Electricity storage device and manufacturing method thereof

Abstract

To stabilize a sealing state of a case by a sealing member against a pressure increase in the case.SOLUTION: A power storage device comprises: a case (outer casing 4) having a housing part (6); a power storage element (8) in which an electrode tab (positive electrode tab 10 and a negative electrode tab 12) is formed on a winding end surface, and which is housed in the housing part; a sealing member (18) that is arranged in the housing part, in which a peripheral surface is crimped with an inner wall surface of the case by a fastening (fastening part 30) from the outer peripheral side of the case to seal an open part of the housing part; a support plate (collector board 14) for supporting it so as to be contacted to a surface directed to a bottom part side of the housing part of the sealing member; and a support member (a folder 20) that is arranged on the surface on the open part side of the housing part of the sealing member, and supports the sealing member with a pressure by an engagement of the open end (36) of the case to be fastened (vertical fastening part 32) toward the bottom part side of the housing part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a sealing technology for an opening of a case that houses an energy storage element. [Background technology]

[0002] In electricity storage devices such as electric double layer capacitors and electrolytic capacitors, a sealing material is placed over the opening of the case containing the electricity storage element and electrolyte, and the sealing material is then crimped together with the case to seal the device. This prevents leakage of gas or electrolyte between the storage section and the outside air, or the intrusion of foreign matter into the storage section, even if gas is generated by a chemical reaction in the electrolyte during operation of the electricity storage device. In addition, power storage devices are widely used in automobiles, etc., but are increasingly subject to the effects of external vibrations. For this reason, some power storage devices are supported by components that are partially placed and fixed within the opening of the case, for purposes such as improving the mounting strength of the board or other equipment on which the device is mounted and absorbing vibrations.

[0003] Regarding components to be installed in such energy storage devices, there is a component that has an annular seat plate and mounting feet protruding from its inside, in which the annular seat plate is placed on a sealing member placed inside the case and is crimped by bending the case opening (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Jikko No. 12051, Showa 38 Summary of the Invention [Problem to be solved by the invention]

[0005] During operation, a chemical reaction in the electrolyte solution generates gas, which can fill the case, causing an increase in the internal pressure of the case. In this case, gas tends to flow toward the opening inside the case, exerting pressure on the sealing material sealing the opening. As the internal pressure increases, the sealing material is pressed toward the opening, potentially causing partial deformation or displacement. In an energy storage device, the connection between the energy storage element and the external terminal must maintain sufficient strength and be electrically connected to obtain the required power. However, deformation or displacement of the sealing material can lead to a deterioration or disconnection of the connection. Such a change in the sealing condition of the opening caused by the sealing material can lead to issues such as an inability to supply power from the energy storage element or a decrease in power supply efficiency due to increased resistance caused by a deterioration in the connection.

[0006] Regarding such a problem, the configuration disclosed in Patent Document 1 does not disclose or suggest the problem of the present disclosure, and is therefore unable to solve the problem.

[0007] The inventors of the present disclosure have discovered that, with regard to an energy storage device in which an energy storage element connected to an external terminal is stored within a case and the opening is sealed with a sealing member, deformation and displacement of the sealing member due to an increase in internal pressure of the case can be suppressed by clamping the sealing member on both sides within the storage section between a current collecting plate and a support member pressed by crimping the opening edge of the case.

[0008] In view of the above problems and findings, an object of the present disclosure is to stabilize the sealing state of the case by the sealing member against an increase in pressure inside the case. [Means for solving the problem]

[0009] In order to achieve the above object, one aspect of the electricity storage device of the present disclosure includes: a case having a storage section; an electricity storage element having electrode tabs formed on winding end surfaces and stored in the storage section; a sealing member disposed in the storage section and crimped from the outer periphery of the case so that the peripheral surface is pressed against the inner wall surface of the case to seal the opening of the storage section; a support plate that contacts and supports the surface of the sealing member facing the bottom of the storage section; and a support plate that is disposed on the surface of the sealing member facing the opening of the storage section and presses and supports the sealing member by engaging with the open end of the case that is crimped toward the bottom of the storage section. and a second external terminal electrically connected to the storage element via the case, the second external terminal being in contact with the electrode tab of the anode or cathode arranged on the bottom side of the storage section. and a support member.

[0010] In the above-described electricity storage device, at least a part of the outer edge of the bottom side surface and the opening side surface of the sealing member of the case is sandwiched between the support plate and the support member.

[0011] In the above-described energy storage device, the support plate is a current collector plate having one surface in contact with the electrode tab and the other surface in contact with the sealing member, and having a first external terminal on a portion thereof, and the sealing member has a through-hole formed in a portion of its sealing surface through which the first external terminal protrudes from the current collector plate toward the opening, and holds the current collector plate through the first external terminal by receiving stress due to crimping from the outer periphery of the case.

[0013] In the above-described energy storage device, the electrode tabs include an anode tab formed on one winding end surface of the energy storage element and a cathode tab formed on the other winding end surface of the energy storage element, one of the anode tab and the cathode tab being welded to the support plate, and the other being fixedly connected to the bottom of the storage section by welding.

