Storage battery

Abstract

To provide a storage battery that can be controlled easily when an operation state exceeds expectation.SOLUTION: In a storage battery 10, a sealing film 44 is fused in each outer peripheral part of current collectors 30 of bipolar electrodes 14 adjacent in a stacking direction in an electrode laminate 18 and a spacer 42 is disposed between the sealing films 44 adjacent in the stacking direction. In addition, in the electrode laminate 18, a sealing part 50 is formed in such a way that an end surface side part of the sealing film 44 and an end surface side part of the spacer 42 are fused. In addition, a narrow part 52 whose width of the sealing part 50 is made narrower than the other part in a stacking direction view is formed at an outer surface 46A of the electrode laminate 18. Thus, in the storage battery 10, in the occurrence of an operation state exceeding expectation, a cleavage is generated in the sealing part 50 at the narrow part 52; thus, the control in the occurrence of the operation state exceeding the expectation can be easily performed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a storage battery. [Background technology]

[0002] Patent Document 1 discloses an electricity storage module used in an electricity storage device. The electricity storage module has an electrode stack in which bipolar electrodes and separators are alternately stacked and laminated, and the periphery of the stack is surrounded by a sealing body.

[0003] In the electrode laminate, the bipolar electrode has a positive electrode on one side of a current collector and a negative electrode on the other side, and the electrode laminate has a separator interposed between the positive electrode of one bipolar electrode and the negative electrode of the other bipolar electrode that are adjacent in the stacking direction. Also, in the bipolar electrode, the positive electrode and negative electrode are provided on the current collector, and the negative electrode covers the positive electrode when viewed in the stacking direction, and the peripheral portion of the current collector is left uncoated.

[0004] The sealing portion is composed of a first sealing portion and a second sealing portion, and the first sealing portion is formed into a rectangular cylindrical shape by welding to the peripheral portion of each of the bipolar electrode current collectors, and the second sealing portion covers the outer surface of the first sealing portion, making the internal space airtight. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-119669 Summary of the Invention [Problem to be solved by the invention]

[0006] In secondary batteries such as bipolar batteries, the temperature rises during charging and discharging, and the internal pressure in the sealing portion increases with the temperature rise. In order to avoid serious problems caused by the internal pressure increasing, it is preferable to effectively reduce the pressure inside the sealing portion.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a storage battery that can be easily controlled when the operating state exceeds the expected state. [Means for solving the problem]

[0008] a resin spacer disposed between the films at the peripheral edges of the current collectors adjacent in the stacking direction of the electrode laminate; a sealing portion formed by thermally welding the outer circumferential edges of the films adjacent in the stacking direction to the outer circumferential edges of the spacer in contact with the films, the sealing portion extending along the periphery of the electrode laminate as viewed in the stacking direction of the electrode laminate and sealing each internal space between the current collectors adjacent in the stacking direction; a narrow portion, on one of the outer surfaces of the electrode laminate on which the sealing portion is formed, having a width dimension, as viewed in the stacking direction, narrower than other portions of the sealing portion; and a laminate exterior portion having the electrode laminate housed within the sealed interior.

[0009] In the storage battery of the first embodiment, a bipolar electrode is used in which a positive electrode active material layer is disposed on one surface of a current collector and a negative electrode active material is disposed on the other surface, and a plurality of bipolar electrodes are stacked with separators interposed therebetween to form an electrode stack.

[0010] In the bipolar electrode, a film is disposed around the periphery of a current collector so as to sandwich the current collector, and the film is heat-welded to the current collector. Furthermore, in the electrode stack, a resin spacer is disposed between the films disposed around the periphery of the current collectors of adjacent bipolar electrodes in the stacking direction, and the film and spacer are overlapped around the entire periphery of the electrode stack in the stacking direction. Furthermore, the electrode stack is housed in a laminate exterior whose interior is sealed.

[0011] The electrode stack also has a sealing portion provided on each outer surface. The sealing portion is formed by thermally welding the outer peripheral edge of a film adjacent in the stacking direction to the outer peripheral edge of a spacer in contact with the film, and extends along the periphery of the electrode stack as viewed in the stacking direction of the electrode stack. As a result, the sealing portion seals between the spacer and the film welded to the current collector, thereby sealing the inside of the electrode stack.

[0012] Here, a narrow width portion is provided on one of the outer surfaces of the electrode stack. The sealing portion extends at a predetermined width along the outer surface of the electrode stack as viewed in the stacking direction of the electrode stack. The narrow width portion is formed on one of the outer surfaces of the electrode stack so as to make the width dimension of the sealing portion as viewed in the stacking direction of the electrode stack narrower than other portions.

