positive electrode 13B, and separator 14B in that order. The negative electrode 11B, separator 12B, positive electrode 13B, and separator 14B are arranged sequentially from the core portion 90 side. The second electrode 10B is fixed to the core portion 90 by connecting the negative electrode 11B to the second electrode 92. Thus, the second electrode 10B is electrically connected to the second electrode 92. Furthermore, separator 12B and separator 14B are examples of the "third separator" and "fourth separator" of this disclosure, respectively. Additionally, negative electrode 11B and positive electrode 13B are examples of the "second negative electrode" and "second positive electrode" of this disclosure, respectively.

[0064] The outer peripheral edge of the separator 14A or separator 14B disposed on the outermost periphery of the winding electrode body 10 is fixed by a strip member (not shown).

[0065] In each of the aforementioned positive electrode plates 11A and 13B, a current collector (not shown) and a positive electrode active material layer (not shown) are stacked. In each of the negative electrode plates 13A and 11B, a current collector (not shown) and a negative electrode active material layer (not shown) are stacked.

[0066] like Figure 4 As shown, the first electrode 10A and the second electrode 10B are in a direction intersecting the Z direction ( Figure 4 The core is arranged alternately in the X direction. In addition, the direction that intersects the Z direction (hereinafter, sometimes referred to as the intersection direction) means the direction that leaves the core 90 in the XY plane.

[0067] The first electrode sheet 10A and the second electrode sheet 10B, which are adjacent in the intersecting direction, are insulated by a separator 14A or a separator 14B. Thus, the first electrode sheet 10A and the second electrode sheet 10B can be insulated from each other while being wound around a common core portion 90.

[0068] The first electrode 91 and the second electrode 92 when from position P ( Figure 2 During observation, the electrodes are arranged with the insulating layer 93 in between. This allows the first electrode piece 10A connected to the first electrode 91 and the second electrode piece 10B connected to the second electrode 92 to easily overlap in the intersecting direction.

[0069] The first electrode 91 is disposed on the X1 side of the insulating layer 93. The second electrode 92 is disposed on the X2 side of the insulating layer 93. The insulating layer 93 is in contact with the first electrode 91 and the second electrode 92 respectively. That is, no gap is formed between the insulating layer 93 and each of the first electrode 91 and the second electrode 92.

[0070] The aforementioned separators allow ions to move between adjacent positive and negative electrode plates while simultaneously separating the positive and negative electrode plates. These ions are, for example, lithium ions. Each separator is electrically insulating.

[0071] Figure 5 This diagram shows an example of the starting state of the winding of the first electrode sheet 10A and the second electrode sheet 10B. The first electrode 91 has a side surface 91b on the Y1 side, a side surface 91c on the Y2 side, and a side surface 91d connecting side surface 91b and side surface 91c. Side surface 91d is the side opposite to the insulating layer 93. The second electrode 92 has a side surface 92b on the Y2 side, a side surface 92c on the Y1 side, and a side surface 92d connecting side surface 92b and side surface 92c. Side surface 92d is the side opposite to the insulating layer 93. The insulating layer 93 has a side surface 93a on the Y1 side and a side surface 93b on the Y2 side.

[0072] The first electrode piece 10A is joined to the side surface 91b of the first electrode 91 by ultrasonic welding or the like. The first electrode piece 10A extends from side surface 91b towards sides 91c and 91d (in... Figure 5 (Wrapped in a counter-clockwise direction)

[0073] The second electrode piece 10B is joined to the side surface 92b of the second electrode 92 by ultrasonic welding or the like. The second electrode piece 10B extends from side surface 92b toward sides 92c and 92d (in... Figure 5 (Wrapped in a counter-clockwise direction)

[0074] The winding start end 15A of the first electrode sheet 10A is located at the boundary between the side surface 91b of the first electrode 91 and the side surface 93a of the insulating layer 93. Alternatively, the winding start end 15A may also be disposed on the side surface 93a. Similarly, the winding start end 15B of the second electrode sheet 10B is located at the boundary between the side surface 92b of the second electrode 92 and the side surface 93b of the insulating layer 93. Alternatively, the winding start end 15B may also be disposed on the side surface 93b. This prevents the second electrode sheet 10B from conducting with the first electrode 91, and also prevents the first electrode sheet 10A from conducting with the second electrode 92.