[0014] In order to achieve the above object, one aspect of a manufacturing method for an electricity storage device of the present disclosure includes the steps of: bringing one surface of a current collector plate into contact with an electrode tab formed on a wound end surface of an electricity storage element to electrically connect the electricity storage element to a first external terminal integrated with the current collector plate; and bringing the other surface of the current collector plate into contact with one surface of a sealing member disposed in a storage section of a case in which the electricity storage element is stored; placing a support member on a surface of the sealing member on the opening side of the storage section; crimping the outer periphery of the case to crimp the circumferential surface of the sealing member and an inner wall surface of the case to seal the opening; and crimping the open end of the case toward the current collector plate to crimp the open end and the support member; a step of pressing and supporting the closing member by the engagement of the a step of electrically connecting the electrode tab of the anode or cathode arranged on the bottom side of the storage portion and a second external terminal formed on the support member to the energy storage element via the case; Includes.

[0015] The manufacturing method of the above-mentioned energy storage device further includes a step of pressing the sealing member stored in the storage section with a predetermined force to position the sealing member at a set position in the storage section, and the crimping process from the outer periphery of the case and the crimping process on the opening end are performed in a state in which the sealing member is pressed. [Effects of the Invention]

[0017] According to the present disclosure, one of the following effects can be obtained.

[0018] (1) When the internal pressure of the case increases, deformation of the sealing member and displacement of the sealing member toward the opening of the case can be suppressed.

[0019] (2) The displacement of the current collector plate due to the deformation or displacement of the sealing member inside the case is suppressed, thereby stabilizing the connection state between the energy storage element and the external terminal.

[0020] (3) The internal resistance of the energy storage element due to deterioration of the connection between the energy storage element and the external terminals can be suppressed.

[0021] (4) By sandwiching both sides of the sealing member between the current collecting plate and the support member and pressing the sealing member by crimping, it is possible to prevent internal case pressure from acting on parts of the current collecting plate and the support member inside the case. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a diagram illustrating an example of the internal configuration of an electricity storage device according to a first embodiment. [Figure 2] FIG. 1 is a diagram illustrating an external appearance of an electricity storage device. [Figure 3] FIG. 2 is an exploded view illustrating a configuration example of the electricity storage device. [Figure 4] 10A and 10B are diagrams illustrating an example of a state of stress applied to a sealing member. [Figure 5] FIG. 10 is a diagram illustrating an example of a folder structure. [Figure 6] FIG. 2 is a diagram illustrating a configuration example of an energy storage element. [Figure 7] 10A and 10B are diagrams illustrating an example of forming an electrode tab. [Figure 8] FIG. 10 is a diagram showing a configuration example of an energy storage element on which a current collecting plate is installed. [Figure 9] FIG. 10 is a diagram illustrating an example of the internal configuration of an electricity storage device according to a second embodiment. [Figure 10] FIG. 10 is a diagram illustrating a modified example of the electricity storage device. DETAILED DESCRIPTION OF THE INVENTION

[0023] [First embodiment] Fig. 1 shows an example of the configuration of an electricity storage device according to the first embodiment. The configuration shown in Fig. 1 is an example, and the technology of the present disclosure is not limited to such a configuration.

[0024] As shown in FIG. 1 , the electricity storage device 2 is an example of an electric double layer capacitor, an electrolytic capacitor, or other electricity storage device, and includes a storage section 6 formed in an exterior case 4 and stores an electricity storage element 8, an electrolyte (not shown), and the like. The electricity storage device 2 is a device with a so-called axial structure, which uses an electricity storage element 8 formed, for example, by winding an electrode foil or the like into a cylindrical shape and having an anode tab 10 on one end surface and a cathode tab 12 on the other end surface. The electricity storage device 2 is arranged such that the anode tab 10 faces toward the opening of the case 4, and a current collector plate 14 is connected to part or all of the tip of the anode tab 10. The electricity storage device 2 also includes at least an external terminal 16, a sealing member 18, and a folder 20 within the storage section 6.

[0025] The current collector 14 is a current collector that electrically connects the wound electrode foil and the external terminal 16 and conducts the charge stored in the electrode foil on the anode side to the external terminal 16, and is made of, for example, a conductive metal material. This electricity storage device 2 uses a current collector 14 that is joined to the external terminal 16 formed from a separate member, or that is molded integrally with the external terminal 16 from the same material. The current collecting plate 14 is an example of a support plate of the present disclosure that contacts and supports the sealing member 18 arranged on the opening side within the storage section 6, and is arranged so that, for example, the same surface as the surface on which the external terminal 16 is formed contacts one surface of the sealing member 18. The external terminal 16 is an example of a first external terminal of the present disclosure, and functions as, for example, an anode terminal. The external terminal 16 has a diameter smaller than the outer shape or width of the current collector plate 14, and is formed at or near the center of the disk surface of the current collector plate 14. As a result, the current collector plate 14 and the external terminal 16 are arranged in an inverted "T" shape when housed in the exterior case 4.

[0026] In the electricity storage device 2, a sealing member 18 that seals the opening of the storage section 6 is disposed inside the storage section 6. The sealing member 18 is an example of a means for preventing foreign matter from entering the storage section 6 and also preventing leakage of the electrolyte inside the storage section 6, and is formed, for example, from insulating rubber, other rubber materials, or resin materials. The external terminals 16 protruding from the current collector plate 14 toward the opening are inserted into the sealing member 18, allowing the tip ends of the external terminals 16 to be positioned outside the exterior case 4. At this time, the sealing member 18 is in a crimped state against part of the circumferential surface of the external terminals 16, insulating them from each other.

