Electrochemical cell and method for manufacturing the same

Abstract

To make it possible to secure reliable sealing properties even when an outer package is made thin, which can lead to improvement of productivity as well.SOLUTION: An electrochemical cell includes: an exterior body 2 provided with a bottomed cylindrical container body 10 having a bottom wall 11 and a peripheral wall 12 and a sealing plate 20 that is welded to the container body and forms a storage space 5 relative to the container body; an electrode body 30 housed in the storage space; and a shim member 4 arranged in the storage space in a state of being pinched in a battery axis O direction between at least one member of the sealing plate and the bottom wall and the electrode body. The sealing plate is arranged so as to overlap with the bottom wall in the battery axis direction via the electrode body and the shim member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrochemical cell and a method for manufacturing an electrochemical cell. [Background technology]

[0002] Electrochemical cells such as lithium-ion secondary batteries and electrochemical capacitors have been widely used as power sources for small electronic devices and wearable devices, including wristwatches, smartwatches, smartphones, headsets, and hearing aids. In recent years, there has been an increasing demand for smaller and thinner electrochemical cells of this type. One reason for this is that, as the performance of various electronic devices incorporating electrochemical cells improves due to the miniaturization and reduced power consumption of integrated circuits (ICs), electronic devices equipped with unprecedented high-spec functions are beginning to be proposed.

[0003] In this type of electrochemical cell, for example, a metal case or a laminate film is known as an exterior body for housing the electrode assembly. A metal case typically comprises a cylindrical case body with a bottom and a sealing plate that seals the opening of the case body by crimping or the like via a resin gasket, and is often configured as a coin, button, cylindrical, or other shape overall.

[0004] In contrast, when a laminate film is used as the exterior body, it is possible to increase the degree of freedom in shape, which can easily lead to a reduction in size and an increase in capacity of the electrochemical cell itself. For example, Patent Document 1 below discloses an electrochemical cell including, as an exterior body, a first sheet formed of a laminate film into a cylindrical shape with a bottom, and a second sheet also formed of a laminate film into a cylindrical shape with a bottom and disposed inside the first sheet with an electrode assembly housed between the first sheet and the second sheet. The peripheral edges of the first sheet and the second sheet are welded together along their entire periphery via a ring-shaped sealant film. This seals the internal space housing the electrode assembly. The sealant film is formed by overlapping films made of a thermoplastic resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-126558 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, when a laminate film is used as an exterior body, as in the electrochemical cell described in Patent Document 1, the internal space containing the electrode body is sealed by welding (thermal welding) using a sealant film made of a thermoplastic resin. However, since the sealing is by welding of the resin, it is difficult to obtain sufficient sealing properties.

[0007] In contrast, when a metal case having a cylindrical case body with a bottom and a sealing plate is used as the exterior body, there is an advantage that a higher sealing performance can be obtained compared to when a laminate film is used. In particular, when the case body and the sealing plate are welded together by laser welding or the like instead of being fixed by caulking or the like, excellent sealing performance can be obtained. Furthermore, when the case body and the sealing plate are welded together, the mechanical strength required of the metal material can be reduced compared to when the case body and the sealing plate are secured by crimping, making it easier to make the metal material thinner. This allows the exterior body to be made thinner, which has the advantage of increasing the internal capacity.

[0008] However, if the thickness of the sealing plate is reduced, the sealing plate becomes more likely to bend, which reduces workability by making it more difficult to weld the case body and the sealing plate, etc. Furthermore, the bending or warping of the sealing plate makes it more likely that the sealing plate will become misaligned with respect to the case body, which could lead to poor welding and make it impossible to achieve sufficient sealing.

[0009] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an electrochemical cell and a method for manufacturing an electrochemical cell that can obtain reliable sealing even when the exterior body is made thin, and that can also lead to improved productivity. [Means for solving the problem]

[0010] (1) The electrochemical cell according to the present invention includes an exterior body including a container body having a bottom wall portion and a peripheral wall portion and formed into a bottomed cylindrical shape, a sealing plate welded to the container body so as to close an opening of the container body and forming a storage space between the container body and the sealing plate, an electrode body having a positive electrode and a negative electrode and accommodated in the storage space, and a shim member arranged in the storage space and sandwiched between the electrode body and at least one of the sealing plate and the bottom wall portion in the battery axis direction. a current collecting plate welded to the sealing plate or the bottom wall portion via an insulating seal material and at least a portion of which is exposed to the outside; the sealing plate is disposed so as to overlap the bottom wall portion in the battery axis direction via the electrode body and the shim member. One of the positive electrode and the negative electrode is electrically connected to the current collector plate, and the other electrode is electrically connected to the container body. The current collector plate is welded to the lower surface of the sealing plate facing the storage space via the sealing material, and is partially exposed to the outside through a through hole formed so as to penetrate the sealing plate in the battery axis direction. It is characterized by:

[0011] In the electrochemical cell according to the present invention, a shim member is accommodated in addition to the electrode assembly within the accommodation space. The shim member is arranged so as to be sandwiched in the battery axis direction between the electrode assembly and at least one of the sealing plate and the bottom wall portion. Therefore, the shim member can fill gaps formed between the electrode assembly and the sealing plate / bottom wall portion within the accommodation space. Therefore, when the sealing plate is combined with the container body during manufacturing of the electrochemical cell, the sealing plate can be positioned so as to overlap the bottom wall portion in the battery axis direction via the electrode assembly and the shim member, making it possible to support the sealing plate.

[0012] Therefore, even if the entire exterior body, including the sealing plate, is formed thin, unintended deformation, such as bending of the sealing plate, can be suppressed before welding the container body and the sealing plate. Therefore, welding can be performed while suppressing misalignment of the sealing plate relative to the container body, improving work efficiency and leading to improved productivity. Furthermore, the container body and the sealing plate can be precisely and appropriately welded, ensuring reliable sealing. Therefore, a high-quality electrochemical cell with high operational reliability can be obtained.

[0013] Furthermore, since it is only necessary to place a shim member inside the storage space, the space within the storage space can be used effectively, the size of the electrode assembly can be made as large as possible, and a wide variety of electrode assemblies can be applied without being limited to a specific structural type. This also leads to improved productivity, and it is possible to provide an electrode assembly that can be charged and discharged at a large current rate of 1 C (Capacity rate) or more in a short time (high-rate charge and discharge). Furthermore, since one of the positive and negative electrodes is electrically connected to the current collector plate and the other is electrically connected to the container body, the current collector plate and the container body can be used as external connection terminals, resulting in an electrochemical cell with excellent mountability. Furthermore, since the current collector plate can be disposed on the underside of the sealing plate, it is easy to establish electrical continuity between the current collector plate and one of the electrodes. Even in this case, the current collector plate can be partially exposed to the outside through the through-hole, allowing the current collector plate to function as an external connection terminal.

[0014] (2) The shim members may be disposed between the sealing plate and the electrode body, and between the bottom wall portion and the electrode body.

[0015] In this case, the gap between the sealing plate and the electrode body and the gap between the bottom wall and the electrode body can be filled with the shim member, and when the sealing plate is assembled to the container body, the electrode body and the shim member can be used to more stably support the sealing plate. This effectively prevents unintended deformation such as bending of the sealing plate, and allows welding work to be performed in a state where misalignment of the sealing plate with respect to the container body is further reduced.

[0016] (3) The shim member may be elastically deformable in the battery axis direction.

[0017] In this case, when the sealing plate is assembled to the container body, the shim member can be elastically deformed in the battery axial direction, so that the shim member can be used to appropriately fill the gap formed between the sealing plate and the bottom wall portion and the electrode body without having to adjust the thickness of the shim member in advance to accommodate the gap. Therefore, the electrode body and the shim member can be used to more stably support the sealing plate, and welding can be performed with further reduced positional deviation of the sealing plate relative to the container body.

[0018] (4) The shim member may be made of an insulating material.

[0019] In this case, there is no need to consider electrical conduction between the sealing plate, the container body, and the electrode body, and the shim member can be formed from, for example, an inorganic material such as ceramic or an insulating synthetic resin material. In particular, since there is no need to consider electrical conduction between the shim member and other components, the shim member can be designed with fewer restrictions, improving design freedom.

[0020] (5) The shim member may be made of a conductive material.

[0021] In this case, the shim member can be used as a conductor, so that at least one of the positive and negative electrodes of the electrode assembly can be electrically connected to the container or the like through the shim member. This makes it easy to reduce electrical resistance and improve battery performance. Furthermore, if the shim member is an elastically deformable conductor, it can absorb external shocks such as vibrations and maintain electrical connection, making it easy to maintain stable battery output.

[0028] ( 6 ) The battery may further include a support portion that is accommodated in the accommodation space along the battery axis direction and supports the sealing plate, and the electrode body may be wound around the central axis of the support portion in a state where the positive electrode and the negative electrode are stacked with a separator sandwiched between them.

[0029] In this case, in addition to supporting the sealing plate using the shim member, the sealing plate can also be supported using the support rods, which more effectively prevents unintended deformation such as bending of the sealing plate. This allows welding to be performed while further preventing misalignment of the sealing plate relative to the container body. Furthermore, the electrode body is a wound electrode wound around the central axis of the support rods. Therefore, after the electrode body is formed by winding, the electrode body together with the support rods can be housed in the container body. This allows for efficient assembly, leading to improved productivity.

[0030] ( 7 The electrode assembly may be formed by stacking the positive electrodes and the negative electrodes alternately in the axial direction of the battery with separators sandwiched therebetween.

[0031] In this case, the electrode assembly is a stacked electrode in which positive and negative electrodes are alternately stacked in the axial direction of the battery with a separator sandwiched between them, which makes it easier to ensure a large area between the positive and negative electrodes facing each other with the separator sandwiched between them, and makes it possible to produce an electrochemical cell with excellent charge / discharge characteristics that can be charged and discharged at a large current.

[0032] ( 8) A method for manufacturing an electrochemical cell according to the present invention includes an exterior body including a container body having a bottom wall portion and a peripheral wall portion and formed into a bottomed cylindrical shape, and a sealing plate welded to the container body so as to close an opening of the container body and forming a storage space between the container body and the sealing plate; an electrode body having a positive electrode and a negative electrode and housed in the storage space; and a shim member disposed in the storage space in a state sandwiched between the electrode body and at least one of the sealing plate and the bottom wall portion in the battery axis direction. a current collecting plate welded to the sealing plate or the bottom wall portion via an insulating seal material and at least a portion of which is exposed to the outside; A method for manufacturing an electrochemical cell comprising: a step of thermally welding a first sealant welded to the current collecting plate and a second sealant welded to the sealing plate to form the sealant consisting of the first sealant and the second sealant, and combining the current collecting plate and the sealing plate via the sealant; a step of combining at least one of the sealing plate and the bottom wall portion with the shim member; a step of setting the electrode assembly in the storage space inside the container body; and a step of combining the sealing plate with the container body so that the sealing plate is positioned so as to overlap the bottom wall portion in the battery axis direction via the electrode assembly and the shim member. a step of electrically connecting one of the positive electrode and the negative electrode to the current collector plate and electrically connecting the other electrode to the container body; and a step of welding the sealing plate to the container body.