[0075] The first electrode 91 has a corner portion 91e and a corner portion 91f. Corner portion 91e connects side surface 91b and side surface 91d. Corner portion 91f connects side surface 91c and side surface 91d. Corner portions 91e and 91f may each have a shape (smooth shape) after the sharp corners are removed by chamfering (R-processing) or the like. Therefore, it is possible to suppress the first electrode 91 from being damaged by corner portions 91e and 91f.

[0076] The second electrode 92 has corner portions 92e and 92f. Corner portion 92e connects side surface 92b to side surface 92d. Corner portion 92f connects side surface 92c to side surface 92d. Corner portions 92e and 92f can each be formed in the same manner as corner portions 91e and 91f.

[0077] The first electrode sheet 10A has a portion 16A and a portion 17A. Portion 16A is the portion that contacts corner 91e. Portion 17A is the portion that contacts corner 91f. Both portions 16A and 17A are formed such that the surface on the side of the first electrode 91 is recessed towards the side opposite to the first electrode 91. This allows the first electrode sheet 10A to be easily bent.

[0078] The second electrode sheet 10B has a portion 16B and a portion 17B. The portion 16B is the portion that contacts the corner portion 92e. The portion 17B is the portion that contacts the corner portion 92f. The portions 16B and 17B are each formed such that the surface on the side of the second electrode 92 is recessed toward the side opposite to the second electrode 92.

[0079] <Modifications of the first embodiment>

[0080] Figure 6 A first variation of the first embodiment is shown. In the first variation, a void Ga is formed between the first electrode 91 and the second electrode 92 without an insulating layer.

[0081] Figure 7A second variation of the first embodiment is shown. The winding start end 15A of the first electrode sheet 10A is inserted into the recess 91g formed on the side surface 91d of the first electrode 91. The winding start end 15A is engaged with the surface 91h of the recess 91g. Furthermore, the recess 91g may also be filled with an adhesive material or the like. In addition, the corner 91i of the opening end of the recess 91g may also be formed into a smooth shape by chamfering (R-processing) or the like.

[0082] Furthermore, the winding start end 15B of the second electrode sheet 10B is also similarly inserted into the recess 92g formed on the side 92d of the second electrode 92. Moreover, the shape of the recess 92g is the same as that of the recess 91g, therefore a detailed description is omitted.

[0083] An insulating sheet 94 is disposed on the first electrode 91. The insulating sheet 94 spans the portion between the corner 91e and the recess 91g in the side surface 91d and the side surface 91b. An insulating sheet 95 is disposed on the second electrode 92. The insulating sheet 95 spans the portion between the corner 92e and the recess 92g in the side surface 92d and the side surface 92b. This prevents the first electrode sheet 10A from conducting with the second electrode 92, and also prevents the second electrode sheet 10B from conducting with the first electrode 91. Furthermore, it mitigates the surface roughness of both the first electrode 91 and the second electrode 92. Additionally, the insulating sheet 94 may extend from the side surface 93a of the insulating layer 93 to the recess 91g. The insulating sheet 95 may also extend from the side surface 93b of the insulating layer 93 to the recess 92g.

[0084] Furthermore, the locations where recesses are formed are not limited to the examples mentioned above. Figure 8 In the example shown, the recess 191g is formed at the corner of the first electrode 91 on the side of the insulating layer 93. The recess 192g is formed at the corner of the second electrode 92 on the side of the insulating layer 93.

[0085] <Second Implementation Method>

[0086] Next, the energy storage unit 300 according to the second embodiment of this disclosure will be described. Furthermore, configurations identical to those in the first embodiment will be labeled with the same reference numerals as those in the first embodiment. Additionally, sometimes configurations identical to those in the first embodiment will be described using the same names as those in the first embodiment, and detailed descriptions will be omitted.

[0087] Figure 9 A cross-sectional view of the energy storage unit 300 is shown. The energy storage unit 300 includes a wound electrode body 310, a housing 320, and a core portion 390.