[0013] As a result, the electrode stack is designed so that the sealing portion is more likely to rupture at the narrow portion when internal pressure (pressure within the internal space) is applied to one side of the electrode stack.By providing a narrow portion in the sealing portion, the electrode stack makes it possible to control the rupture position of the sealing portion when the operating state exceeds the expected state during charging and discharging.

[0014] The storage battery of the second aspect is the same as that of the first aspect, and further includes a detection unit that is arranged within the laminate exterior portion opposite the one surface of the electrode stack and that detects at least one of the temperature within the laminate exterior portion and the gas when the gas is generated within the electrode stack.

[0015] In the storage battery of the second aspect, a detector is provided in the laminate exterior for detecting at least one of the temperature and the gas emitted within the electrode stack. The detector faces one of the outer surfaces of the electrode stack on which the narrow width portion is provided. This allows efficient and rapid detection of an operating state of the electrode stack that exceeds an expected state, and by adjusting charge / discharge control based on the detection result, safety can be ensured.

[0016] A third aspect of the storage battery is the first or second aspect, wherein the one surface of the electrode stack is provided with an injection port for injecting an electrolyte solution into the internal space between the current collectors adjacent in the stacking direction.

[0017] In the storage battery of the third aspect, an inlet for injecting an electrolyte solution into the internal space between adjacent current collectors in the stacking direction is provided on one of the outer surfaces of the electrode stack where the narrow width portion is provided. This allows efficient and rapid detection of any deterioration in the sealing property of the inlet, and by adjusting the charge / discharge control based on the detection result, safety can be ensured. [Effects of the Invention]

[0018] According to an aspect of the present invention, in an electrode stack whose outer surfaces are sealed by a sealing portion, by providing a narrow width portion in the sealing portion on one of the outer surfaces, it has the effect of making it easier to control when the operating state exceeds expectations. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic configuration diagram showing a storage battery according to an embodiment of the present invention as viewed from the side. [Figure 2] 1 is a cross-sectional side view showing an outline of a battery module as a main part of a storage battery. [Figure 3] FIG. 2 is a plan view seen from above showing an outline of a battery module as a main part of a storage battery. [Figure 4] FIG. 2 is a side view showing one outer surface of the battery module. [Figure 5] FIG. 2 is an enlarged cross-sectional view of a main part of the battery module as viewed from above. DETAILED DESCRIPTION OF THE INVENTION

[0020] The storage battery 10 according to this embodiment will be described in detail below with reference to the drawings. Fig. 1 shows a schematic side view of a storage battery 10 according to this embodiment, and Fig. 2 shows a schematic side cross-sectional view of the main parts of the storage battery 10. Fig. 3 shows a schematic top plan view of the main parts of the storage battery 10.

[0021] In the drawings, the upward direction in the vertical direction is indicated by arrow Z (Z-axis), and the directions that intersect with the vertical direction and intersect with each other are indicated by arrow Y (Y-axis) and arrow X (X-axis). In the following description, the direction along arrow Z is referred to as the stacking direction, and the directions of arrow Y and arrow X are referred to as the horizontal direction. In the following description, the direction around the stacking direction of storage battery 10 is referred to as the circumferential direction, and the surface of storage battery 10 facing outward is referred to as the outer surface or side surface.

[0022] A laminated lithium-ion battery (lithium-ion secondary battery) is used as the storage battery 10. The storage battery 10 is not limited to a lithium-ion battery as long as it is a laminated battery, and may be another secondary battery such as a nickel-metal hydride secondary battery. A plurality of storage batteries 10 are electrically connected in series (or in parallel) to form a power storage device capable of outputting a predetermined voltage.

[0023] 1, 2, and 3, a storage battery 10 includes a battery module 12. The battery module 12 uses a plurality of bipolar electrodes 14 as electrodes (electrode bodies), and the battery module 12 includes an electrode stack 18 (see FIG. 2) in which the plurality of bipolar electrodes 14 are stacked with separators 16 (not shown in FIG. 1) interposed therebetween.

[0024] The storage battery 10 has a battery module 12 enclosed in a laminate exterior part 20. The storage battery 10 also has a sensor 22 as a detection part, and the sensor 22 is disposed in the laminate exterior part 20 and enclosed in the laminate exterior part 20 together with the battery module 12.