[0033] According to the method for manufacturing an electrochemical cell of the present invention, when the sealing plate is combined with the container body, the gap formed between the sealing plate and the bottom wall and the electrode assembly within the storage space can be filled with a shim member. Therefore, the sealing plate can be positioned so as to overlap the bottom wall in the battery axis direction via the electrode assembly and the shim member, and the sealing plate can be supported. Therefore, even if the entire exterior body, including the sealing plate, is formed thin, unintended deformation, such as bending of the sealing plate, can be suppressed before welding the container body and the sealing plate. Therefore, welding can be performed while suppressing misalignment of the sealing plate relative to the container body, improving work efficiency and leading to improved productivity. Furthermore, the container body and the sealing plate can be precisely and appropriately welded, ensuring reliable sealing. Therefore, a high-quality electrochemical cell with high operational reliability can be obtained.

[0034] Furthermore, since it is only necessary to place a shim member inside the storage space, the space inside the storage space can be used effectively, the size of the electrode assembly can be made as large as possible, and a wide variety of electrode assemblies can be applied without being limited to a specific structural type. This also leads to improved productivity, and it is possible to provide an electrode assembly that can be charged and discharged at a large current rate of 1 C (Capacity rate) or more in a short time (high-rate charge and discharge). Furthermore, since one of the positive and negative electrodes is electrically connected to the current collector plate and the other is electrically connected to the container body, the current collector plate and the container body can be used as external connection terminals, resulting in an electrochemical cell with excellent mountability. In particular, since the sealant is constructed by thermally welding together the first sealant welded to the current collector plate and the second sealant welded to the sealing plate, the current collector plate and the sealing plate can be more firmly joined via the sealant.

[0035] ( 9 ) forming a through hole in the sealing plate in advance; after welding the container body and the sealing plate, injecting an electrolyte into the storage space through the through hole; and after injecting the electrolyte, closing the through hole.

[0036] In this case, the electrolyte can be poured after the container body and the sealing plate are welded together, which further improves productivity.

[0039] ( 10 After the current collecting plate and the first sealing material are overlapped, the current collecting plate may be heated by laser irradiation or induction heating, and the heat from the heated current collecting plate may be used to heat the first sealing material, thereby combining the current collecting plate and the first sealing material into one unit.

[0040] In this case, by heating the current collecting plate by, for example, laser irradiation, it is possible to heat it in a shorter time than by heater heating, etc., and the heat generated from the current collecting plate can be used to locally heat the first sealant, so it is possible to thermally weld the current collecting plate and the first sealant with a minimum amount of heat. Furthermore, when induction heating such as microwave irradiation is used, it is possible to selectively heat the current collecting plate, for example, and it is possible to thermally weld the current collecting plate and the first sealant while suppressing the thermal effects on the first sealant.

[0041] ( 11 After the sealing plate and the second sealant are overlapped, the current collector plate may be heated by laser irradiation or induction heating, and the heat from the heated current collector plate may be used to heat the second sealant, thereby combining the sealing plate and the second sealant into one unit.

[0042] In this case, by heating the current collector plate by, for example, laser irradiation, heating can be performed in a shorter time than by heater heating, etc., and the heat generated from the current collector plate can be used to locally heat the second sealant, making it possible to thermally weld the sealing plate and the second sealant with a minimum amount of heat. Furthermore, when induction heating such as microwave irradiation is used, it is possible to selectively heat the sealing plate, for example, and thermally weld the sealing plate and the second sealant while suppressing the thermal effects on the second sealant. [Effects of the Invention]

[0043] According to the present invention, an electrochemical cell can be obtained that can obtain reliable sealing even when the exterior body is made thin, and that can also lead to improved productivity. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a perspective view showing a first embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 2] 2 is a longitudinal cross-sectional view of the secondary battery taken along line AA shown in FIG. [Figure 3] FIG. 3 is a perspective view of the electrode body shown in FIG. [Figure 4] 4 is a longitudinal cross-sectional view of the electrode body taken along line BB shown in FIG. 3. [Figure 5] FIG. 3 is a perspective view of a first shim member shown in FIG. 2. [Figure 6] FIG. 10 is a diagram showing a modification of the first embodiment, and is a partially enlarged cross-sectional view showing a state in which the first shim member is set upside down. [Figure 7] FIG. 2 is a longitudinal sectional view showing a second embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 8] FIG. 8 is a perspective view of a first shim member shown in FIG. 7. [Figure 9] FIG. 10 is a longitudinal sectional view of a secondary battery showing a modified example of the second embodiment. [Figure 10] FIG. 3 is a longitudinal sectional view showing a third embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 11] 11 is a longitudinal cross-sectional view of the secondary battery taken along line CC shown in FIG. [Figure 12] FIG. 11 is a longitudinal sectional view of a secondary battery showing a modified example of the third embodiment. [Figure 13] FIG. 13 is a partially enlarged cross-sectional view of the container body shown in FIG. [Figure 14] FIG. 10 is a longitudinal sectional view showing a fourth embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 15] FIG. 10 is a vertical cross-sectional view showing a fifth embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 16] FIG. 10 is a longitudinal sectional view showing a sixth embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 17] FIG. 10 is a longitudinal sectional view showing a seventh embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 18] FIG. 10 is a longitudinal sectional view showing an eighth embodiment of a secondary battery (electrochemical cell) according to the present invention. [Figure 19] 19 is a diagram showing one process of winding the electrode body shown in FIG. 18 around a support rod, showing a state in which a separator has been fixed to the outer peripheral surface of the support rod. [Figure 20] 20 is a diagram showing a state in which the support column is rotated from the state shown in FIG. 19, and the separator is wound around the support column first. FIG. [Figure 21] FIG. 10 is a perspective view showing a modified example of the electrode body according to the present invention. [Figure 22] FIG. 22 is a perspective view of the combined state of the pair of positive and negative electrodes shown in FIG. 21, with the negative electrode facing upward. [Figure 23] FIG. 22 is an exploded view for explaining the combined state of a pair of positive and negative electrodes shown in FIG. 21. [Figure 24]FIG. 10 is a perspective view showing a modified example of the electrode body according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0045] (First embodiment) Hereinafter, an embodiment of an electrochemical cell according to the present invention will be described with reference to the drawings. In this embodiment, a lithium ion secondary battery (hereinafter simply referred to as a secondary battery), which is a type of non-aqueous electrolyte secondary battery, will be described as an example of the electrochemical cell.

[0046] As shown in Figures 1 and 2, the secondary battery 1 of this embodiment is a so-called button (coin) type battery, and includes a metal exterior body 2, and a power generating element 3 and a shim member 4 housed inside the exterior body 2.

[0047] The outer casing 2 comprises a metal container body 10 formed in a cylindrical shape with a bottom, and a metal lid member (sealing plate according to the present invention) 20 welded to the container body 10 so as to close the opening of the container body 10, forming a storage space 5 between the container body 10 and the lid member. The power generating element 3 includes an electrode body 30 having a positive electrode 40 and a negative electrode 50, and contains an electrolyte (electrolyte solution) not shown, and is housed in a housing space 5 formed inside the outer casing 2.

[0048] In this embodiment, the axis that passes through the center of the exterior body 2 and extends in the vertical direction is referred to as the battery axis O. In addition, in a plan view seen from the direction of the battery axis O, the direction that intersects with the battery axis O is referred to as the radial direction, and the direction that goes around the battery axis O is referred to as the circumferential direction. Furthermore, the direction from the bottom wall 11 of the container body 10 toward the lid member 20 along the battery axis O is referred to as the upward direction, and the opposite direction is referred to as the downward direction.

[0049] (exterior body) The exterior body 2 will now be described in detail. The container body 10 is formed in a cylindrical shape with a bottom, and includes a bottom wall portion 11 formed in a circular shape when viewed from above, and a peripheral wall portion 12 that is connected around the entire outer peripheral edge of the bottom wall portion 11 and extends upward from the bottom wall portion 11. However, the shape of the container body 10 is not limited to a cylindrical shape with a bottom, and may be formed so that the outer shape is, for example, elliptical, rectangular, or polygonal in plan view.

[0050] The container body 10 is made of metal and functions as an external connection terminal for a positive electrode or an external connection terminal for a negative electrode that is electrically connected to the electrode body 30. The container body 10 has a thickness of, for example, about 0.01 mm to 0.30 mm, making it a thin-walled metal container. However, in each drawing, the thickness of the container body 10 is exaggerated for ease of illustration.

[0051] The specific metal material of the container body 10 varies depending on whether the container body 10 is to function as an external connection terminal for a positive electrode or an external connection terminal for a negative electrode, but may be, for example, aluminum, aluminum alloy, copper, copper alloy, stainless steel, or a clad material (highly functional metal material) formed by pressure-bonding the same or different metals together, but is not limited to these. Examples of stainless steel include ferritic stainless steels such as SUS430 and SUS444, and austenitic-ferritic duplex stainless steels such as SUS329J4L.

[0052] Examples of clad materials include a three-layer clad material of Cu (inner layer) / Fe (middle layer) / Ni (outer layer), a three-layer clad material of Ni (inner layer) / Fe (middle layer) / Ni (outer layer), a three-layer clad material of Al (inner layer) / SUS (middle layer) / Ni (outer layer), etc. However, the clad material is not limited to three layers, and may be formed by pressure bonding other metals together in multiple layers.

[0053] When Cu is used as the clad material, the thermal conductivity can be increased, and therefore the heat dissipation during welding can be improved. Therefore, using Cu as the inner layer of the clad material is preferable because it can protect the electrode body 30.

[0054] Furthermore, it is preferable to form a metal plating film by plating either the inner surface or the outer surface of the clad material, or both the inner surface and the outer surface. Forming a metal plating film on the inner surface of the container body 10 can provide chemical stability and improve resistance to electrolytes, etc. Furthermore, forming a metal plating film on the outer surface of the container body 10 can provide functions such as rust prevention and reduce electrical resistance, thereby improving electrical connectivity with external terminals.

[0055] Specific examples of the metal plating film include Ni plating film and Ni alloy plating film, and it is particularly preferable to use an alloy plating film of a eutectic metal material. When an alloy plating film of a eutectic metal material is used, the melting point can be lowered when resistance welding is performed, and the welding temperature can be lowered. Other suitable materials include an Au-Ni alloy plating film, an Ni-P alloy plating film, and an Ni-B alloy plating film.

[0056] Furthermore, for example, when the secondary battery 1 of this embodiment is used in a watch, it is preferable that the metallic material of the container body 10 is non-magnetic in addition to being corrosion-resistant. Specific examples include aluminum, aluminum alloys, copper, and copper alloys as described above, as well as stainless steels such as various austenitic stainless steels such as SUS201, SUS202, SUS303, SUS304, SUS305, SUS316, SUS317, SUS321, and SUS347. Furthermore, the container 10 may be made of a material in which a resin layer is formed on the surface of any of the above-mentioned metals, such as a laminate film in which a metal layer made of stainless steel and a film-like resin layer are laminated together. In this case, the opening of the container 10 can be sealed by joining the metal lid member 20 and the metal layer of the container 10. For example, the resin layer may be made of the same resin material as that used for the sealant film 60 described below.