[0088] The core portion 390 is formed of metal (e.g., aluminum) on the positive electrode side. The core portion 390 has a generally square shape when viewed from the Z direction. As a result, the outer shape of the wound electrode body 310 also has a generally square shape. The housing 320 also has a generally square shape when viewed from the Z direction.

[0089] Figure 10 It is along Figure 9 A cross-sectional view along line XX. The wound electrode body 310 includes a first electrode sheet 10A and at least one negative electrode tab 311. In the second embodiment, a plurality of negative electrode tabs 311 are provided. The first electrode sheet 10A is wound around the core portion 390. The core portion 390 is in contact with the positive electrode sheet 11A of the first electrode sheet 10A. Furthermore, a second electrode sheet 10B is not provided in the electrode body 310.

[0090] The housing 320 includes a bottom wall 321, a peripheral wall 322, a top plate 323, an insulating seal 324, and a bottom insulating portion 325. The bottom wall 321 may be integrally formed with the peripheral wall 322. Furthermore, the top plate 323 is an example of a "current collector" of this disclosure.

[0091] The upper end face 391 of the core portion 390 contacts the top plate 323 of the housing 320. As a result, the top plate 323 becomes positively charged.

[0092] Multiple negative electrode tabs 311 each connect the negative electrode plate 13A to the bottom wall 321 of the housing 320. As a result, the bottom wall 321 and the peripheral wall 322 are each negatively charged.

[0093] The bottom insulating portion 325 is disposed between the wound electrode body 310 (first electrode sheet 10A) and the bottom wall 321. A through hole 325a is formed in the bottom insulating portion 325 for a plurality of negative electrode tabs 311 to pass through.

[0094] An insulating seal 324 is circumferentially surrounding the top plate 323. The insulating seal 324 is formed in an annular shape. Thus, the peripheral wall 322 is electrically insulated from the top plate 323.

[0095] Alternatively, the core portion formed by the metal on the negative electrode side may contact the housing 320, and the positive electrode tab provided on the first electrode plate 10A may contact the housing 320.

[0096] <Third Implementation Method>

[0097] Figure 11 This is a diagram showing the energy storage unit 400 according to the third embodiment of this disclosure. Furthermore, for configurations identical to those in the second embodiment described above, the same reference numerals are used as in the second embodiment, and no further explanation is given.

[0098] The energy storage unit 400 includes a wound electrode body 410, a housing 320, and a core portion 490.

[0099] The winding core 490 includes a first electrode 491, a second electrode 492, and an insulating layer 493. The first electrode 491 and the second electrode 492 are arranged in the Z direction separated by the insulating layer 493. The first electrode 491 is disposed on the Z1 side of the second electrode 492. Furthermore, the first electrode 491 and the second electrode 492 are examples of the "positive electrode side metal" and "negative electrode side metal" of this disclosure, respectively.

[0100] With this configuration, compared to the case where the first electrode 491 and the second electrode 492 are arranged in the XY plane, the length of the outer periphery of the core portion 490 when viewed from the Z direction can be reduced. As a result, the length of the electrode sheet forming the wound electrode body 410 in the winding direction can be reduced.

[0101] The upper end face 491a of the first electrode 491 contacts the top plate 323 of the housing 320. The lower end face 492a of the second electrode 492 contacts the bottom wall 321 of the housing 320. Furthermore, in each of the third embodiment and the fourth embodiment described below, the bottom wall 321 is an example of the "current collector" of this disclosure.

[0102] like Figure 12 As shown, the wound electrode body 410 includes a first electrode sheet 410A and a second electrode sheet 410B. Figure 12 This is a diagram showing an example of the state in which the winding of the first electrode sheet 410A and the second electrode sheet 410B has begun. Furthermore, the first electrode sheet 410A and the second electrode sheet 410B are each examples of the "electrode sheet" of this disclosure.

[0103] The first electrode 491 has a side surface 491b on the Y1 side. The second electrode 492 has a side surface 492b on the Y2 side. The first electrode piece 410A can also be connected (joined) to the side surface 491b. The second electrode piece 410B can also be connected (joined) to the side surface 492b.