[0025] As shown in FIG. 2, the bipolar electrode 14 includes a current collector (current collecting foil) 30, which is formed into a foil using a metal material, a conductive resin material, a conductive inorganic material, or the like. The current collector 30 has, for example, a substantially rectangular shape when viewed from above (as viewed in the stacking direction). The current collector 30 is not limited to a foil shape, and may be formed into a plate, film, or mesh shape. In the bipolar electrode 14, the current collector 30 has, for example, a substantially rectangular shape when viewed from above, with the direction of arrow Y (vertical direction) longer than the direction of arrow X (horizontal direction).

[0026] The bipolar electrode 14 has a positive electrode active material layer 32 provided on one surface of a current collector 30 and a negative electrode active material layer 34 provided on the other surface. The positive electrode active material layer 32 is formed by coating one surface of the current collector 30 with a positive electrode active material, and the positive electrode active material layer 32 functions as a positive electrode. The negative electrode active material layer 34 is formed by coating the other surface of the current collector 30 (the surface opposite to the positive electrode active material layer 32) with a negative electrode active material, and the negative electrode active material layer 34 functions as a negative electrode.

[0027] When multiple bipolar electrodes 14 are stacked, the positive electrode active material layer 32 is on one side in the stacking direction, and the negative electrode active material layer 34 is on the other side in the stacking direction. When multiple bipolar electrodes 14 are stacked, a separator 16 is disposed between the positive electrode active material layer 32 of one bipolar electrode 14 and the negative electrode active material layer 34 of the other bipolar electrode 14 that are adjacent in the stacking direction. Thus, in the electrode stack 18, multiple bipolar electrodes 14 are stacked with the separator 16 interposed therebetween.

[0028] In the electrode stack 18, the bipolar electrode 14 at one end in the stacking direction is the positive terminal electrode 14A, and the bipolar electrode 14 at the other end in the stacking direction is the negative terminal electrode 14B. The current collector 30 of the positive terminal electrode 14A is not provided with a negative electrode active material layer 34, and the positive electrode active material layer 32 faces the negative electrode active material layer 34 of the adjacent bipolar electrode 14 with the separator 16 interposed therebetween. In addition, the current collector 30 of the negative terminal electrode 14B is not provided with a positive electrode active material layer 32, and the negative electrode active material layer 34 faces the positive electrode active material layer 32 of the adjacent bipolar electrode 14 with the separator 16 interposed therebetween.

[0029] In the bipolar electrode 14, when viewed from above (viewed in the stacking direction), the current collector 30 is sized to cover the positive electrode active material layer 32 and the negative electrode active material layer 34, and the negative electrode active material layer 34 is sized to cover the positive electrode active material layer 32. As a result, in the bipolar electrode 14, an uncoated portion (uncoated region; a region where the positive electrode active material and the negative electrode active material are not coated) is provided in the peripheral portion of the current collector 30, which is the peripheral portion around the stacking direction.

[0030] The separator 16 is sized to cover the negative electrode active material layer 34. As a result, in the electrode laminate 18, the entire surfaces of the positive electrode active material layer 32 and the negative electrode active material layer 34 of the bipolar electrode 14 are in contact with the separator 16, and the uncoated portions of the current collectors 30 protrude around the entire periphery (peripheral edge) of the positive electrode active material layer 32 and the negative electrode active material layer 34 when viewed in the stacking direction. In addition, in the electrode laminate 18, an internal space 36 is formed between the current collectors 30 of the bipolar electrodes 14 adjacent in the stacking direction.

[0031] The separator 16 electrically isolates the positive electrode active material layer 32 and the negative electrode active material layer 34 in the electrode laminate 18. Furthermore, in the electrode laminate 18, the separator 16 forms an electrolyte layer between the positive electrode active material layer 32 and the negative electrode active material layer 34, thereby preventing an electrical short circuit between the positive electrode active material layer 32 and the negative electrode active material layer 34 while allowing charge carriers such as lithium ions to pass through (permeate). This allows a predetermined voltage to be generated between the current collector 30 of the positive terminal electrode 14A and the current collector 30 of the negative terminal electrode 14B in the electrode laminate 18 (battery module 12).

[0032] A solid electrolyte layer containing a known solid electrolyte can be used for such separator 16. Alternatively, a porous film, woven fabric, or nonwoven fabric made of a required resin and impregnated with a liquid electrolyte can be used for separator 16. In this case, after forming the battery module 12, an electrolyte solution is injected around the positive electrode active material layer 32 and the negative electrode active material layer 34 (in the internal space 36 between the current collectors 30 adjacent in the stacking direction), so that the separator 16, along with the positive electrode active material layer 32 and the negative electrode active material layer 34, is impregnated with the electrolyte solution.