[0057] As shown in Figures 1 and 2, the lid member 20 is formed in the shape of a flat plate that faces the bottom wall portion 11 of the container body 10 in the direction of the battery axis O, sandwiching the electrode body 30 therebetween, and is welded and joined to the upper opening end of the peripheral wall portion 12 of the container body 10 in a state where it overlaps from above around the entire circumference. In the illustrated example, a step 20a is provided on the outer peripheral edge of the lid member 20 at a position overlapping the upper open end of the peripheral wall portion 12. As a result, the lid member 20 utilizes the step 20a to seal the storage space 5 with high airtightness.

[0058] The shape of the lid member 20 only needs to correspond to the shape of the container body 10, and may be formed so that the outer shape is, for example, elliptical, rectangular, or polygonal in plan view. The thickness of the lid member 20 is thin, for example, about 0.01 mm to 0.30 mm, similar to the container body 10. However, in FIG. 2, the thickness of the lid member 20 is exaggerated for ease of illustration. This also applies to the other drawings.

[0059] During assembly, the lid member 20 configured in this manner is placed on the upper opening edge of the peripheral wall portion 12 of the container body 10 from above, and then welded while applying pressure from above, for example. As a result, as described above, the peripheral wall portion 12 and the lid member 20 are firmly joined by welding around the entire periphery. This allows the lid member 20 to close the opening of the container body 10, and forms an accommodation space 5 (sealed space) between the lid member 20 and the container body 10 to accommodate the power generating element 3.

[0060] The method for welding the container body 10 and the lid member 20 is not particularly limited, but examples that can be used include resistance welding such as laser welding, ultrasonic welding, and seam welding, as well as friction stir welding (FSW). During these welding operations, the welding may be performed by a so-called workpiece movement method, in which the welding tool (not shown) is fixed and the exterior body 2, which is the work to be welded, is moved, or the welding may be performed by a so-called head movement method, in which the exterior body 2, which is the work to be welded, is fixed and the welding tool is moved.When laser welding is performed, a galvano scanning laser welder or the like can also be used.

[0061] In this embodiment, the lid member 20 is welded onto the upper opening edge of the peripheral wall portion 12 of the container body 10 from above, so it is preferable to use the galvano scanning method and laser welding in combination with the head movement method.

[0062] A through-hole 21 that passes through the lid member 20 in the vertical direction is formed in the center of the lid member 20 and is coaxial with the battery axis O. The shape of the through-hole 21 is not particularly limited, but is formed, for example, in a circular shape when viewed from above.

[0063] The lid member 20 configured as above is made of metal. As a specific metal material for the lid member 20, for example, the same type of metal as that of the container body 10 or a different type of metal material can be used. When a different type of metal material from that of the container body 10 is used as the metal material for the lid member 20, it is preferable to use a material with a thermal expansion coefficient similar to that of the container body 10. Furthermore, it is preferable to form a metal plating film on either the inner surface or the outer surface, or both the inner surface and the outer surface, of the lid member 20, similarly to the container body 10. As the metal plating film, the metal plating film described above can be used.

[0064] (current collector plate) The lid member 20 configured as described above is provided with a current collector plate 61, at least a portion of which is exposed to the outside (upward), and is heat-sealed (welded) via a sealant film (an insulating sealing material according to the present invention) 60, as shown in Figures 1 and 2. Specifically, the sealant film 60 and the current collecting plate 61 are disposed on the upper surface of the lid member 20 facing away from the storage space 5 in the direction of the battery axis O. The current collecting plate 61 is heat-welded to the upper surface of the lid member 20 via the sealant film 60, and is exposed upward over its entire surface.

[0065] The sealant film 60 is formed in a ring shape surrounding the through-hole 21 formed in the lid member 20, and is arranged so as to overlap the upper surface of the lid member 20 while being coaxial with the battery axis O. In the illustrated example, the sealant film 60 is formed with an inner diameter smaller than the diameter of the through-hole 21. However, this is not limited to this, and the inner diameter of the sealant film 60 may be formed to be equal to or larger than the diameter of the through-hole 21.

[0066] Furthermore, the sealant film 60 is formed so as to be folded downward from the inner peripheral edge portion, and is provided with a protective portion 60a that seals the entire inner peripheral surface of the through hole 21 of the lid member 20 from the inside in the radial direction. This is preferable because it is possible to prevent unintended conduction (short circuit) from the inside of the through hole 21 to the lid member 20.

[0067] The sealant film 60 is made of, for example, a thermoplastic resin such as polyolefin, or an engineering plastic such as polyphenylene sulfide (PPS). Examples of polyolefin include polyethylene, polypropylene, and polybutene. Furthermore, a copolymer or blend polymer of each of the above-mentioned polyolefins, or a composite such as polypropylene reinforced with nonwoven fabric may also be used as the sealant film 60. Furthermore, a plurality of sealant films 60 with different dimensions, shapes, or thicknesses may be stacked and used.

[0068] Furthermore, it is preferable to use a fluorine-based resin for the sealant film 60. Specific examples of the fluorine-based resin include FEP (perfluoroethylene propene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer resin), ETFE (ethylene tetrafluoroethylene copolymer, tetrafluoroethylene-ethylene copolymer resin), and PFA (perfluoroalkoxyalkane, tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin).

[0069] Generally, fluororesin has a high melting point and therefore has high heat resistance. Therefore, when a fluororesin sealant film 60 is used, the effect of welding heat on the sealant film 60 can be suppressed when the container body 10 and the lid member 20 are welded together (heat-sealed). Furthermore, fluororesin is a resin that has high chemical resistance and high density, so even when the sealant film 60 is made of fluororesin, it can still provide sufficient sealing properties as a sealant film 60. Furthermore, fluororesin has the property of having a small coefficient of linear expansion. Therefore, when the sealant film 60 is made of fluororesin, it is less likely to expand thermally when the container body 10 and the lid member 20 are welded together, and in this respect, it also has excellent sealing properties.

[0070] In the case of a fluorine-based resin sealant film 60, the melting point tends to be preferably within a temperature range of, for example, 260°C to 270°C in terms of processability during fusion. In terms of deterioration characteristics during storage, the lower the water absorption rate, the more preferable. Furthermore, in terms of resistance to temperature changes, the lower the linear expansion coefficient, the more preferable. Therefore, when using a fluorine-based resin sealant film 60, it is advisable to appropriately select a specific material (FEP, ETFE, PFA) in consideration of the melting point, water absorption rate, linear expansion coefficient, and other physical properties.

[0071] The current collecting plate 61 is a metal plate that functions as an external connection terminal for a positive electrode or an external connection terminal for a negative electrode that is electrically connected to the electrode body 30. In the illustrated example, the current collecting plate 61 is formed in a circular shape in a plan view with a diameter smaller than the outer diameter of the sealant film 60, and is arranged so as to overlap the upper surface of the sealant film 60 while being coaxial with the battery axis O. In this way, the current collecting plate 61 blocks the through-hole 21 from above.

[0072] The material of the current collector plate 61 is not particularly limited, but nickel, for example, can be suitably used. Furthermore, a metal made of a highly conductive material such as gold or nickel, or an alloy plating film containing these metals may be formed on the surface of the current collector plate 61 that can be connected to the outside.

[0073] The above-mentioned sealant film 60 is heat-welded to the upper surface of the lid member 20 and the lower surface of the current collector plate 61. Specifically, the sealant film 60 is formed by heat-welding together a first sealant made of synthetic resin that is integrally combined with the lower surface of the current collector plate 61 by heat welding, and a second sealant made of synthetic resin that is integrally combined with the upper surface of the lid member 20 by heat welding. As a result, the current collector plate 61 is heat-welded to the upper surface of the lid member 20 via the sealant film 60, and the through-hole 21 is airtightly sealed from above while maintaining insulation between the current collector plate 61 and the lid member 20.

[0074] It should be noted that the present invention is not limited to the use of the first and second sealing materials described above, and for example, the sealant film 60 may be directly heat-welded to the lid member 20 and the current collector plate 61 . In particular, when the current collecting plate 61 is heat-sealed to the lid member 20 using a fluorine-based resin sealant film 60, fluorine-based resin tends to have difficulty absorbing electromagnetic waves, so it is preferable to inductively heat the current collecting plate 61 side rather than directly heating (dielectric heating) the sealant film 60 side. In this case, in order to avoid localized discharge and reflection of electrons, it is preferable to increase the surface roughness of the current collecting plate 61 rather than making it smooth. In this case, it is acceptable to increase the surface roughness of at least the portion of the surface of the current collecting plate 61 where the sealant film 60 is heat-sealed, but it is preferable to increase the surface roughness of the entire current collecting plate 61. Furthermore, as a method for avoiding localized discharge and reflection of electrons, as mentioned above, it is preferable to form the current collector plate 61 into a shape with a smooth surface and no edges, and in addition to increasing the surface roughness as described above, the following method is also effective. That is, it is also effective to remove the corners of the current collector plate 61 by C-chamfering using press working or forging, or by filleting.

[0075] The sealant film 60 insulates the current collector 61 from the container 10. Therefore, the secondary battery 1 of this embodiment can be electrically connected to either the positive or negative terminal of the electronic device by bringing the current collector 61 and the container 10 into contact with a pressure terminal, a holder, or the like of the electronic device (not shown). Alternatively, a metal terminal may be further welded to at least one of the current collector 61 and the container 10, and then electrically connected to the electronic device by soldering, welding, or the like.

[0076] (power generation element) The power generating element 3 shown in FIG. 2 includes an electrode assembly 30 and an electrolyte solution (not shown), and is housed in a sealed state in a housing space 5 inside the exterior housing 2. The electrolyte may be, for example, a liquid in which a supporting salt is dissolved in an aprotic, non-aqueous solvent. The supporting salt may be, for example, lithium fluorophosphate (LiPF6). The solvent may be, for example, ethylene carbonate (EC) and a low-boiling-point solvent.

[0077] However, the power generating element 3 may employ an electrode assembly 30 that uses an electrolyte such as a solid electrolyte, a polymer electrolyte, or a gel electrolyte instead of an electrolytic solution. Examples of polymer electrolytes include polyethylene oxide (PEO), polypropylene oxide (PPO), blend polymers containing these, polyacrylic acid ester, polymethacrylic acid ester, polysiloxane, and polyphosphazene. Alternatively, a gel electrolyte containing poly(vinylidene fluoride-co-hexafluoropropylene, PVdF-HFP) may be used as the electrolytic solution.

[0078] (electrode body) 3 and 4, the electrode assembly 30 is a so-called laminated electrode in which positive electrodes 40 and negative electrodes 50 are alternately laminated in the direction of the battery axis O with separators (not shown) sandwiched between them, for example, by flatly winding them. Note that the illustration of the electrode assembly 30 is simplified in FIG. 2. The electrode body 30 is formed so that its outer shape is circular in plan view, but the outer shape of the electrode body 30 is not limited to this case and may be other shapes such as an ellipse, an oval shape, or a diamond shape, and may be changed as appropriate.