[0104] The first electrode sheet 410A includes a narrow portion 411A, a wide portion 412A, and a connecting portion 413A. The narrow portion 411A covers the side surface 491b of the first electrode 491. The narrow portion 411A is connected (joined) to the side surface 491b.

[0105] The width of the wide portion 412A in the Z direction is greater than that of the narrow portion 411A. Specifically, the Z2-side end 414A of the narrow portion 411A is located closer to the Z1 side than the Z2-side end 415A of the wide portion 412A. The end 414A is positioned closer to the Z1 side than the insulating layer 493 in the Z direction. Alternatively, the end 414A may be located within the insulating layer 493 in the Z direction. The end 415A is located closer to the Z1 side than the lower end face 492a of the second electrode 492 and closer to the Z2 side than the end 414B described later. Furthermore, the Z1-side ends of the narrow portion 411A, the wide portion 412A, and the connecting portion 413A are each located at the same position in the Z direction and are positioned closer to the Z2 side than the upper end face 491a of the first electrode 491.

[0106] The connecting portion 413A connects the narrow portion 411A and the wide portion 412A. The width of the connecting portion 413A in the Z direction increases as it approaches the wide portion 412A. The Z2-side end portion 416A of the connecting portion 413A is inclined towards the Z2 side as it approaches the wide portion 412A. The inclination angle of the end portion 416A is set such that the connecting portion 413A of the first electrode sheet 410A wound onto the core portion 490 does not contact the second electrode 492. Furthermore, a bend R may be formed at the connection portion between the end portion 416A and the end portion 414A.

[0107] The second electrode sheet 410B includes a narrow portion 411B, a wide portion 412B, and a connecting portion 413B. The narrow portion 411B covers the side surface 492b of the second electrode 492. The narrow portion 411B is connected (joined) to the side surface 492b.

[0108] The width of the wide portion 412B in the Z direction is greater than that of the narrow portion 411B. Specifically, the Z1-side end 414B of the narrow portion 411B is located closer to the Z2 side than the Z1-side end 415B of the wide portion 412B. The end 414B is positioned closer to the Z2 side than the insulating layer 493 in the Z direction. Alternatively, the end 414B may be located within the insulating layer 493 in the Z direction. The end 415B is located closer to the Z2 side than the upper end surface 491a of the first electrode 491 and closer to the Z1 side than the end 414A. Furthermore, the Z2-side ends of the narrow portion 411B, the wide portion 412B, and the connecting portion 413B are all located at the same position in the Z direction and are positioned closer to the Z1 side than the lower end surface 492a of the second electrode 492.

[0109] The connecting portion 413B connects the narrow portion 411B and the wide portion 412B. The width of the connecting portion 413B in the Z direction increases as it approaches the wide portion 412B. The Z2 side end 416B of the connecting portion 413B is inclined towards the Z1 side as it approaches the wide portion 412B. The inclination angle of the end 416B is set such that the connecting portion 413B of the second electrode sheet 410B wound onto the core portion 490 does not contact the first electrode 491. Furthermore, a bend R may be formed at the connection between the end 416B and the end 414B.

[0110] <Modifications of the Third Embodiment>

[0111] Figure 13 This is a perspective view showing a variation of the third embodiment described above. Figure 13 In the modified example, the narrow portion 411A extends from the side 491b towards the winding direction ( Figure 13 The middle section (X2 side) protrudes. Additionally, the narrow section 411B extends from the side 492b towards the winding direction ( Figure 13 The middle part (X1 side) protrudes.

[0112] <Fourth Implementation>

[0113] Figure 14 This is a cross-sectional view showing the energy storage unit 500 according to the fourth embodiment of this disclosure. Furthermore, for configurations identical to those in the above embodiments, the same reference numerals are used, and descriptions are not repeated.

[0114] The energy storage unit 500 includes a wound electrode body 10, a housing 320, and a core portion 590.

[0115] The winding core 590 includes a first electrode 591, a second electrode 592, and an insulating layer 593. The first electrode 591 and the second electrode 592 are each formed in an L-shape. By combining the first electrode 591 and the second electrode 592, a cuboid-shaped winding core 590 is formed. Furthermore, the first electrode 591 and the second electrode 592 are examples of the "positive electrode side metal" and "negative electrode side metal" of this disclosure, respectively.