[0033] On the other hand, the battery module 12 is formed with a sealing portion 40 that seals each of the internal spaces 36 of the electrode stack 18. The sealing portion 40 uses a resin spacer 42 and a sealing film 44 that serves as a sealing material and film for sealing the peripheral edge of the current collector 30.

[0034] Fig. 4 shows a side view (side view of outer surface 46A) of one outer surface 46A of the multiple outer surfaces (side surfaces) 46 of the electrode stack 18 in the battery module 12. Fig. 5 shows a cross-sectional view of the portion of the electrode stack 18 on the outer surface 46A side in the battery module 12 as viewed in the stacking direction (from above).

[0035] 2 to 5, in the bipolar electrode 14, a sealing film 44 is disposed on the uncoated peripheral portion of the current collector 30, and the sealing film 44 is disposed along each of the four sides of the current collector 30. The sealing films 44 are strip-shaped with a predetermined width and are disposed in pairs so as to sandwich the peripheral portion of the current collector 30, and the sealing films 44 are overlapped on each of one surface and the other surface of the current collector 30.

[0036] In the bipolar electrode 14, two sealing films 44 are heat-welded to be one body and joined to the current collector 30. As a result, in the bipolar electrode 14, the sealing film 44 is arranged in a frame shape of a predetermined width on the peripheral portion of the current collector 30 when viewed from above, and the bipolar electrode 14 is sealed between the current collector 30 and the sealing film 44 along the entire peripheral portion (outer periphery) of the current collector 30.

[0037] The spacer 42 is made of a resin such as PE (polyethylene) and has a rectangular cross section. The spacer 42 has a dimension smaller than the width of the sealing film 44 when viewed from above, for example.

[0038] The spacers 42 are fitted between the sealing films 44 of the current collectors 30 adjacent in the stacking direction. In this case, the spacers 42 are arranged between the current collectors 30 of the bipolar electrodes 14 adjacent in the stacking direction, with the outer edge of the electrode stack 18 aligned (flush) with the edge of the sealing film 44.

[0039] As a result, in the electrode laminate 18, the current collectors 30 of adjacent bipolar electrodes 14 in the stacking direction are spaced at regular intervals by the spacers 42, and multiple bipolar electrodes 14 are stacked at regular intervals. Note that in the electrode laminate 18, the outer periphery of the separator 16 is fixed in position within the internal space 36 by being spot-welded to an adjacent sealing film 44 or the like in the stacking direction (for example, the sealing film 44 provided on the current collector 30 on the negative electrode active material layer 34 side).

[0040] On the other hand, in the electrode laminate 18, a seal portion 50 that forms the sealing portion 40 is provided on each outer surface 46 including the outer surface 46A, and in the electrode laminate 18, each outer surface 46 is covered with a seal portion 50, so that the entire periphery is covered with the seal portion 50. The seal portion 50 is formed on the outer surface 46 of the electrode laminate 18 by thermally welding an end surface portion of the spacer 42 on the outer surface 46 side and an end surface portion of the sealing film 44 on the outer surface 46 side.

[0041] In the electrode stack 18, the gap between the spacer 42 and the sealing film 44 provided on the current collector 30 is sealed by the sealing portion 50, thereby sealing the internal space 36 between the current collectors 30, and the sealing portion 50 seals the inside of the electrode stack 18. In the sealing portion 40, the sealing portion 50 covers the entire surface of each outer surface 46, and the sealing portion 50 covers the entire periphery of the electrode stack 18 in the stacking direction.

[0042] As a result, as shown in FIGS. 4 and 5, in the battery module 12, the seal portion 50 extends with a required width (required width dimension as a dimension in a direction intersecting the extending direction) when viewed in the stacking direction.

[0043] Here, in the battery module 12, a narrow width portion 52 is formed on an outer surface 46A, which is one of the outer surfaces 46 of the electrode stack 18. The narrow width portion 52 is formed on the outer surface 46A by making the width (width dimension) of the seal portion 50 narrower than other portions when viewed in the stacking direction. Furthermore, the narrow width portion 52 extends from one side end to the other side end on the outer surface 46A in the stacking direction.