[0027] The folder 20 is an example of a support member of the present disclosure that is positioned on the opening side within the storage section 6 to support the sealing member 18, and includes, for example, a support surface portion 22 that is positioned on the plane of the sealing member 18 to support it, and a protrusion portion 24 that is formed perpendicular to or nearly perpendicular to this support surface portion 22 and protrudes outward from the opening. Support surface portion 22 is formed, for example, on a plane facing the opening side of outer case 4, with an area that contacts a predetermined width on the outer edge side. This support surface portion 22 is in surface contact with at least sealing member 18, and is formed with a width that allows it to contact the tip or a portion close to it of vertical crimping portion 32 that crimps open edge 36 (FIG. 3) of outer case 4 toward the inside of storage section 6, and is located at a position that contacts vertical crimping portion 32.

[0028] The protrusion 24 is an example of a second external terminal of the present disclosure, and is used as a terminal component of the electricity storage device 2 by being inserted into a substrate (not shown) or the like. One or more protrusions 24 are formed on the folder 20, for example. In the electricity storage device 2, for example, the cathode tab 12 of the energy storage element 8 is connected to the bottom of the exterior case 4 directly or via a current collector (not shown). The exterior case 4 is formed, for example, partially or entirely from a conductive metal material, and the opening end 36 on which the vertical crimping portion 32 is formed is in contact with the support surface portion 22 at a contact point P. In this case, the opening end 36 is brought into strong contact with the support surface portion 22 by vertical crimping, for example, or the opening end 36 may be caused to bite into the support surface portion 22. This establishes electrical conduction between the protrusion 24 and the cathode tab 12 of the energy storage element 8 via the support surface portion 22, the contact point P, and the exterior case 4.

[0029] The protrusions 24 may be used as support terminals for stably holding the electricity storage device 2 mounted on a substrate or the like. In addition, when a plurality of protrusions 24 are formed, some of the protrusions 24 may be used as external terminals on the cathode side, and the rest may be used as support terminals.

[0030] Additionally, the electricity storage device 2 has a crimped portion 30 formed on the exterior case 4 in accordance with the position of the sealing member 18 inside the storage section 6. The crimped portion 30 is an example of a means for pressing the exterior case 4 with a predetermined pressure from the outside in the direction of the central axis, thereby crimping the inner wall surface of the exterior case 4 and the outer peripheral surface of the sealing member 18. In this crimping process, the pressing force is set based on, for example, the rigidity of the exterior case 4 and the sealing member 18, the expected depth of the crimped portion 30, and the like. The crimped portion 30 is formed, for example, by pressing a pressing jig (not shown) against the peripheral surface of the exterior case 4 and rotating either the jig or the electricity storage device 2, or both.

[0031] <External Configuration of Power Storage Device 2> 2, the power storage device 2 has an external terminal 16 arranged at the center of the opening of the exterior case 4, and a plurality of protrusions 24a, 24b, and 24c arranged around the external terminal 16. The power storage device 2 also has a vertical crimping portion 32 formed on the outer periphery, with the support surface 22 of the folder 20 exposed in the opening on the inner side, and a part of the sealing member 18 exposed further toward the center. Furthermore, a crimped portion 30 is formed on the side surface of the electricity storage device 2 along the periphery of the exterior case 4, for example, in accordance with the position where the sealing member 18 is disposed.

[0032] Note that, on the circumferential surface of outer case 4, for example, crimping portion 30 aligned with the position of sealing member 18 may be formed, as well as a crimping portion for crimping energy storage element 8 to the inner wall surface of outer case 4. In this case, for example, the wound electrode foil of energy storage element 8 may be entirely covered with an insulating material at least at the crimping position, to prevent electrical conduction between part of the circumferential surface of energy storage element 8 and the inner wall surface of outer case 4.

[0033] <Internal configuration of the electricity storage device 2 and its manufacturing process> Fig. 3 shows an example of the internal configuration of the power storage device. The configuration of the power storage device and the process of forming the power storage device shown in Fig. 3 are examples, and the present invention is not limited to these.

[0034] 3 , the electricity storage device 2 is housed in a storage section 6 of an exterior case 4 through an opening thereof, with the electricity storage element 8, current collecting plate 14, sealing member 18, folder 20, etc. housed therein. All or some of the electricity storage element 8, current collecting plate 14, sealing member 18, and folder 20 may be housed as a single unit by being in contact or connected before being housed in the case 4, or may be housed in contact or connected within the storage section 6. In the electricity storage device 2, the opening of the storage section 6 is sealed by arranging the sealing member 18 and the support surface section 22 of the folder 20 on one surface of the sealing member 18.

[0035] The exterior case 4 has, for example, an opening on one end side of the storage section 6 that is open to the outside, and is formed into a cylindrical shape with a bottom and a circular or polygonal cross section parallel to the opening. This exterior case 4 is made of a hard material that is corrosion-resistant and conductive against contact with the electrolyte filled inside and the outside air, and is flexible enough to be deformed by external crimping, such as a metal such as aluminum, as well as an aluminum alloy with added manganese or magnesium.