[0079] In this embodiment, the positive electrode 40 and the negative electrode 50 are alternately stacked by being wound with a separator sandwiched therebetween. However, this is not limited to this, and for example, the positive electrode 40 and the negative electrode 50 may be alternately stacked by being folded in a zigzag shape from directions that intersect with each other. Furthermore, a so-called pellet-type electrode body having the positive electrode 40 and the negative electrode 50 on both sides of the separator may also be used.

[0080] The structure of the electrode body 30 will now be briefly described. The positive electrode 40 includes a positive electrode current collector (positive electrode current collector foil) 41 formed in a strip shape in the unfolded state before being wound, and a positive electrode active material layer (not shown) formed on both sides of the positive electrode current collector 41.

[0081] The positive electrode current collector 41 is formed in the form of a thin sheet (metal foil) made of a metal material such as aluminum, aluminum alloy, or stainless steel, and includes a plurality of positive electrode bodies 42 and a plurality of positive electrode connection pieces 43. The thickness of the positive electrode current collector 41 is, for example, about several μm to 10 and several μm. In addition to metal foil, the positive electrode current collector 41 may be made of, for example, etched foil, embossed foil (textured), punched metal (through-hole processed), expanded metal, sintered metal, or metal foam. The positive electrode bodies 42 are formed, for example, in a disk shape and are arranged at intervals so as to be aligned in a row in the unfolded state before winding. The positive electrode connection pieces 43 are arranged between adjacent positive electrode bodies 42 in the unfolded state before winding, and connect the adjacent positive electrode bodies 42 to each other. Of the multiple positive electrode bodies 42, a positive electrode terminal tab 44 is formed on the positive electrode body 42 that is arranged on the outermost periphery in the wound state.

[0082] The positive electrode active material layer is formed on both surfaces of the positive electrode current collector 41 excluding the positive electrode terminal tab 44. As a material for forming the positive electrode active material layer, a positive electrode slurry can be prepared by mixing a positive electrode active material with a conductive additive (e.g., carbon black, graphite, etc.), a binder (e.g., polyvinylidene fluoride, etc.), and a solvent (e.g., any solvent such as N-methylpyrrolidone). Note that a coating liquid containing the constituent materials for forming the positive electrode active material layer can be referred to as a "positive electrode slurry." The positive electrode active material layer can be formed by applying this positive electrode slurry to the positive electrode current collector 41 and drying it. Examples of the positive electrode active material include composite oxides containing lithium and transition metals, such as nickel-manganese-cobalt lithium oxide (NMC), nickel-cobalt lithium aluminum oxide (NCA), lithium titanate (LTO), and lithium manganese oxide (LMO).

[0083] The negative electrode 50 includes a negative electrode current collector (negative electrode current collector foil) 51 formed in a strip shape in the unfolded state before being wound, and a negative electrode active material layer (not shown) formed on both sides of the negative electrode current collector 51.

[0084] The negative electrode current collector 51 is formed in the form of a thin sheet (metal foil) made of a metal material such as copper, copper alloy, nickel, or stainless steel, and includes a plurality of negative electrode bodies 52 and a plurality of negative electrode connection pieces 53. The thickness of the negative electrode current collector 51 is, for example, about several μm to 10 and several μm. In addition to metal foil, the negative electrode current collector 51 can be made of, for example, etched foil, embossed foil (textured), punched metal (through-holes), expanded metal, sintered metal, or foamed metal. The negative electrode bodies 52 are formed, for example, in a disk shape, similar to the positive electrode bodies 42, and are arranged at intervals in the unfolded state before winding. The negative electrode connecting pieces 53 are arranged between adjacent negative electrode bodies 52 in the unfolded state before winding, and connect the adjacent negative electrode bodies 52 to each other. Of the multiple negative electrode bodies 52, a negative electrode terminal tab 54 is formed on the negative electrode body 52 that is arranged on the outermost periphery in the wound state.

[0085] The negative electrode 50 has an outer shape similar to that of the positive electrode 40 described above. However, the outer size of the positive electrode 40 is formed to be slightly smaller (slightly smaller) than that of the negative electrode 50. Specifically, the outer diameter of the positive electrode 40 is preferably equal to or greater than the thickness of the positive electrode 40 and smaller than that of the negative electrode 50. For example, the outer size of the positive electrode 40 is preferably smaller than that of the negative electrode 50 by 20 μm or more, and more preferably by 50 μm or more.

[0086] The negative electrode active material layer is formed on both surfaces of the negative electrode current collector 51, excluding the negative electrode terminal tab 54. The negative electrode active material layer can be formed by mixing a negative electrode active material with a conductive additive (e.g., carbon black, graphite, etc.), a binder (e.g., a dispersion of styrene-butadiene rubber (SBR)), a thickener (e.g., cellulose nanofiber (CNF), carboxymethyl cellulose (CMC), etc.), and a solvent (e.g., any solvent such as pure water) to form a negative electrode slurry. A coating liquid containing the constituent materials for forming the negative electrode active material layer can be referred to as a "negative electrode slurry." The negative electrode active material layer can be formed by applying the negative electrode slurry to the negative electrode current collector 51 and drying it. Examples of the negative electrode active material include silicon, silicon oxide, graphite, hard carbon, lithium titanate (LTO), LiAl, and the like, either singly or in mixture.

[0087] The positive electrode 40 and negative electrode 50 configured as described above are wound with the separator sandwiched therebetween, and are stacked alternately. Then, in the electrode assembly 30 obtained by winding, as shown in Figures 3 and 4, the positive electrode main body 42 on which the positive electrode terminal tab 44 is formed is located at the bottom, and the negative electrode main body 52 on which the negative electrode terminal tab 54 is formed is located at the top. Therefore, the electrode assembly 30 is housed in the exterior body 2 in a state where the positive electrode terminal tab 44 faces downward and the negative electrode terminal tab 54 faces upward.

[0088] The separator is formed of, for example, a microporous film made of a resin such as polyolefin, a nonwoven fabric made of glass or resin, a laminate of fibers such as cellulose fibers, etc., and is capable of passing lithium ions through ion permeable pores (not shown). Further, as the separator, for example, a porous body capable of retaining an electrolyte solution in the pores, a resin layer having lithium ion conductivity, etc. can be used.

[0089] Furthermore, in the electrode body 30, one of the positive electrode 40 and the negative electrode 50 is electrically connected to the current collector plate 61, and the other electrode is electrically connected to the container body 10. Examples of the electrical connection include contact via a carbon-based material, welding of metals together, or contact of metals together.

[0090] In this embodiment, the negative electrode 50 is electrically connected to the current collector 61, and the positive electrode 40 is electrically connected to the container body 10. This allows the current collector 61 to function as an external connection terminal for the negative electrode, and the container body 10 to function as an external connection terminal for the positive electrode. However, this is not limited to this case, and the negative electrode 50 may be electrically connected to the container body 10, thereby making the container body 10 function as an external connection terminal for the negative electrode, and the positive electrode 40 may be electrically connected to the current collector 61, thereby making the current collector 61 function as an external connection terminal for the positive electrode.

[0091] When electrically connecting the negative electrode 50 to the current collector 61, for example, the negative terminal tab 54 may be electrically connected directly to the current collector 61 through the through hole 21 of the lid member 20 and the through hole 73 of the first shim member 71 described later, or the negative terminal tab 54 may be electrically connected to the current collector 61 by placing a conductor corresponding to a lead wire (not shown) connecting the negative terminal tab 54 to the current collector 61 inside the through holes 21, 73. Similarly, when conducting the positive electrode 40 to the container body 10, for example, the positive electrode terminal tab 44 may be electrically connected directly to the container body 10, or the positive electrode terminal tab 44 and the container body 10 may be electrically connected via a conductor equivalent to a lead wire (not shown). Furthermore, the negative electrode terminal tab 54 may be conducted to the container body 10 through a second shim member 80 (described later). In this case, the second shim member 80 may be formed of a conductive material.

[0092] (shim material) As shown in Figure 2, within the storage space 5 of the exterior body 2, a shim member 4 is arranged in a state where it is sandwiched between at least one of the lid member 20 and the bottom wall portion 11 and the electrode body 30 in the direction of the battery axis O. In this embodiment, the shim members 4 are disposed between the lid member 20 and the electrode body 30, and between the bottom wall portion 11 and the electrode body 30. As a result, the lid member 20 is disposed so as to overlap the bottom wall portion 11 in the direction of the battery axis O via the electrode body 30 and the two shim members 4.

[0093] Of the shim members 4, the shim member 4 arranged between the lid member 20 and the electrode body 30 is referred to as the first shim member 70, and the shim member 4 arranged between the bottom wall portion 11 and the electrode body 30 is referred to as the second shim member 80. The first shim member 70 and the second shim member 80 are members that fill the gap formed between the lid member 20 and the electrode body 30 and the gap formed between the bottom wall portion 11 and the electrode body 30, and are formed in a roughly plate shape. However, the shape, material, etc. of the shim members 4 (the first shim member 70 and the second shim member 80) are not particularly limited and may be changed as appropriate.

[0094] For example, the shim member 4 may be made of a conductive material or an insulating material. When the shim member 4 is made of a conductive material, it can be formed from, for example, carbon felt, carbon cloth, metal foam, conductive resin, etc., and specifically, metal mesh, metal springs, etc. are possible. In particular, when the shim member 4 is made of a conductive material, it is preferable to form it from a material with good electrical conductivity, such as gold or nickel. Furthermore, as the conductive resin, a thermosetting resin such as a phenolic resin or epoxy resin containing carbon such as CNT, graphene, graphite, or carbon black can be used. These thermosetting resins can be formed by applying them in a paste form and then solidifying them.

[0095] When the shim member 4 is formed from an insulating material, it is possible to use, for example, a glass mat, a glass fiber mat, a ceramic mat, a ceramic fiber mat, a paper mat, a cellulose fiber mat, a thermoplastic resin mat, a foam mat, a fibrous mat, a microporous PMF film, etc. In particular, when an engineering plastic thermoplastic resin is used as the thermoplastic resin, the resin may be formed by gluing or welding using a binder. Furthermore, the shim member 4 may be formed in a porous (sponge-like) shape with numerous holes (including through holes and blind holes), for example.

[0096] In this embodiment, as shown in FIGS. 2 and 5, the first shim member 70 is formed in the shape of a downwardly recessed circular plate in plan view, and is disposed coaxially with the battery axis O. Specifically, the first shim member 70 comprises a shim plate 71 having a circular shape in a plan view and arranged so as to overlap the electrode body 30 from above, and a bent portion 72 that is connected around the entire outer edge of the shim plate 71 and is bent while curving upward.

[0097] A through-hole 73 is formed in the center of the shim plate 71, penetrating the shim plate 71 from top to bottom. The through-hole 73 is formed in a circular shape in a plan view, and is disposed coaxially with the battery axis O. As a result, the shim plate 71 is formed in a ring shape. The diameter of the through hole 73 is, for example, the same as the diameter of the through hole 21 formed in the lid member 20. However, the diameter of the through hole 73 may be changed as appropriate regardless of the size of the through hole 21 formed in the lid member 20. The shape of the through hole 73 may be, for example, rectangular or polygonal in plan view. The position where the through hole 73 is formed may be shifted radially from the battery axis O.