[0044] In the electrode stack 18, the provision of the narrow width portion 52 makes a portion of the seal portion 50 structurally weaker. As a result, in the battery module 12, the seal portion is more likely to tear at the narrow width portion 52 than at other portions.

[0045] In the battery module 12, the seal portion 50 is formed so as to prevent rupture in portions other than the narrow width portion 52 even when the internal pressure of the internal space 36 exceeds a predetermined internal pressure (an internal pressure within an expected range). The narrow width portion 52 has a width (width dimension) that causes rupture when the internal pressure of the internal space 36 in the battery module 12 reaches the predetermined internal pressure.

[0046] A liquid electrolyte can be used in the storage battery 10. When a liquid electrolyte is used, the electrolyte solution is injected into the internal space 36 between the current collectors 30 adjacent in the stacking direction in the electrode stack 18. At this time, in the battery module 12, an injection port (not shown) for injecting the electrolyte solution is provided on the outer surface 46A of the electrode stack 18 where the narrow width portion 52 is formed in the seal portion 50. The injection port is closed (sealed) after the electrolyte solution has been injected into the internal space 36 of the electrode stack 18.

[0047] 1, the laminate exterior part 20 is made of, for example, two laminate films 20A (or one of the laminate films 20A may be folded back) whose peripheral edges are joined (melted) by heat welding or the like, thereby sealing the hollow interior of the laminate exterior part 20.

[0048] In the storage battery 10, a battery module 12 is disposed within a laminate exterior part 20. In the storage battery 10, a sensor 22 is disposed within the laminate exterior part 20. The sensor 22 is disposed within the laminate exterior part 20 so as to face an outer surface 46A of the battery module 12.

[0049] The sensor 22 may be a temperature sensor for detecting the temperature inside the laminate exterior part 20. Alternatively, the sensor 22 may be a gas sensor for detecting gas (air) generated during charging and discharging of the battery module 12 (during operation of the bipolar electrodes 14). The sensor 22 is connected to a monitoring device, a charge control device, or the like (not shown) for monitoring (charging and discharging control) the charging and discharging of the storage battery 10 in the storage battery 10 or in an electricity storage device using the storage battery 10.

[0050] In the storage battery 10 configured as described above, a plurality of bipolar electrodes 14 are used in the battery module 12. In each bipolar electrode 14, a positive electrode active material is applied to one surface of a current collector 30 to form a positive electrode active material layer 32, and a negative electrode active material is applied to the other surface to form a negative electrode active material layer 34. In addition, in each bipolar electrode 14, a sealing film 44 is heat-welded to the uncoated peripheral portion of the current collector 30, thereby integrating the sealing film 44 with the current collector 30.

[0051] In the battery module 12, when the bipolar electrodes 14 are stacked to form the electrode laminate 18, the spacers 42 are disposed between the sealing films 44 of the current collectors 30. In the electrode laminate 18, the end faces (ends on the end face side) of the sealing films 44 and the end faces (ends on the end face side) of the spacers 42 are thermally welded to form the seal portions 50, and the entire outer surface 46 of the electrode laminate 18 is covered with the seal portion 50.

[0052] Thereafter, laser welding using the energy of laser light can be applied to form the seal portion 50. In laser welding, laser light with a predetermined beam diameter (beam width) is irradiated onto the ends of the electrode stack 18, including the end faces of the spacers 42 and the sealing film 44, from above (one side in the stacking direction), to thermally weld the spacers 42 and the sealing film 44 over the entire surfaces of the outer surfaces 46.

[0053] At this time, the laser light is scanned along the outer surfaces 46 as viewed in the stacking direction, so that a seal portion 50 is formed on each outer surface 46 of the electrode stack 18, and the seal portion 50 extends along the outer surfaces 46 by a required width as viewed in the stacking direction. As a result, in the electrode stack 18, the space between the spacer 42 and the sealing film 44 is sealed, the internal space 36 is sealed, and the inside of the electrode stack 18 is sealed by the seal portion 50.

[0054] Furthermore, in the storage battery 10, the battery module 12 is enclosed in a laminate exterior part 20. At this time, in the storage battery 10, the sensor 22 is disposed facing the outer surface 46A of the battery module 12, and the sensor 22 is enclosed in the laminate exterior part 20 together with the battery module 12.

[0055] However, in the storage battery 10, a temperature rise occurs within the battery module 12 due to charging and discharging, and the temperature may become too high due to various factors such as deterioration due to usage conditions (charging and discharging conditions) and deterioration over time, or gas may be generated within the battery module 12 during charging and discharging.