[0036] In exterior case 4, for example, an energy storage element 8 formed by winding an electrode foil into a cylindrical shape is stored with anode tab 10 facing the opening side and cathode tab 12 facing the bottom side, and current collector plate 14, sealing member 18, and folder 20 are placed on anode tab 10. Before energy storage element 8 is stored in storage section 6, for example, at least anode tab 10 and current collector plate 14 may be connected. Furthermore, when the cathode tab 12 is inserted into the storage section 6 of the outer case 4, it is brought into contact with the bottom, and then electrically connected by welding it to the bottom surface from the outside of the outer case 4.

[0037] The sealing member 18 is formed, for example, from insulating rubber, other rubber materials, or resin materials. The sealing member 18 has an outer diameter equivalent to the inner diameter of the storage section 6, and its outer shape is circular, elliptical, or polygonal, similar to the cross-sectional shape of the storage section 6. This improves the sealing performance of the sealing member 18 against the inner wall surface of the storage section 6, thereby improving the sealing performance of the opening. Furthermore, the sealing member 18 has an insertion hole 40, for example, at or near the center of the sealing surface, through which the external terminal 16 is inserted. The opening diameter of this insertion hole 40 is, for example, equivalent to the cross-sectional shape of the external terminal 16 and is formed to be the same as or smaller than the outer diameter thereof. This improves the adhesion between the sealing member 18 and the external terminal 16.

[0038] After the storage element 8, current collector plate 14, sealing member 18, and folder 20 are placed in storage section 6 together with an electrolyte solution (not shown), crimping section 30 is formed on the side surface on the opening side, and part of opening edge 36 of exterior case 4 is curled and pressed toward the inside of storage section 6 to form vertical crimping section 32 ( FIG. 1 ), thereby sealing the storage section 6. The crimping sections 30 and 32 may be formed in either order, or may be formed simultaneously. Additionally, the crimping process is performed, for example, by pressing with a predetermined force against the upper surface of sealing member 18 stored in storage section 6 and placing it in a predetermined position within storage section 6. The position when pressed is set using dimensional information such as the length of storage section 6, the length of at least the stored energy storage elements 8, the heights of anode tabs 10 and cathode tabs 12, the thickness of current collector plate 14, and the thickness of sealing member 18. Then, once crimped portions 30 and vertical crimped portions 32 are formed on exterior case 4, the pressure on sealing member 18 is released. This pressing process on sealing member 18 uses, for example, a dedicated jig that can contact only the upper surface of sealing member 18 without contacting external terminals 16 or folder 20.

[0039] <Regarding the sealing state of the opening of the storage section 6> FIG. 4 shows an example of the state of stress applied to the sealing member.

[0040] Within the storage compartment 6 of the electricity storage device 2, whose opening is sealed, for example, as shown in A of FIG. 4 , the crimping portion 30 and the vertical crimping portion 32 press the closure member 18 in a predetermined direction, and the circumferential surface is fixedly supported by the current collector plate 14 and the support surface portion 22 of the folder 20. Furthermore, in the electricity storage device 2, the crimping portion 30 and the vertical crimping portion 32 are formed with the closure member 18 pressed toward the interior of the storage compartment 6, and then the pressure on the closure member 18 is released. That is, for example, the closure member 18 is slightly displaced toward the electricity storage element 8 together with the current collector plate 14 due to the pressure. As a result, the electricity storage element 8, or the anode tab 10 or the cathode tab 12, is in a compressed state due to the displacement of the current collector plate 14 and the closure member 18. That is, the closure member 18 is brought into close contact with the inner wall surface of the exterior case 4 by the crimping portion 30, for example, and is thereby subjected to a predetermined pressing force FxA in the direction of the central axis of the electricity storage device 2. Furthermore, when the closing member 18 is subjected to the pressing force FxA, the stress acts toward the center through the body portion and is transmitted to the external terminal 16 through the inner wall surface of the insertion hole 40. That is, a pressing force FxB proportional to the pressing force FxA is generated on the inner wall surface of the insertion hole 40 of the closing member 18, and the circumferential surface of the external terminal 16 is supported by this pressing force FxB. As described above, since the external terminal 16 is formed integrally with the current collecting plate 14, the pressing force FxB acts as a holding force for positioning the current collecting plate 14 in a predetermined position.

[0041] In addition, a pressing force Fy from the vertical crimping portion 32 acts on the closure member 18 from the opening toward the bottom. The pressing force Fy acts on the flat portion of the closure member 18 from the support surface portion 22 of the folder 20 through the contact point P. In this way, predetermined pressing forces FxA and Fy are applied to the sealing member 18 in the direction of the central axis and inward of the storage section 6 by assembling the electricity storage device 2. Furthermore, sealing member 18 is crimped in a state displaced by the pressure and fixed at the displaced position, and is subjected to a repulsive force FR from energy storage element 8 or anode tab 10 or cathode tab 12 in a compressed state.

[0042] 4B, when the internal pressure in the storage unit 6 increases due to the operation of the electricity storage device 2, a pressure Fi acts on the sealing member 18 in the direction of the opening, either directly within the storage unit 6 or via the current collector plate 14. Such pressure Fi does not necessarily occur uniformly in the same direction throughout the storage unit 6. That is, the current collector plate 14 and the sealing member 18 may be subjected to a large pressure Fi only in part of their flat portions. Furthermore, the pressure Fi may act in a direction inclined at a predetermined angle to the opening direction.