[0098] The upper edge of the bent portion 72 contacts the lid member 20 from below. As a result, the first shim member 70 is disposed in a sandwiched state between the electrode body 30 and the lid member 20 so as to fill the gap between the electrode body 30 and the lid member 20. Furthermore, in this embodiment, the first shim member 70 is formed with a diameter such that the bent portion 72 abuts against the peripheral wall portion 12 of the container body 10 from the radially inner side or close to the peripheral wall portion 12. However, the diameter of the first shim member 70 is not limited to this case, and may be formed smaller than the outer diameter of the electrode body 30, for example.

[0099] 2, the second shim member 80 is formed in a disk shape in plan view with a diameter slightly smaller than the outer diameter of the electrode body 30, and is disposed coaxially with the battery axis O. However, the diameter of the second shim member 80 is not limited to this case and may be changed as appropriate. Furthermore, the shape of the second shim member 80 may be, for example, rectangular or polygonal in plan view, and may be changed as appropriate. The second shim member 80 is disposed in a state sandwiched between the electrode body 30 and the bottom wall portion 11 so as to fill the gap between the electrode body 30 and the bottom wall portion 11. The second shim member 80 may be disposed so as to overlap the bottom wall portion 11, or may be fixed integrally to the bottom wall portion 11.

[0100] (Action of secondary batteries) According to the secondary battery 1 configured as described above, as shown in Figures 1 and 2, the current collector 61 functioning as an external connection terminal for the negative electrode is exposed to the outside, and the container body 10 functioning as an external connection terminal for the positive electrode is exposed to the outside, so that the secondary battery 1 can be used by utilizing the current collector 61 and the container body 10.

[0101] In particular, according to the secondary battery 1 of this embodiment, as shown in Fig. 2, in addition to the electrode assembly 30, a first shim member 70 and a second shim member 80 are accommodated in the accommodation space 5. The first shim member 70 is disposed so as to be sandwiched between the lid member 20 and the electrode assembly 30 in the direction of the battery axis O, and fills the gap formed between the lid member 20 and the electrode assembly 30. The second shim member 80 is disposed so as to be sandwiched between the bottom wall portion 11 and the electrode assembly 30 in the direction of the battery axis O, and fills the gap formed between the bottom wall portion 11 and the electrode assembly 30.

[0102] Therefore, when the secondary battery 1 is manufactured, when the lid member 20 is combined with the container body 10, the lid member 20 can be positioned so as to overlap the bottom wall portion 11 in the direction of the battery axis O via the electrode body 30, the first shim member 70 and the second shim member 80, and the lid member 20 can be supported.

[0103] Therefore, even if the entire exterior body 2 including the lid member 20 is formed to be thin, unintended deformation such as bending of the lid member 20 can be suppressed before welding the container body 10 and the lid member 20 together. Therefore, welding can be performed while suppressing misalignment of the lid member 20 relative to the container body 10, improving work efficiency and leading to improved productivity. Furthermore, the container body 10 and the lid member 20 can be precisely and appropriately welded, ensuring reliable sealing. Therefore, a high-quality secondary battery 1 with high operational reliability can be obtained.

[0104] Furthermore, since the first shim member 70 and the second shim member 80 are simply placed within the storage space 5, the space within the storage space 5 can be utilized effectively, the size of the electrode body 30 can be made as large as possible, and a wide variety of electrode bodies 30 can be applied without being limited to a specific structural type. In particular, in this embodiment, the electrode assembly 30 is a flat, wound, laminated electrode, and it is easy to ensure a large area between the positive electrode 40 and the negative electrode 50 that face each other with the separator in between, so that charging and discharging (high-rate charging and discharging) can be performed at a large current rate of, for example, 1 C (Capacity rate) or more in a short time, thereby providing a secondary battery 1 with excellent charging and discharging characteristics.

[0105] As described above, according to the secondary battery 1 of this embodiment, even if the exterior body 2 is made thin, reliable sealing can be obtained, and this can lead to improved productivity. In particular, two shim members 4 (a first shim member 70 and a second shim member 80) are arranged in the accommodation space 5 to fill the gap between the lid member 20 and the electrode body 30 and the gap between the bottom wall portion 11 and the electrode body 30, thereby more stably supporting the lid member 20. Therefore, unintended deformation such as bending of the lid member 20 can be effectively suppressed, and welding work can be performed in a state where positional deviation of the lid member 20 relative to the container body 10 is further suppressed.

[0106] Furthermore, since the current collector 61 is disposed on the upper surface of the lid member 20, the current collector 61 can be exposed over the entire surface. Therefore, the current collector 61 can be effectively used as an external connection terminal for the negative electrode, making the secondary battery 1 easy to use and excellent in mountability.

[0107] Furthermore, in the secondary battery 1 of this embodiment, if the container body 10 and the lid member 20 are formed from the clad material described above, or if the container body 10 and the lid member 20 are plated, for example, when the secondary battery 1 generates heat due to some factor and the internal pressure rises, it is possible to take fail-safe measures such as peeling off the metal interface to release the internal pressure to the outside.

[0108] Furthermore, if the clad material is made of metals with different thermal expansion coefficients, when the desired temperature is reached, it will deform due to the heat alone at that temperature, thereby achieving the above-mentioned fail-safe function. Materials with a low thermal expansion coefficient can be, for example, Co-based alloys or Ni-based alloys, which are used as spring materials for watches. In this case, a clad material can be used in which a material with a high thermal expansion coefficient is used on the inner side of the battery and a material with a low thermal expansion coefficient is placed on the outer side. Furthermore, to reduce surface contact resistance, nickel or other plating can be applied to the surface of the metal with the low thermal expansion coefficient (outer side).

[0109] In this embodiment, the shim members 4 (the first shim member 70 and the second shim member 80) may be made of an insulating material or a conductive material. If the shim member 4 is made of an insulating material, there is no need to consider electrical conductivity to the lid member 20, the container body 10, and the electrode body 30, so the shim member 4 can be designed with fewer restrictions, thereby improving design freedom.

[0110] When the shim member 4 is made of a conductive material, the shim member 4 can be used as a conductor, so that, for example, at least one of the positive electrode 40 and the negative electrode 50 can be electrically connected to the container body 10 or the current collector plate 61 through the shim member 4. This makes it easy to reduce the electrical resistance and improve battery performance, in addition to reducing the need for dedicated lead members. For example, in this embodiment, the second shim member 80 may be formed of a conductive material, and the positive electrode terminal tab 44 may be electrically connected to the second shim member 80. This allows the positive electrode 40 and the container body 10 to be electrically connected via the second shim member 80, and allows the container body 10 to function as an external connection terminal for the positive electrode.

[0111] (Secondary battery manufacturing method) Next, an example of a method for manufacturing the secondary battery 1 of the first embodiment will be briefly described below. In the first embodiment, the current collecting plate 61 and the lid member 20 are thermally welded together via the sealant film 60. However, the sealant film 60 may be, for example, a single synthetic resin layer, or may be formed by joining multiple synthetic resin layers. Furthermore, the sealant film 60 may be a sealing material made of an inorganic material such as ceramic or glass.

[0112] In the first and second manufacturing methods described below, as described above, a sealant film 60 is formed by thermally welding together a first sealant and a second sealant made of synthetic resin.

[0113] <First manufacturing method> First, a process is performed in which the first seal material is superimposed on the lower surface of the current collector plate 61 and the two are combined together by thermal welding. This results in a current collector plate assembly in which the current collector plate 61 and the first seal material are combined together. Simultaneously with, or before or after, this step is performed to overlap the second sealant on the top surface of the lid member 20 and combine them into one by thermal welding, thereby obtaining a lid member assembly in which the lid member 20 and the second sealant are combined into one.

[0114] When the above-mentioned two steps are performed, the heat welding method may be heating by a heater, heating by irradiation with a laser beam, induction heating using high frequency waves, etc. By using these methods, heating can be performed locally and selectively in a shorter time than when each component is heated using a heater, and heat welding can be performed efficiently while suppressing the influence of heat on the first and second resin sealants.

[0115] In the case of laser beam irradiation, for example, after placing the first sealant on the current collector plate 61, a laser irradiator such as a fiber laser or YAG laser is used to irradiate the first sealant from above. At this time, the laser beam passes through the first sealant and is absorbed by the current collector plate 61, causing local heating of the current collector plate 61. As a result, the heat generated in the current collector plate 61 locally melts the first sealant, causing it to adhere closely to the current collector plate 61. In this way, the first sealant can be joined to the underside of the current collector plate 61 in a state where it is overlapped with good adhesion.

[0116] The laser beam has an irradiation diameter of about several tens of micrometers and can be irradiated continuously or linearly as pulses. By irradiating the laser beam circumferentially in the annular area where the current collector plate 61 and the first sealant overlap, the current collector plate 61 and the first sealant can be thermally welded in a ring shape. By forming multiple such circumferential welded areas concentrically, sufficient welding strength can be obtained even with a small welding area. This reduces the thermal effects on the first sealant.

[0117] Furthermore, when induction heating is performed, for example, the first sealant is placed on the current collector plate 61, and then the electromagnetic waves to be used are irradiated from above. At this time, similar to irradiation with a laser beam, the current collector plate 61 is selectively heated and generates heat, and further, only the surface portion of the first sealant that contacts the current collector plate 61 locally melts and adheres to the current collector plate 61. Depending on the conditions of induction heating, not only may the current collector plate 61 generate heat, but the first sealant may also be dielectrically heated by the irradiation with electromagnetic waves and melt, thereby adhering to the current collector plate 61. In this way, the first sealant can be joined to the underside of the current collector plate 61 in a state where it is overlapped with good adhesion.

[0118] For induction heating, electromagnetic waves in the frequency bands of, for example, very low frequency (VLF) to centimeter frequency (SHF) can be used. Specifically, so-called microwaves in the frequency band of, for example, 300 MHz to 30 GHz can be used. In particular, by using an oscillator with a magnetron in the 2.45 GHz frequency band, the irradiation device can be constructed inexpensively. Furthermore, it is also suitable to use a coil-type device to irradiate electromagnetic waves in the frequency band of 10 to 500 kHz, particularly in the frequency band of 20 to 100 kHz used in electromagnetic induction heating cookers.

[0119] Similar to the heat welding between the current collector plate 61 and the first sealant, the lid member 20 and the second sealant can also be heat welded by the above-mentioned method. Note that the adhesion between the current collecting plate 61 and the first sealant, and the adhesion between the lid member 20 and the second sealant can be further improved by previously performing a surface treatment on the metal surfaces of the current collecting plate 61 and the lid member 20 and the resin surfaces of the first sealant and the second sealant. Specifically, for example, an oxide film on the metal surface can be removed using electron beam irradiation or the like to create a clean surface. Furthermore, the resin surface can be modified and its properties adjusted using techniques such as electron beam irradiation or ozone oxidation. Furthermore, adhesion can be further improved by applying a primer to the surface-treated metal surface or resin surface beforehand and then carrying out the above-mentioned two-step heat welding.