[0056] Here, in the battery module 12 (electrode stack 18), the internal space 36 between the current collectors 30 (bipolar electrodes 14) adjacent in the stacking direction is sealed by the seal portion 50. This prevents gas and other vapors from leaking out of the internal space 36 of the battery module 12 in the storage battery 10 within the expected operating range.

[0057] Furthermore, in the battery module 12, a narrow width portion 52 is formed in the seal portion 50 on the outer surface 46A, and the width of the narrow width portion 52 as viewed in the stacking direction is narrower than that of the seal portion 50 in other locations. This results in a structure in the battery module 12 in which tearing occurs more easily on the outer surface 46A of the electrode stack 18 than on the other outer surfaces 46.

[0058] Therefore, in the storage battery 10, if the battery module 12 exceeds the expected operating state (charge / discharge state) and the pressure in the internal space 36 exceeds the expected state, the seal portion 50 will tear at the narrow portion 52 of the outer surface 46A.

[0059] Furthermore, in the storage battery 10, the sensor 22 is positioned opposite the outer surface 46A of the battery module 12 where the narrow width portion 52 is formed in the sealing portion 50, so that if the sealing portion 50 is torn, the occurrence of the torn portion can be quickly detected.

[0060] Furthermore, in the storage battery 10, when a liquid electrolyte is used in the separator 16 of the battery module 12, an injection port is provided on the outer surface 46A. Therefore, in the storage battery 10, if the sealing property (airtightness) of the injection port is reduced, the sensor 22 can quickly detect this reduction in airtightness.

[0061] In this way, in the storage battery 10, by providing the narrow width portion 52 in the seal portion 50 that seals the inside of the electrode stack 18 in the battery module 12, even if the seal portion 50 were to tear, the surface at which the tearing occurs can be controlled. Moreover, in the storage battery 10, because the battery module 12 is sealed in the laminate exterior portion 20, even if the seal portion 50 were to tear at the narrow width portion 52, it is possible to prevent gas and the like in the internal space 36 from leaking to the periphery of the laminate exterior portion 20.

[0062] In addition, in the storage battery 10, the sensor 22 is enclosed together with the battery module 12 in the laminate exterior part 20, and the sensor 22 is disposed facing the outer surface 46A of the battery module 12. As a result, in the storage battery 10, if the seal part 50 in the narrow width part 52 is torn or if the sealing property of the injection port is reduced, the sensor 22 can quickly detect this, and charge / discharge control is adjusted based on the detection result of the sensor 22, thereby enabling quick safety assurance. [Explanation of symbols]

[0063] 10. Storage battery 12 Battery Module 14 Bipolar Electrodes 16 Separator 18 Electrode laminate 20 Laminate exterior 22 Sensor (detection unit) 30 Current collector 32 Positive electrode active material layer 34 Negative electrode active material layer 36 Interior Space 40 Sealing part 42 spacer 44 Sealing film 46 Exterior 46A Outer surface (one of the outer surfaces) 50 Seal part (sealing part) 52 Narrow section.

Claims

1. an electrode stack in which a plurality of bipolar electrodes, each having a positive electrode active material layer disposed on one surface of a current collector and a negative electrode active material layer disposed on the other surface thereof, are stacked with separators interposed therebetween; a film disposed on the peripheral edge of the current collector so as to sandwich the current collector and heat-sealed thereto; a resin spacer disposed between the films at the peripheral edges of the current collectors adjacent in the stacking direction in the electrode stack; a sealing portion formed by thermally welding outer peripheral edges of the films adjacent to each other in the stacking direction to outer peripheral edges of the spacers in contact with the films, the sealing portion extending along the periphery of the electrode stack as viewed in the stacking direction of the electrode stack, and sealing each internal space between the current collectors adjacent to each other in the stacking direction; a narrow width portion, on one of the outer surfaces of the electrode stack on which the sealing portion is formed, in which the width dimension of the sealing portion as viewed in the stacking direction is narrower than that of other portions; a laminate exterior part in which the electrode stack is housed and sealed; A storage battery including:

2. 2. The storage battery according to claim 1, further comprising a detection unit disposed within the laminate exterior portion opposite the one surface of the electrode stack, for detecting at least one of the temperature within the laminate exterior portion and the gas generated within the electrode stack.

3. 3. The storage battery according to claim 1, wherein the one surface of the electrode stack is provided with an injection port through which an electrolyte solution is injected into the internal space between the current collectors adjacent in the stacking direction.

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