[0043] In the storage compartment 6 to which such pressure Fi acts, in this electricity storage device 2, the peripheral surface of the sealing member 18 is in contact with the inner wall surface of the exterior case 4, and the sealing surface is in contact with the folder 20 and the current collector plate 14. Furthermore, a pressing force FxA is applied to the sealing member 18 from the peripheral surface in the central axis direction by the crimping portion 30, and a pressing force Fy is applied toward the interior of the storage compartment 6 by the vertical crimping portion 32, as well as a repulsive force FR from the energy storage element 8 or the anode tab 10. In addition, the current collector plate 14 is fixed and held at the bottom side of the sealing member 18 by a pressing force FxB acting on the external terminal 16 from the inner wall surface of the insertion hole 40. As a result, the sealing member 18 is fixed at the outer peripheral surface and both flat surfaces, thereby maintaining its outer shape against uneven pressure Fi within the storage compartment 6 and preventing it from moving toward the opening. Furthermore, in this electricity storage device 2, by suppressing deformation and displacement of the sealing member 18, it is possible to prevent the pressure Fi inside the storage section 6 from acting on the contact point P between the support surface portion 22 of the folder 20 and the vertical crimping portion 32, for example.

[0044] <Example of folder 20 configuration> FIG. 5 shows an example of the appearance of a folder.

[0045] The folder 20 is made of a metal that is conductive and easy to form, such as iron or aluminum. As shown in Fig. 5A, the folder 20 includes a support surface 22 that is circular in shape and formed with a predetermined width, and protrusions 24a, 24b, and 24c that are formed with a predetermined width inside the plane of the support surface 22 and protrude toward the center of the circle, together with a space 34. The space 34 is formed to provide insulation between the support surface portion 22, which is electrically connected to the cathode tab 12, and the external terminal 16 protruding toward the opening, as well as to reduce the weight of the folder 20. The opening area of ​​this space 34 is inversely proportional to the width of the support surface portion 22, and therefore affects the supportability of the flat surface of the closure member 18. That is, by reducing the opening area of ​​the space 34, the width of the support surface portion 22 becomes wider, making it possible to support a wider flat surface on the opening side of the closure member 18. This increases the support strength of the flat surface of the closure member 18 against the internal pressure within the storage section 6. The folder 20 may be formed by pouring a metal material into a mold (not shown), or by subjecting the flat surface of the disk member to metal processing to form the space 34 and the protrusions 24a, 24b, and 24c.

[0046] 5B, the folder 20 may be processed to raise the protrusions 24a, 24b, and 24c to any desired state during molding or assembly of the electricity storage device 2. In this folder 20, for example, the connection portions between the support surface portion 22 and the protrusions 24a, 24b, and 24c may be formed wider than the protrusions 24a, 24b, and 24c to maintain the strength of the protrusions 24a, 24b, and 24c when folded and to make it easier to grasp the bendability and folding positions.

[0047] <Configuration and manufacturing process of the energy storage element 8> 6 shows an example of the configuration of an energy storage element. The configuration of the energy storage element and the manufacturing process including its molding are examples. The content and procedure of the manufacturing process shown here are examples, and the present invention is not limited to such a configuration.

[0048] 6A, for example, this energy storage element 8 has anode extension 42, where only anode foil 46 (FIG. 7) protrudes from one end surface of the wound electrode foil, and cathode extension 44, where only cathode foil 47 (FIG. 7) protrudes from the other end surface, and these are formed to form anode tab 10 or cathode tab 12. Energy storage element 8 is a wound element formed by, for example, forming a laminate of anode foil 46 and cathode foil 47 with separator 48 (FIG. 7) interposed therebetween and winding this laminate in a predetermined direction to form a cylindrical shape. For example, aluminum foil is used as a base material for anode foil 46 and cathode foil 47, and polarizable electrodes containing an active material such as activated carbon and a binder are formed on both sides of this aluminum foil. Energy storage element 8 is formed by winding anode foil 46 and cathode foil 47 together with separator 48 in a stacked state, with winding center O as the reference. Before winding, anode foil 46 and cathode foil 47 have one long side portion extending in the winding direction protruding, and this long side portion is stacked during winding to form anode overhang 42 or cathode overhang 44.

[0049] Additionally, a retaining tape (not shown) may be wrapped around the periphery of energy storage element 8. This prevents the electrode foil from unwinding and also insulates energy storage element 8 from the inner wall surface of exterior case 4.

[0050] The end surface of energy storage element 8 is divided into a plurality of sections at predetermined angles in the circumferential direction of anode protrusion 42, for example, with winding center O as the reference. Anode protrusion 42 is formed by pressing a mold (not shown) against the element end surface for every other section, as shown in Fig. 6B, for example, to form first section 10A by bending anode protrusion 42 low and second section 10B by bending it so that it protrudes higher from the winding end surface than first section 10A. Furthermore, in energy storage element 8, first partition 12A and second partition 12B may be formed for cathode extension 44 in the same manner as for anode extension .