[0120] After the above two steps are completed, the current collecting plate assembly and the lid member assembly are combined so that the first sealant and the second sealant overlap, and then a step of thermally welding the first sealant and the second sealant together is performed. This allows the current collecting plate 61 and the lid member 20 to be combined together via the sealant film 60, which is the first sealant and the second sealant integrated by thermal welding.

[0121] Simultaneously with, or before or after, the process of forming the electrode body 30 is carried out, and a process of combining the second shim member 80 onto the bottom wall portion 11 of the container body 10 is carried out. At this time, the second shim member 80 may be set so as to be overlapped on the bottom wall portion 11 of the container body 10, or may be set so as to be fixed integrally onto the bottom wall portion 11. Next, after pouring the electrolyte into the container body 10, the electrode body 30 is placed inside the container body 10 filled with the electrolyte, and a step is performed in which the first shim member 70 is set so as to overlap the electrode body 30.

[0122] Next, a step of assembling the lid member 20 so that it overlaps with the container body 10 is performed. This allows the lid member 20 to be arranged so that it overlaps with the bottom wall portion 11 in the direction of the battery axis O, via the electrode body 30, the first shim member 70, and the second shim member 80. Therefore, the lid member 20 can be supported using the electrode body 30, the first shim member 70, and the second shim member 80.

[0123] Finally, a process is performed in which the peripheral wall portion 12 of the container body 10 and the outer peripheral edge portion of the lid member 20 are welded together along the entire periphery. As described above, this process can employ resistance welding such as laser welding, ultrasonic welding, or seam welding, or friction stir welding. This allows the container body 10 and the lid member 20 to be welded together, resulting in an exterior body 2 in which the housing space 5 housing the electrode body 30, the first shim member 70, and the second shim member 80 is sealed. As a result, the secondary battery 1 shown in FIGS. 1 and 2 can be manufactured.

[0124] In particular, when performing the above-mentioned welding work, laser welding can be performed while applying pressure from above. Therefore, the container body 10 and the lid member 20 can be firmly and easily welded together, and the storage space 5 can be sealed with high airtightness. Furthermore, since the lid member 20 can be formed into a flat plate shape, processing of the lid member 20 is easy, and costs can be reduced. However, the welding work is not limited to laser welding.

[0125] During welding, the outer peripheral edge of the lid member 20 can be irradiated from above with a laser beam or the like, thereby locally heating and melting the outer peripheral edge of the lid member 20 and the upper opening edge of the peripheral wall 12 of the container body 10. Then, by solidifying the molten pool formed by the two melting together, a molten metal part (not shown) can be formed, and the outer peripheral edge of the lid member 20 and the peripheral wall 12 of the container body 10 can be welded together around the entire circumference.

[0126] In particular, by increasing the irradiation intensity by narrowing the beam diameter of the laser beam or the like, it is possible to form a deep molten pool, thereby increasing the welding strength. Therefore, from the viewpoint of performing strong welding, it is preferable to make the plate thickness of the lid member 20 thick. When irradiating a laser beam or the like, it is sufficient that the laser beam is irradiated from above onto the outer peripheral edge of the lid member 20. For example, the laser beam may be irradiated directly downward from above the outer peripheral edge of the lid member 20, or the laser beam may be irradiated diagonally downward from above the lid member 20 and on the battery axis O side, or the laser beam may be irradiated diagonally downward from above the lid member 20 and outside the container body 10.

[0127] <Second manufacturing method> Next, a second manufacturing method for manufacturing the secondary battery 1 using a different process order from the first manufacturing method will be described. In this manufacturing method, the electrolyte is finally injected using the through-hole 21 formed in the lid member 20. However, a step of previously forming a through-hole for injecting the electrolyte in the lid member 20, separate from the through-hole 21, may be performed.

[0128] In this manufacturing method, similar to the first manufacturing method, a process is carried out to form a current collector plate assembly in which a current collector plate 61 and a first seal material are combined together, and a lid member assembly in which a lid member 20 and a second seal material are combined together.

[0129] Simultaneously with, or before or after, the step of forming the electrode body 30 is carried out, and a step of combining the second shim member 80 onto the bottom wall portion 11 of the container body 10 is carried out. Next, the electrode body 30 is housed inside the container body 10, and a step of setting the first shim member 70 so as to overlap the electrode body 30 is carried out. At this stage, the electrolyte has not yet been poured.

[0130] Next, a process is performed in which the lid member assembly is assembled so as to overlap the container body 10. This allows the lid member assembly to be positioned so as to overlap the bottom wall portion 11 in the direction of the battery axis O, via the electrode body 30, the first shim member 70, and the second shim member 80. Therefore, the lid member assembly can be supported using the electrode body 30, the first shim member 70, and the second shim member 80. Next, a process is performed in which the peripheral wall portion 12 of the container body 10 and the outer peripheral edge portion of the lid member assembly are welded together around the entire periphery.

[0131] After the above welding operation, a step of injecting the electrolyte into the container body 10 is performed through the through-hole 21 formed in the lid member 20. At this time, it is also possible to inject the electrolyte in a vacuum, for example. Finally, the current collecting plate assembly is combined with the lid member assembly so that the first sealant and the second sealant overlap, and then a process of thermally welding the first sealant and the second sealant together is performed. This allows the current collecting plate 61 and the lid member 20 to be combined together as a single unit via the sealant film 60, which is the first sealant and the second sealant integrated by thermal welding, and also allows the through-hole 21 to be closed.

[0132] As a result, the secondary battery 1 shown in FIGS. 1 and 2 can be manufactured. In particular, according to the present manufacturing method, the electrolyte is injected after welding the container body 10 and the lid member 20, so the electrolyte is not affected by the welding process. This makes it easier to perform the welding work and also makes it easier to maintain the quality and characteristics of the electrolyte.

[0133] Although the first and second manufacturing methods have been described above as examples of methods for manufacturing the secondary battery 1, the method is not limited to these methods. As described above, in the first and second manufacturing methods, the sealant film 60 is formed by thermally welding the first and second sealing materials together, but a single (single-layer) sealant film 60 may also be used. In this case, it is not necessary to fabricate a current collector assembly and a lid member assembly separately, and it is sufficient to combine the current collector plate 61 and the lid member 20 integrally via one sealant film 60.

[0134] (Modification of the first embodiment) In the first embodiment, an example was described in which both the first shim member 70 and the second shim member 80 were provided, but the present invention is not limited to this, and it is also possible to use only either the first shim member 70 or the second shim member 80. The number of shim members 4 to be used can be determined depending on the gap between the electrode body 30 and the lid member 20, the gap between the electrode body 30 and the bottom wall portion 11, etc.

[0135] Furthermore, in the above embodiment, the first shim member 70 is formed in a flat dish shape, and the second shim member 80 is formed in a flat plate shape, but the present invention is not limited to this case. For example, the first shim member 70 formed in the shape of a flat ring plate may be used, or the second shim member 80 formed in the shape of a flat dish may be used.

[0136] 6, the first shim member 70 formed in a flat dish shape may be turned upside down and set so that the shim plate 71 contacts the underside of the lid member 20. Even in this case, the same effects as those of the first embodiment can be achieved. In addition, in this case, the first shim member 70 can be arranged so that the bent portion 72 extends downward from the shim plate 71, and therefore an annular space portion (insulated space) 81 surrounded by the upper end portion of the peripheral wall portion 12 of the container body 10, the lid member 20, and the bent portion 72 can be formed within the storage space 5. This makes it possible to effectively prevent inconveniences such as contamination of the electrode body 30 due to components derived from the molten metal (for example, vapors such as welding fumes, plasma plumes, debris, etc.) when the container body 10 and the lid member 20 are welded together.

[0137] (Second embodiment) Next, a second embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[0138] As shown in FIG. 7, in a secondary battery (electrochemical cell according to the present invention) 90 of this embodiment, a first shim member 91 is a disc spring that is elastically deformable in the direction of the battery axis O. As shown in Figures 7 and 8, the first shim member 91 has a through hole 92 formed in the center and is formed in a conical shape (tapered cross section) that extends downward from the inner peripheral edge 93 to the outer peripheral edge 94.

[0139] The first shim member 91 is disposed coaxially with the battery axis O between the electrode body 30 and the lid member 20. In the illustrated example, the first shim member 91 has an inner diameter sized to surround the protective portion 60a of the sealant film 60 from the radially outer side, and an outer diameter sized to fit inside the peripheral wall portion 12.

[0140] (Action of secondary batteries) The secondary battery 90 of this embodiment configured as described above can also achieve the same effects as those of the first embodiment. In addition, when the lid member 20 is combined with the container body 10, the first shim member 91 can be elastically deformed in the direction of the battery axis O. Therefore, the first shim member 91 can be used to appropriately fill the gap formed between the lid member 20 and the electrode body 30 without having to adjust the thickness of the first shim member 91 in advance to correspond to the gap. Therefore, the lid member 20 can be supported more stably using the electrode body 30, the first shim member 91 and the second shim member 80, and welding work can be performed while further suppressing positional deviation of the lid member 20 relative to the container body 10.

[0141] (Modification of the second embodiment) In the second embodiment, as shown in FIG. 9, the first shim member 91 may be positioned using the inside of the through hole 21 formed in the lid member 20 so that the first shim member 91 is sandwiched between the current collector plate 61 and the electrode body 30. In this case, the first shim member 91 is formed so that its inner diameter is smaller than the diameter of the through hole 21 formed in the lid member 20 and its outer diameter is larger than the diameter of the through hole 21. This allows the first shim member 91 to be arranged so as to be sandwiched between the current collecting plate 61 and the electrode body 30.

[0142] The first shim member 91 is prevented from coming into contact with the lid member 20 by the protective portion 60a of the sealant film 60. Therefore, even if the first shim member 91 is made of a conductive material, it is possible to prevent electrical conduction between the current collecting plate 61 and the lid member 20 through the first shim member 91.

[0143] Even with a secondary battery 90 configured in this manner, the current collector plate 61 is integrally combined with the lid member 20, so the lid member 20 can be supported using the electrode body 30, the first shim member 91, and the second shim member 80, and the same effects as those of the second embodiment can be achieved. In the second embodiment, for example, a plurality of first shim members 91 in the shape of a disc spring may be used in combination, with the first shim members 91 being inverted upside down in the direction of the battery axis O.

[0144] (Third embodiment) Next, a third embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this third embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[0145] As shown in FIGS. 10 and 11, a secondary battery (electrochemical cell according to the present invention) 100 of this embodiment differs from the first embodiment in the shape of the lid member. The lid member 110 of this embodiment (sealing plate according to the present invention) is formed in a circular shape when viewed from above, and is formed in a cylindrical shape with a top, including a top wall portion 111 arranged to face the bottom wall portion 11 of the container body 10 in the direction of the battery axis O, with the electrode body 30 sandwiched between them, and an inner peripheral wall portion 112 connected around the entire circumference of the outer peripheral edge portion 94 of the top wall portion 111 and extending upward from the top wall portion 111.