[0116] The upper end face 591a of the first electrode 591 is in contact with the top plate 323 of the housing 320. The lower end face 592a of the second electrode 592 is in contact with the bottom wall 321 of the housing 320.

[0117] The first electrode 591 includes an upper end portion 591b and a downward extension portion 591c. The upper end portion 591b is a portion disposed at the Z1 side end of the first electrode 591 and has an upper end surface 591a. The downward extension portion 591c extends from the X1 side end of the upper end portion 591b toward the Z2 side. Furthermore, the upper end portion 591b extends from the upper end portion of the downward extension portion 591c toward the X2 side.

[0118] The second electrode 592 includes a lower end portion 592b and an upward extension portion 592c. The lower end portion 592b is a portion disposed at the end of the second electrode 592 on the Z2 side and has a lower end surface 592a. The upward extension portion 592c extends from the end of the lower end portion 592b on the X2 side toward the Z1 side. Furthermore, the lower end portion 592b extends from the lower end portion of the upward extension portion 592c toward the X1 side.

[0119] The insulating layer 593 includes an upper end portion 593a, a lower end portion 593b, and a connecting portion 593c. The upper end portion 593a is a portion located at the Z1 side end of the insulating layer 593. The lower end portion 593b is a portion located at the Z2 side end of the insulating layer 593. The connecting portion 593c connects the upper end portion 593a and the lower end portion 593b. The upper end portion 593a extends from the upper end portion of the connecting portion 593c toward the X2 side. The upper end portion 593a extends to the X2 side surface 592d of the second electrode 592. The lower end portion 593b extends from the lower end portion of the connecting portion 593c toward the X1 side. The lower end portion 593b extends to the X1 side surface 591d of the first electrode 591.

[0120] The upper end portion 593a of the insulating layer 593 is disposed between the upper end portion 591b of the first electrode 591 and the upward extension portion 592c of the second electrode 592. The lower end portion 593b of the insulating layer 593 is disposed between the downward extension portion 591c of the first electrode 591 and the lower end portion 592b of the second electrode 592. The connecting portion 593c of the insulating layer 593 is disposed between the downward extension portion 591c and the upward extension portion 592c.

[0121] Figure 15 This diagram shows the state when the first electrode sheet 10A and the second electrode sheet 10B are each wound onto the core portion 590. The winding start end 15A of the first electrode sheet 10A is located in the side surface 594 on the Y1 side of the core portion 590, where the connection portion 593c of the insulating layer 593 is exposed. The winding start end 15B of the second electrode sheet 10B is located in the side surface 595 on the Y2 side of the core portion 590, where the connection portion 593c is exposed.

[0122] Furthermore, the Z1-side ends of the first electrode sheet 10A and the second electrode sheet 10B are each disposed in the Z direction within the range of the upper end portion 593a of the insulating layer 593. The Z2-side ends of the first electrode sheet 10A and the second electrode sheet 10B are each disposed in the Z direction within the range of the lower end portion 593b of the insulating layer 593.

[0123] <Other variations>

[0124] Figure 16The energy storage unit 600 shown includes a wound electrode body 10, a housing 320, and a core portion 690.

[0125] The core portion 690 includes a first electrode 691, a second electrode 692, and an insulating layer 693. The first electrode 691 and the second electrode 692 are each formed in a cuboid shape. The first electrode 691 and the second electrode 692 are arranged in the X direction separated by the insulating layer 693. Furthermore, the first electrode 691 and the second electrode 692 are examples of the "positive electrode side metal" and "negative electrode side metal" of this disclosure, respectively.

[0126] The upper end face 691a of the first electrode 691 is in contact with the top plate 323 of the housing 320. The lower end face 692a of the second electrode 692 is in contact with the bottom wall 321 of the housing 320.

[0127] The insulating layer 693 is sandwiched between a first electrode 691 and a second electrode 692 in the X direction. The first electrode 691 protrudes towards the Z1 side beyond the upper end portion 693a of the insulating layer 693. Furthermore, the first electrode 691 does not protrude towards the Z2 side relative to the lower end portion 693b of the insulating layer 693. The second electrode 692 protrudes towards the Z2 side beyond the lower end portion 693b of the insulating layer 693. Furthermore, the second electrode 692 does not protrude towards the Z1 side relative to the upper end portion 693a of the insulating layer 693.