[0051] In the shaping process of the anode tab 10 and the cathode tab 12, for example, the anode overhang 42 or the cathode overhang 44 is folded to form the respective compartments 10A, 10B, 12A, and 12B, and then the shaping process is performed so that the height enables the anode tab 10 to be in close contact with the current collector plate 14 and the bottom of the storage section 6. As shown in Fig. 7A, for example, the first compartment 10A and the second compartment 10B, which have been creased using a mold or the like, are restored to an upright state by the elasticity of the anode foil. Similarly, in the cathode tab 12, the first partition 12A and the second partition 12B are in an upright state.

[0052] To stabilize the formed state of the anode tab 10 and the cathode tab 12, the anode tab 10 and the cathode tab 12 are formed in the energy storage element 8 by applying pressure from the tip side to the element end face side using a pressing jig 49, as shown in Fig. 7B, for example. By performing the forming process by applying pressure in this manner, the anode tab 10 and the cathode tab 12 can prevent the partition portions 10A, 10B, 12A, and 12B from rising up. Preventing the anode tab 10 and the cathode tab 12 from rising can increase the welding area and contact area with the current collector plate 14 and the bottom surface of the case. Furthermore, when the current collector plate 14 is displaced away from the anode tab 10 due to an increase in pressure inside the storage section 6, the anode tab 10 rises to a predetermined height by pressing the anode tab 10, and maintains that state. This prevents the anode tab 10 from breaking immediately when, for example, the pressure Fi begins to rise in the electricity storage device 2.

[0053] <Connection between energy storage element 8 and current collector plate 14> As shown in Fig. 8, for example, the connection surface of current collector plate 14 is placed on the anode tab 10 side of energy storage element 8. Then, current collector plate 14 is welded to anode tab 10 by, for example, irradiating laser light from the surface opposite to the connection surface. In the welding process, laser light is irradiated onto the position of second partition portion 10B formed on anode tab 10, and a weld 50 is formed. During the laser irradiation, the energy storage element 8 may be shielded using an inert gas such as argon gas or helium gas as a shielding gas to prevent the effects of laser heat and sputtering on the energy storage element 8. After storing the cathode tab 12 side of the energy storage element 8 in a storage section 6 (not shown), the bottom part may be irradiated with a laser from the outside of the exterior case 4 to perform welding processing.

[0054] [Effects of the first embodiment] According to this configuration, the following effects can be obtained.

[0055] (1) By covering the peripheral surface and the vertical flat surfaces of the sealing member 18 with the current collector 14, the folder 20, and the outer case 4, and clamping the sealing member 18 with the pressing forces FxA, Fy, and the repulsive force FR applied by the crimping portion 30 and the vertical crimping portion 32, deformation and displacement of the sealing member 18 due to an increase in the pressure Fi inside the storage section 6 can be suppressed.

[0056] (2) By suppressing deformation and displacement of sealing material 18, the connection state between energy storage elements 8 and external terminals 16 can be stabilized.

[0057] (3) An increase in the internal resistance of the electricity storage device 2 due to deformation or displacement of the sealing member 18 inside the storage section 6 can be suppressed.

[0058] (4) By preventing the sealing member 18 from being deformed or displaced, it is possible to prevent the internal pressure of the case from acting on the current collector plate 14 and a part of the holder 20 inside the outer case 4 .

[0059] (5) Even if excessive pressure acts between a part of the folder 20 and the crimped opening end 36 due to displacement of the closing member 18, damage to either or both of the folder 20 and the outer case 4 can be prevented.

[0060] (6) When a part of the folder 20 is used as an external terminal of the electricity storage device 2, it is possible to suppress an increase in the connection resistance of the terminal due to the pressure Fi acting on the folder 20 caused by deformation or displacement of the sealing member 18.

[0061] (7) By forming the crimping portion 30 and the vertical crimping portion 32 on the sealing member 18 while pressing it from the opening side toward the inside of the storage section 6, the sealing member 18 can be positioned at a set position within the storage section 6, and the stability of the product can be improved during the manufacturing process of the energy storage device 2.

[0062] (8) In the energy storage device 2 having the crimping portion 30 and the vertical crimping portion 32, a repulsive force FR is always applied to the sealing member 18 from inside the storage section 6 toward the opening, thereby stabilizing the clamping state of the sealing member 18 between the current collecting plate 14 and the folder 20 and improving the sealing function.

[0063] Second Embodiment Fig. 9 shows an example of the internal configuration of an electricity storage device according to the second embodiment. The configuration shown in Fig. 9 is an example, and the present invention is not limited to such content. In Fig. 9, the same parts as those in Fig. 1 are denoted by the same reference numerals.

[0064] 9, this electricity storage device 60 includes an anode external terminal 16 on the opening side of the exterior case 4 and a cathode external terminal 62 on the bottom side. That is, compared to the first embodiment, this electricity storage device 60 does not include a protrusion 24 and includes a folder 20 having at least an annular support surface portion 22. The external terminal 62 is an example of a second external terminal of the present disclosure, and may be formed integrally with the outer case 4 using the same material, or may be a separate member that can be electrically connected to the bottom 64 of the outer case 4. In the energy storage device 60, for example, when the energy storage element 8 is inserted into the storage section 6, the cathode tab 12 is brought into contact with the bottom 64 of the outer case 4, and then welding is performed from the outside of the outer case 4, thereby electrically connecting the cathode tab 12 and the external terminal 62.