[0146] The lid member 110 is disposed inside the peripheral wall 12 so that the top wall 111 is positioned lower than the upper opening edge of the peripheral wall 12 of the container body 10, and so that the upper opening edge of the peripheral wall 12 and the upper opening edge of the inner peripheral wall 112 are flush with each other. As a result, the inner peripheral wall 112 is welded to the inside of the peripheral wall 12 of the container body 10 in a radially double-overlapping state. A through-hole 21 is formed in the center of the top wall 111.

[0147] (Action of secondary batteries) The secondary battery 100 of this embodiment configured as described above can achieve the same effects as those of the first embodiment. In addition, during assembly, before welding, the lid member 110 can be fitted, for example, by an interference fit, inside the peripheral wall 12 of the container body 10. Therefore, by welding the container body 10 and the lid member 110 together, the storage space 5 can be sealed with even higher airtightness.

[0148] When fitting the lid member 110 inside the peripheral wall 12 of the container 10, minute holes that allow gas inside the container 10 to escape to the outside may be formed in the lid member 110 in advance. In this case, as the lid member 110 is fitted inside the peripheral wall 12 of the container 10, the pressure inside the container 10 can be released through the minute holes, preventing the internal pressure of the container 10 from increasing unintentionally. The minute holes may be finally sealed.

[0149] Furthermore, since the upper opening edge of the peripheral wall portion 12 and the upper opening edge of the inner peripheral wall portion 112 both face upward, during welding, it is possible to perform laser welding, for example, while approaching from above. Therefore, the peripheral wall portion 12 and the inner peripheral wall portion 112 can be firmly and easily welded together by, for example, butt welding, and the inside of the accommodation space 5 can be sealed with high airtightness.

[0150] In this embodiment, welding can be performed by irradiating the boundary between the peripheral wall portion 12 and the inner peripheral wall portion 112 with a laser beam or the like from above, and by increasing the irradiation intensity by narrowing the beam diameter, a deep molten pool can be formed. This increases the welding strength and enables reliable welding.

[0151] (Modification of the third embodiment) In the third embodiment, as shown in Fig. 12, the peripheral wall 12 of the container body 10 may be formed so as to extend radially outward as it extends upward. In other words, the container body 10 may be formed so that the peripheral wall 12 gradually widens in diameter as it extends upward.

[0152] Specifically, as shown in FIG. 13, the peripheral wall portion 12 includes a first peripheral wall portion 12a extending radially outward as it moves upward from the outer peripheral edge portion 94 of the bottom wall portion 11, and a second peripheral wall portion 12b extending radially outward as it moves upward from the upper end portion of the first peripheral wall portion 12a.

[0153] The first peripheral wall portion 12a is inclined at a first inclination angle θ1 with respect to a normal line N perpendicular to the bottom wall portion 11, and is formed so as to increase in diameter as it extends upward. The second peripheral wall portion 12b is inclined at a second inclination angle θ2 with respect to the normal line N that is larger than the first inclination angle θ1, and is formed so as to increase in diameter as it extends upward more than the first peripheral wall portion 12a. In this way, the container body 10 is formed into an inverted tapered cylindrical shape whose diameter increases in two stages upward by the first peripheral wall portion 12a and the second peripheral wall portion 12b.

[0154] 12, the lid member 110 has an inner peripheral wall portion 112 that extends radially outward as it extends upward from the outer peripheral edge 94 of the top wall portion 111 in accordance with the shape of the second peripheral wall portion 12b, and is inclined at a second inclination angle θ2 with respect to the normal line N. As a result, the inner peripheral wall portion 112 is in contact with the second peripheral wall portion 12b without any gaps around the entire circumference. Therefore, the lid member 110 is welded to the inside of the second peripheral wall portion 12b in a state where the inner peripheral wall portion 112 overlaps twice in the radial direction.

[0155] The secondary battery 100 configured as described above can also achieve the same effects as those of the third embodiment. In addition, because the second peripheral wall portion 12b is inclined, when the lid member 110 is assembled to the container body 10, the lid member 110 can be assembled with the inner peripheral wall portion 112 overlapping the second peripheral wall portion 12b from above. This allows the lid member 110 to be supported by the second peripheral wall portion 12b in addition to the support provided by the electrode body 30, the first shim member 70, and the second shim member 80. Therefore, welding can be performed while effectively suppressing misalignment of the lid member 110 with respect to the container body 10, and the container body 10 and the lid member 110 can be welded and joined more accurately and appropriately.

[0156] In addition, when performing welding work, in order to properly irradiate a laser beam or the like onto the second peripheral wall portion 12b and the inner peripheral wall portion 112, the laser beam or the like may be irradiated, for example, diagonally downward from above the lid member 110 toward the inner peripheral wall portion 112, or horizontally or diagonally upward from the outside of the container body 10 toward the second peripheral wall portion 12b.

[0157] Furthermore, since the first peripheral wall portion 12a of the container body 10 is inclined at the first inclination angle θ1, even when the container body 10 is formed by press working using a molding die or the like, the container body 10 can be easily released from the molding die, which can lead to improved manufacturing efficiency of the secondary battery 100.

[0158] (Fourth embodiment) Next, a fourth embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this fourth embodiment, the same components as those in the third embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[0159] As shown in Figure 14, in the secondary battery (electrochemical cell according to the present invention) 120 of this embodiment, the lid member (sealing plate according to the present invention) 130 includes a top wall portion 111, an inner peripheral wall portion 112 extending upward from the outer peripheral edge portion of the top wall portion 111, and an annular flange portion 131 extending radially outward from the upper end portion of the inner peripheral wall portion 112. The inner peripheral wall portion 112 protrudes slightly upward beyond the peripheral wall portion 12 of the container body 10. The flange portion 131 extends radially outward from the upper end portion of the inner peripheral wall portion 112 and is welded to the upper open end of the peripheral wall portion 12 in a state where it overlaps from above around the entire circumference.

[0160] (Action of secondary batteries) The secondary battery 120 of this embodiment configured as described above can achieve the same effects as those of the fourth embodiment. In addition, during assembly, the lid member 130 can be placed over the upper opening edge of the peripheral wall 12 of the container body 10 from above, and then welding can be performed while applying pressure to the lid member 130 from above. This makes it easy to firmly weld the container body 10 and the lid member 130 together, and enables the storage space 5 to be sealed with even higher airtightness.

[0161] (Fifth embodiment) Next, a fifth embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this fifth embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. In the first embodiment, the current collecting plate 61 is disposed on the upper surface side of the lid member 20, but in this embodiment, the current collecting plate 61 is disposed on the lower surface side of the lid member 20.

[0162] 15, in a secondary battery (electrochemical cell according to the present invention) 140 of this embodiment, a current collector 61 is welded to the lower surface of a lid member 20 via a sealant film 60. As a result, the current collector 61 is integrally combined with the lid member 20 so as to cover a through-hole 21 formed in the lid member 20 from below. Therefore, the current collector 61 is partially exposed upward through the through-hole 21.

[0163] Furthermore, the shim member 4 of this embodiment includes a first shim member 141 arranged between the current collector plate 61 and the electrode body 30. Even in this case, the first shim member 141 is arranged in a state where it is sandwiched between the lid member 20 and the electrode body 30 in the direction of the battery axis O, with the current collector plate 61 sandwiched therebetween, and is arranged so as to fill the gap between the lid member 20 and the electrode body 30.

[0164] Furthermore, since the first shim member 141 of this embodiment is disposed below the current collector plate 61, it is possible to easily connect, for example, a negative electrode terminal tab to the current collector plate 61. Therefore, it is not necessary to form a through hole in the first shim member 141. In the illustrated example, the first shim member 141 is formed in a flat disk shape, similar to the second shim member 80. However, this is not limited to this case, and the first shim member 141 may also be formed in a flat dish shape without a through hole. Furthermore, the first shim member 141 may be formed of a conductive material, and the current collector plate 61 and the first shim member 141 may be electrically connected to each other. In this case, by electrically connecting the negative electrode terminal tab to the first shim member 141, the current collector plate 61 can function as an external connection terminal for the negative electrode.

[0165] In this embodiment, electroless plating may be performed by introducing a plating solution inside the protective portion 60a of the sealant film 60. In this case, a metal plating film (not shown) can be formed on the portion of the current collector plate 61 that is exposed to the outside, thereby improving the electrical connectivity with the external connection terminal, durability, etc.

[0166] (Action of secondary batteries) The secondary battery 140 of this embodiment configured as described above can also achieve the same effects as those of the first embodiment. Even if the current collector 61 is disposed on the underside of the lid member 20, the current collector 61 can be partially exposed through the through-hole 21, and can therefore function as an external connection terminal for the negative electrode. Therefore, the terminal portion of an external terminal (not shown) can be brought into contact with the current collector 61 in a non-contact state with the lid member 20, thereby electrically connecting the external terminal and the current collector 61, and the secondary battery 140 can be used.

[0167] The configuration in which the current collecting plate 61 is disposed on the underside of the lid member 20 may be applied to the first to fourth embodiments described above, and may also be applied to other embodiments described below.

[0168] (Sixth embodiment) Next, a sixth embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this sixth embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[0169] As shown in FIG. 16, a secondary battery (electrochemical cell according to the present invention) 150 of this embodiment differs from that of the first embodiment in the shape of a lid member (sealing plate according to the present invention) 160. The lid member 160 of this embodiment is formed in a circular shape when viewed from above, and is formed in a topped cylindrical shape having a top wall portion 161 arranged to face the bottom wall portion 11 of the container body 10 in the direction of the battery axis O, with the electrode body 30 sandwiched between them, and an inner peripheral wall portion 162 connected around the entire outer periphery of the top wall portion 161 and extending downward from the top wall portion 161.

[0170] The lid member 160 is disposed so that the top wall portion 161 is located above the upper opening edge of the peripheral wall portion 12 of the container body 10, and the inner peripheral wall portion 162 fits snugly inside the peripheral wall portion 12 of the container body 10. As a result, the entire inner peripheral wall portion 162 is welded to the inside of the peripheral wall portion 12 of the container body 10 in a radially double-overlapping state.

[0171] (Action of secondary batteries) The secondary battery 150 of this embodiment can also achieve the same effects as those of the first embodiment. In addition, because the peripheral wall 12 of the container body 10 and the inner peripheral wall 162 of the lid member 160 overlap each other over a wide area, the peripheral wall 12 and the inner peripheral wall 162 can be easily welded together, and can be welded in multiple stages at intervals in the direction of the battery axis O, for example. This further improves the airtightness of the storage space 5.

[0172] In this embodiment, welding can be performed by irradiating a laser beam or the like horizontally from the outside of the container body 10 toward the peripheral wall portion 12, but in order to form a deep molten pool and increase the strength of the welding joint, it is preferable to make the thickness of the peripheral wall portion 12, which is the incident side of the laser beam, thicker than the thickness of the inner peripheral wall portion 162.