[0128] Figure 17 This is a diagram showing an energy storage unit 700. The energy storage unit 700 includes a wound electrode body 410, a housing 720, and a core portion 790.

[0129] The core portion 790 includes a first electrode 791, a second electrode 792, and an insulating layer 793. The first electrode 791 and the second electrode 792 are arranged in the Z direction with the insulating layer 793 in between. The first electrode 791 and the second electrode 792 are examples of the "positive electrode side metal" and "negative electrode side metal" of this disclosure, respectively.

[0130] The upper end face 791a of the first electrode 791 is in contact with the top plate 723 of the housing 720. The lower end face 792a of the second electrode 792 is in contact with the bottom wall 721 of the housing 720.

[0131] A through hole 794 extending in the Z direction is formed in the core portion 790. The through hole 794 penetrates the first electrode 791, the insulating layer 793, and the second electrode 792 in the Z direction. The opening end 794a on the Z1 side of the through hole 794 is formed on the upper end surface 791a. The opening end 794b on the Z2 side of the through hole 794 is formed on the lower end surface 792a.

[0132] A through hole 720a is formed in the top plate 723. The through hole 720a communicates with the through hole 794 via the opening end 794a of the through hole 794 in the core portion 790. A through hole 721a is formed in the bottom wall 721. The through hole 721a communicates with the through hole 794 via the opening end 794b of the through hole 794.

[0133] The through hole 720a of the top plate 723 is connected to the first end 1100 of the flow path 1000. The through hole 721a of the bottom wall 721 is connected to the second end 1200 of the flow path 1000. A pump 1300 and a radiator 1400 are provided on the external part of the energy storage unit 700 in the flow path 1000. The flow path 1000 is for the flow of a heat medium such as coolant or fire extinguishing liquid. The pump 1300 can be a water pump. In addition, if fire extinguishing liquid is used for flow, the radiator 1400 may not be provided. Alternatively, inert gas may be used instead of fire extinguishing liquid for flow.

[0134] Therefore, when a heat medium such as coolant flows through the flow path 1000, the energy storage unit 700 can be cooled and temperature deviations within the energy storage unit 700 can be suppressed. When a fire extinguishing liquid (or inert gas) flows through the flow path 1000, fire extinguishing of the energy storage unit 700 can be performed. Furthermore, a liquid containing a fire extinguishing agent added to the heat medium for cooling can also flow through the flow path 1000.

[0135] Alternatively, it could also be, Figure 17 The variations shown are also applicable to the above-described embodiments and their variations.

[0136] Figure 18 This is a cross-sectional view showing the energy storage unit 800. The energy storage unit 800 includes a wound electrode body 510. The wound electrode body 510 differs from the wound electrode body 10 of the first embodiment described above in that it includes at least one positive electrode tab 511 and at least one negative electrode tab 512. Figure 18 Although only one positive electrode tab 511 and one negative electrode tab 512 are shown in the figure, multiple positive electrode tabs 511 and multiple negative electrode tabs 512 may also be provided. In addition, the positive electrode tab 511 and the negative electrode tab 512 are each examples of the "electrode tabs" of this disclosure.

[0137] The positive electrode tab 511 is connected to the positive electrode plate 11A of the first electrode plate 10A. The positive electrode tab 511 protrudes from the positive electrode plate 11A toward the first connecting structure member 50A (Z1 side). Specifically, the positive electrode tab 511 protrudes from the portion of the positive electrode plate 11A that is located on the outer periphery side of the innermost peripheral side. The positive electrode tab 511 is connected to the side surface 91d on the X1 side of the first electrode 91.

[0138] The negative electrode tab 512 is connected to the negative electrode plate 11B of the second electrode plate 10B. The negative electrode tab 512 protrudes from the negative electrode plate 11B toward the side (Z1 side) of the second connecting structure 50B. Specifically, the negative electrode tab 512 protrudes from the portion of the negative electrode plate 11B that is located on the outer periphery side of the innermost peripheral side. The negative electrode tab 512 is connected to the side surface 92d on the X2 side of the second electrode 92.