[0065] Furthermore, for the anode tab 10 side of the energy storage element 8, for example, the current collector plate 14 and the anode tab 10 are welded together before being stored in the storage section 6, and then the external terminal 16 is inserted into the insertion hole 40 and positioned until the flat portion of the sealing member 18 contacts the current collector plate 14. Then, the folder 20 is placed on the flat portion of the sealing member 18. At this time, the folder 20 is positioned so that the central axis of the support surface portion 22 overlaps with, for example, the winding center O of the energy storage element 8 or the center of the external terminal 16 that has been previously installed. The steps following the installation of sealing member 18 may be performed after energy storage element 8 is placed in storage section 6.

[0066] The energy storage device 60 forms a crimping portion 30 on the peripheral surface of the outer case 4 in accordance with the position of the sealing member 18, and also forms a vertical crimping portion 32 by bending the opening end 36 of the outer case 4 toward the storage portion 6 and pressing it while contacting the support surface portion 22. As a result, inside the energy storage device 60, as already described, the peripheral surface and the flat surface in the vertical direction of the sealing member 18 are covered by the current collector plate 14, the folder 20, and the outer case 4, and the sealing member 18 is fixed and held in place by the pressing forces FxA, Fy from the crimping portion 30 and the vertical crimping portion 32, and the repulsive force FR from the energy storage element 8, the anode tab 10, the cathode tab 12, etc.

[0067] [Effects of the second embodiment] According to this configuration, the following effects can be obtained.

[0068] (1) The same effects as those of the first embodiment can be obtained.

[0069] (2) The sealing function of the sealing member 18 against internal pressure is improved, and by providing external terminals of different polarities on both ends, it is possible to provide an electricity storage device 60 that matches the specifications of the substrate on which it is mounted.

[0070] (3) By not using the outer surface of the outer case 4 as part of the external terminal or as a conductive component to the external terminal, the possibility of short circuits occurring due to contact of conductors or the like with the outer case 4 can be reduced when electronic components are densely mounted or while the energy storage device 60 is operating.

[0071] Other Embodiments Modifications of the above-described embodiment are listed below.

[0072] (1) In the above embodiment, the vertical crimping portion 32 contacts the open end 36 of the curled outer case 4 with the flat surface of the support surface 22 of the folder 20 or presses it into place with a pressing force Fy. However, this is not limited to this. In this electricity storage device 70, as shown in FIG. 10 , a groove 72 for engaging the open end 36 may be provided on a portion of the flat surface of the support surface 22. The groove 72 may be formed during the manufacturing process of the folder 20, or may be formed when the vertical crimping portion 32 is formed on the outer case 4, so as to correspond to the contact position with the open end 36. The groove 72 may be formed, for example, around the entire circumference of the annular support surface 22, or may be formed at predetermined intervals and with a predetermined length. In this case, the open end 36 of the outer case 4 may have protruding engagement portions formed at positions corresponding to the grooves 72 formed at predetermined intervals.

[0073] Providing such groove portion 72 enables the power storage device 70 to improve the connectivity between the folder 20 and the opening end 36 during the vertical crimping process. Furthermore, by engaging the opening end 36 with the groove portion 72, it is possible to prevent the pressing force Fy caused by the vertical crimping from dispersing in the horizontal direction of the support surface portion 22 due to the influence of the elastic force of the exterior case 4, etc., and it is possible to efficiently apply the pressing force Fy to the closure member 18.

[0074] (2) In the above embodiment, the protrusions 24a, 24b, and 24c are molded to protrude from the central axis of the disc surface, as shown in A of Fig. 5, but this is not limiting. For example, the protrusions 24a, 24b, and 24c may be molded to protrude obliquely from the central axis on the disc surface constituting the folder 20, and may be configured to rise vertically from the connection with the support surface 22. This molding process allows the protrusion length to be adjusted freely by changing the angle at which the protrusions 24a, 24b, and 24c are formed relative to the central axis without changing the outer diameter of the disc surface constituting the folder 20.

[0075] (3) In the above embodiment, a portion of the outer case 4 curls at the vertical crimping portion 32 formed on the opening side of the outer case 4, creating a predetermined gap on the outer periphery of the folder 20 placed in the storage section 6. In this modified example, for example, a portion of the closure member 18 deformed by the pressing force Fy due to the vertical crimping or the pressing force FxA due to the crimping of the crimping portion 30 may be configured to enter into the gap. In other words, in the electricity storage device according to this modified example, the gap created between the folder 20 and the vertical crimping portion 32 is sealed with a portion of the closure member 18. Furthermore, in the manufacturing process of the electricity storage device, the pressing force and pressing direction may be adjusted in the molding process of the crimped portion 30 and the vertical crimped portion 32 in order to deform the sealing member 18 and allow a portion of it to enter into such a gap.

[0076] According to this configuration, the sealing performance of the sealing member 18 with respect to the exterior case 4 can be improved.