[0139] With this configuration, the current collection efficiency on the positive electrode side can be improved using the positive electrode tab 511. Furthermore, the current collection efficiency on the negative electrode side can be improved using the negative electrode tab 512. In addition, since the innermost positive electrode plate 11A is directly connected to the first electrode 91, the desired current collection efficiency can be easily achieved even by reducing the number of positive electrode tabs 511 compared to the case where the innermost positive electrode plate 11A is not connected to the first electrode 91. Similarly, the desired current collection efficiency can be easily achieved even by reducing the number of negative electrode tabs 512 compared to the case where the innermost negative electrode plate 11B is not connected to the second electrode 92. Therefore, the configuration of the wound electrode body 510 can be easily simplified.

[0140] Alternatively, only either the positive electrode tab 511 or the negative electrode tab 512 may be provided. Figure 18 The variations shown can also be applied to the variations described above. Alternatively, the positive electrode tab 511 can be directly connected to the first connecting member 50A. The negative electrode tab 512 can also be directly connected to the second connecting member 50B.

[0141] In the above embodiments and variations, examples are shown where the first electrode and the second electrode have the same shape and size. However, this disclosure is not limited thereto, and the first electrode and the second electrode may also have different shapes and sizes.

[0142] In the above-described embodiments and variations, examples are shown where the electrode sheet is directly wound onto the core portion, but this disclosure is not limited thereto. For example, the surface of the electrode may be pretreated to form an electrode layer. The electrode sheet is then wound over the electrode layer. This reduces the surface roughness of the electrode and lowers the resistance between the electrode and the electrode sheet.

[0143] The above-described embodiments and variations can also be combined with each other.

[0144] Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of this disclosure is defined not by the description of the embodiments above but by the claims, and therefore includes all modifications within the scope and equivalent meaning of the claims.

Claims

1. An energy storage unit, comprising: Conductive core section; A wound electrode body, comprising electrode sheets wound around the periphery of the core portion; and A current collector is positioned opposite the winding electrode body along the axial direction extending from the core portion. The core portion has a cuboid shape and is connected to the electrode sheet and the current collector, respectively.

2. The energy storage unit according to claim 1, The electrode sheet includes a first electrode sheet and a second electrode sheet. The first electrode sheet is formed by stacking a first positive electrode sheet, a first separator, a first negative electrode sheet, and a second separator in this order. The second electrode plate is formed by stacking the second negative electrode plate, the third separator, the second positive electrode plate, and the fourth separator in this order. The core portion includes: Positive electrode side metal; Negative electrode side metal; as well as An insulating layer separates the positive electrode metal from the negative electrode metal. The first electrode sheet and the second electrode sheet are each wound around the core portion. The first electrode plate is fixed to the winding core by connecting the first positive electrode plate to the positive electrode side metal. The second electrode plate is fixed to the core portion by connecting the second negative electrode plate to the negative electrode side metal. In the direction intersecting the axial direction, the first electrode plate and the second electrode plate are arranged alternately. The first electrode plate and the second electrode plate adjacent to each other in the cross direction are insulated by the second separator or the fourth separator.

3. The energy storage unit according to claim 2, The positive electrode side metal and the negative electrode side metal are arranged apart from the insulating layer when viewed in the axial direction from a position away from the core portion.

4. The energy storage unit according to claim 2, The positive electrode metal and the negative electrode metal are arranged in the axial direction separated by the insulating layer.

5. The energy storage unit according to any one of claims 1 to 4, The wound electrode body includes electrode tabs electrically connected to the electrode sheet. The electrode tabs protrude from the electrode sheet toward the current collector and are connected to the core portion.

6. The energy storage unit according to any one of claims 1 to 4, The core portion has a through hole extending in the axial direction. The through hole is connected to a flow path for the flow of coolant or inert gas.

7. The energy storage unit according to any one of claims 1 to 4, The energy storage unit also includes a housing that accommodates the winding core and the wound electrode. The housing has a quadrilateral shape when viewed along the axial direction from a position away from the core portion.

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