[0077] (4) In the above embodiment, the support plate supporting the sealing member 18 is configured such that one surface of the current collector plate 14 opposite to the surface that contacts the energy storage element 8 is in contact with one surface on the bottom side of the sealing member 18. However, this is not limited to this. The storage section 6 of the energy storage device 2 may be provided with, for example, a support plate that is a separate component from the current collector plate 14 and supports the bottom side of the sealing member 18. That is, in the storage section 6, for example, the energy storage element 8, the anode tab 10, the current collector plate 14, the support plate, the sealing member 18, and the folder 20 are arranged, facing the opening side, and the sealing member 18 is sandwiched between at least the support plate and the folder 20. Furthermore, this support plate may be arranged, for example, so that the surface that is not in contact with sealing member 18 is in contact with the surface of current collector plate 14 on the opening side, or so that a space is provided between the support plate and current collector plate 14. The distance between the support plate and current collector plate 14 may be set, for example, based on simulation results that at least assume deformation or displacement of sealing member 18 due to internal pressure that increases during operation of electricity storage device 2. In the manufacturing process of electricity storage device 2, for example, after current collector plate 14 is connected to electricity storage element 8, a support plate may be placed on the flat surface of current collector plate 14, or sealing member 18 and the support plate may be integrated in advance and then stored in storage section 6. In addition, even when a support plate is used, the same process as the manufacturing method described above may be performed.

[0078] As explained above, the most preferred embodiment of the technology of the present disclosure has been described. The technology of the present disclosure is not limited to the above description. Various modifications and changes are possible for those skilled in the art based on the gist of the claims or disclosed in the description for carrying out the invention. It goes without saying that such modifications and changes are included within the scope of the technology of the present disclosure. [Industrial Applicability]

[0079] The disclosed energy storage device and its manufacturing method are useful because the peripheral surface and vertical flat surfaces of the sealing member are covered by the current collector plate, folder, and outer case, and are fixed and held in place by the pressing force exerted by crimping in the peripheral direction and vertical crimping inside the storage section, thereby suppressing deformation and displacement of the sealing member due to increased pressure inside the storage section and improving the sealing performance of the storage section. [Explanation of symbols]

[0080] 2, 60, 70 Energy storage devices 4. Outer case 6 Storage area 8. Energy storage element 10 Anode tab 10A, 12A First compartment 10B, 12B Second compartment 12 Cathode tab 14 Current collector plate 16, 62 external terminals 18 Sealing member 20 folders 22 Support surface part 24, 24a, 24b, 24c protrusion 30 Crimping part 32 Vertical crimping part 34 Space section 36 Open end 40 Insertion hole 42 Anode overhang 44 Cathode overhang 46 Anode foil 47 Cathode foil 48 Separator 49 Pressing jig 50 Welded Section 64 Bottom 72 Groove

Claims

1. a case having a storage section; an electric storage element having an electrode tab formed on a winding end surface and housed in the housing; a sealing member disposed within the storage portion, the sealing member having a peripheral surface that is crimped to an inner wall surface of the case by crimping from an outer periphery of the case, thereby sealing the opening of the storage portion; a support plate that contacts and supports a surface of the sealing member facing the bottom side of the storage portion; a support member that is disposed on a surface of the sealing member on the opening side of the storage portion, that presses and supports the sealing member by engaging with an open end of the case that is crimped toward the bottom side of the storage portion, and that includes a second external terminal that is electrically connected to the storage element via the case that is in contact with the electrode tab of the anode or cathode that is disposed on the bottom side of the storage portion; An electricity storage device comprising:

2. The power storage device according to claim 1 , wherein at least a portion of an outer edge of the bottom side surface and the opening side surface of the sealing member is sandwiched between the support plate and the support member.

3. the support plate is a current collector plate having one surface in contact with the electrode tab and the other surface in contact with the sealing member, and having a first external terminal on a part of the support plate; 3. The electricity storage device according to claim 1, wherein the sealing member has a through hole formed in a part of a sealing surface through which the first external terminal protruding from the current collector plate toward the opening, and the sealing member holds the current collector plate through the first external terminal by receiving stress due to crimping from the outer periphery of the case.

4. the electrode tabs include an anode tab formed on one winding end surface of the energy storage element and a cathode tab formed on the other winding end surface of the energy storage element, 4. The electricity storage device according to claim 1, wherein one of the anode tab and the cathode tab is welded to the support plate, and the other is fixedly connected to the bottom of the storage section by welding.

5. One surface of the current collector is brought into contact with an electrode tab formed on the winding end surface of the energy storage element, and the current collector is and a first external terminal integrated with the collector plate and electrically connecting the storage element to the first external terminal. The other surface is connected to one surface of a sealing member disposed in a housing portion of the case in which the electric storage element is housed. contacting; a step of placing a support member on a surface of the sealing member on the opening side of the storage portion; a step of crimping the outer periphery of the case to crimp the circumferential surface of the sealing member and the inner wall surface of the case to seal the opening; a step of crimping an open end of the case toward the current collecting plate, and pressing and supporting the sealing member by engagement between the open end and the support member; a step of electrically connecting the electrode tab of the anode or cathode arranged on the bottom side of the storage portion and a second external terminal formed on the support member to the energy storage element via the case; A method for manufacturing an electricity storage device, comprising:

6. further, pressing the sealing member stored in the storage section with a predetermined force to place the sealing member at a set position in the storage section; Including, The method for manufacturing an electricity storage device according to claim 5 , wherein the crimping process from the outer periphery of the case and the crimping process on the open end are performed in a state where the sealing member is pressed.

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