[0173] (Seventh embodiment) Next, a seventh embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this seventh embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. In the first embodiment (the same applies to the second to sixth embodiments), a configuration has been described in which the current collecting plate 61 is welded to the lid member 20 via the sealant film 60. In contrast, in the present embodiment, the current collecting plate 61 is welded to the bottom wall portion 11 of the container body 10 via the sealant film 60.

[0174] 17, in a secondary battery (electrochemical cell according to the present invention) 170 of this embodiment, a through-hole 171 that passes through the bottom wall 11 in the vertical direction is formed in the center of the bottom wall 11 of the container body 10, coaxial with the battery axis O. The shape of the through-hole 171 is not particularly limited, but is formed, for example, in a circular shape when viewed from above.

[0175] A current collecting plate 61 is heat-welded to the bottom wall portion 11 in which the through-hole 171 is formed via a sealant film 60. Specifically, the current collecting plate 61 is heat-welded to the lower surface of the bottom wall portion 11 via the sealant film 60, and is exposed downward over its entire surface. The sealant film 60 is formed in a ring shape surrounding the through-hole 171 formed in the bottom wall portion 11, and is arranged so as to overlap the lower surface of the bottom wall portion 11 while being coaxial with the battery axis O. In the illustrated example, the sealant film 60 is folded upward from the inner peripheral edge portion, and has a protective portion 60a that protects the inner peripheral surface of the through-hole 171 formed in the bottom wall portion 11 over the entire circumference.

[0176] The current collecting plate 61 is formed in a circular shape in a plan view with a diameter smaller than the outer diameter of the sealant film 60, and is arranged coaxially with the battery axis O and overlapping the lower surface of the sealant film 60. In this way, the current collecting plate 61 closes the through-hole 171 from below.

[0177] In the lid member 20 of this embodiment, the current collector plate 61 is combined with the container body 10 side, so the through-hole 21 in the first embodiment is not necessary. Furthermore, the shim member 4 of this embodiment includes a first shim member 180 arranged between the lid member 20 and the electrode body 30, and a second shim member 190 arranged between the bottom wall portion 11 and the electrode body 30.

[0178] The first shim member 180 is formed, for example, in the shape of a flat disk, and is arranged sandwiched between the lid member 20 and the electrode body 30 in the direction of the battery axis O so as to fill the gap between the lid member 20 and the electrode body 30.

[0179] The second shim member 190 is formed in a flat dish shape and includes a shim plate 191 that is circular in plan view and is arranged so as to overlap the electrode body 30 from below, and a bent portion 192 that is connected around the entire outer edge of the shim plate 191 and is bent downward while curving.

[0180] A through-hole 193 is formed in the center of the shim plate 191, penetrating the shim plate 191 from top to bottom. The through-hole 193 is formed in a circular shape in a plan view, and is disposed coaxially with the battery axis O. As a result, the shim plate 191 is formed in a ring shape. The lower edge of the bent portion 192 contacts the bottom wall portion 11 from above. As a result, the second shim member 190 is disposed in a state where it is sandwiched between the bottom wall portion 11 and the electrode body 30 in the direction of the battery axis O so as to fill the gap between the bottom wall portion 11 and the electrode body 30.

[0181] In this embodiment, for example, the lid member 20 functions as an external connection terminal for the negative electrode, and the current collecting plate 61 functions as an external connection terminal for the positive electrode. When the negative electrode 50 is electrically connected to the lid member 20, for example, the negative electrode terminal tab 54 may be electrically connected directly to the lid member 20, or the negative electrode terminal tab 54 and the lid member 20 may be electrically connected via a conductor equivalent to a lead wire (not shown). Furthermore, the negative electrode terminal tab 54 and the lid member 20 may be electrically connected via a first shim member 180. When conducting the positive electrode 40 to the current collector 61, for example, the positive terminal tab 44 may be electrically connected directly to the current collector 61 through the through hole 171 of the container body 10 and the through hole 193 of the second shim member 190, or the positive terminal tab 44 may be electrically connected to the current collector 61 by placing a conductor corresponding to a lead wire (not shown) connecting the positive terminal tab 44 to the current collector 61 inside the through holes 171, 193.

[0182] (Action of secondary batteries) Even with the secondary battery 170 of this embodiment configured in this manner, the lid member 20 can be supported from below using the electrode body 30, the first shim member 180, and the second shim member 190, so that the same effects as those of the first embodiment can be achieved.

[0183] (Eighth embodiment) Next, an eighth embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this eighth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted. In the first embodiment (as well as the second to seventh embodiments), the electrode body 30 has been described as an example of a laminated electrode in which positive electrodes 40 and negative electrodes 50 are wound flat so as to be alternately stacked in the direction of the battery axis O with a separator (not shown) sandwiched therebetween. In this embodiment, the battery includes an electrode body configured by being wound multiple times in the radial direction around the central axis of a support column that is arranged coaxially with the battery axis O.

[0184] As shown in FIG. 18, a secondary battery (electrochemical cell according to the present invention) 200 of this embodiment includes a support part 201 housed in the housing space 5 of the exterior body 2. The support pillar 201 is formed in a shaft shape extending in the vertical direction along the battery axis O, and is arranged coaxially with the battery axis O. In the illustrated example, the support pillar 201 is formed in a hollow cylindrical shape, and its outer diameter is smaller than the diameter of the through-hole 21. As a result, the support pillar 201 is arranged so that its upper end contacts the current collector plate 61 from below through the through-hole 21, and its lower end contacts the second shim member 80 arranged on the bottom wall 11 of the container body 10 from above. Therefore, the support pillars 201 play a role in supporting the lid member 20 from below via the current collector plate 61 .

[0185] The support 201 is made of an insulating material such as an inorganic material, such as ceramic, or a synthetic resin material. When the support 201 is made of synthetic resin, for example, a thermoplastic resin having a melting point equivalent to that of the separator 211 can be suitably used. Specifically, synthetic resin materials such as PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), and LCP (liquid crystal polymer) can be used. Furthermore, copolymers and blend polymers of these synthetic resins can also be used.

[0186] (electrode body) As shown in FIG. 18, the electrode body 210 of this embodiment has a positive electrode 212 and a negative electrode 213 arranged with a separator 211 sandwiched between them, and is a wound electrode that is wound multiple times around a battery axis O. Specifically, the electrode body 210 is wound around the support part 201, with the positive electrode 212 and the negative electrode 213 overlapping each other with the separator 211 sandwiched between them, and is wound multiple times radially around the central axis C of the support part 201, which is arranged coaxially with the battery axis O. Therefore, the support part 201 of this embodiment also functions as a winding core when winding the electrode body 210.

[0187] The electrode body 210 is wound in a multiple spiral shape around the battery axis O (the central axis C of the support section 201) in a plan view seen from the direction of the battery axis O. In this embodiment, the electrode body 210 is wound so that the negative electrode 213, separator 211, positive electrode 212, separator 211, negative electrode 213, separator 211, and positive electrode 212 are repeatedly arranged in this order from the innermost layer located on the support section 201 side of the electrode body 210 to the outermost layer located on the peripheral wall section 12 side of the container body 10.

[0188] As shown in FIG. 19, in the unfolded state before winding the electrode body 210, the positive electrode 212 is formed in the shape of a single sheet including a long positive electrode current collector (positive electrode current collector foil) 212a formed so as to extend in a strip shape with a constant width, and a positive electrode active material layer 212b formed by coating or the like on one or both sides of the positive electrode current collector 212a.

[0189] A positive electrode terminal tab 212c is formed on one end of the positive electrode current collector 212a that is located away from the support portion 201. The positive electrode terminal tab 212c does not have the positive electrode active material layer 212b formed thereon, and is capable of being electrically connected to other components. The positive electrode terminal tab 212c is arranged on the outer layer side of the electrode body 210 when the electrode body 210 is wound. The positive electrode current collector 212a and the positive electrode active material layer 212b can be made of the same materials as those in the first embodiment.

[0190] The negative electrode 213 is formed in the shape of a single sheet including a long negative electrode current collector (negative electrode current collector foil) 213a formed so as to extend in a strip shape with a constant width in the unfolded state before winding the electrode body 210, and a negative electrode active material layer 213b formed by coating or the like on one or both sides of the negative electrode current collector 213a.

[0191] A negative electrode terminal tab 213c is formed on one end of the negative electrode current collector 213a that is located away from the support portion 201. The negative electrode terminal tab 213c does not have the negative electrode active material layer 213b formed thereon, and is capable of being electrically connected to other components. The negative electrode terminal tab 213c is arranged on the outer layer side of the electrode body 210 when the electrode body 210 is wound. The negative electrode current collector 213a and the negative electrode active material layer 213b can be made of the same materials as those in the first embodiment.

[0192] 18 is formed of, for example, a microporous film made of a resin such as polyolefin, a nonwoven fabric made of glass or resin, or a laminate of fibers such as cellulose fibers, and is capable of passing lithium ions through ion permeable pores (not shown). Further, separator 211 may be, for example, a porous body capable of retaining an electrolyte solution in the pores, or a resin layer having lithium ion conductivity.

[0193] The separator 211 is disposed between the entire layers of the positive electrode 212 and the negative electrode 213, and insulates the positive electrode 212 from the negative electrode 213. Therefore, the separator 211 is disposed so as to be interposed between the positive electrode 212 and the negative electrode 213 at least over the entire region where the positive electrode 212 and the negative electrode 213 face each other.

[0194] The electrode body 210 configured as described above is wound around the support part 201 as shown in FIG. 18, whereby it is combined integrally with the support part 201 and becomes a wound electrode in which the positive electrode 212 and the negative electrode 213 are wound around the central axis C of the support part 201 so as to be stacked in multiple layers in the radial direction with the separator 211 sandwiched between them. Even when the electrode body 210 is configured in this manner, for example, the current collector plate 61 can function as an external connection terminal for the negative electrode, and the container body 10 can function as an external connection terminal for the positive electrode.

[0195] (Formation of electrode body) A brief description will be given below of a case where the electrode body 210 is formed using the support part 201 as a winding core. 19 , after preparing the separator 211, the positive electrode 212, and the negative electrode 213, the separator 211 is welded to the outer peripheral surface of the support part 201. In this way, the welded part 202 formed by welding the outer peripheral surface of the support part 201 and the separator 211 to each other can be used as a positioning part, and the separator 211 can be positioned relative to the support part 201.

[0196] If the length of separator 211 is predetermined, a portion of separator 211 shifted from the center in the longitudinal direction toward region R1 where positive electrode 212 is overlapped is welded to the outer peripheral surface of support portion 201. This makes it possible to ensure that region R2 of separator 211 where negative electrode 213 is overlapped is larger than region R1 where positive electrode 212 is overlapped.

[0197] Next, as indicated by an arrow M in Fig. 19, the support part 201 is rotated around the central axis C. At this time, the support part 201 is rotated so that the region R2 of the separator 211, on which the negative electrode 213 is to be superimposed, is wound around the support part 201 first. Next, the separator 211 and the negative electrode 213 are overlapped so that the negative electrode 213 is inserted between the separator 211 that has been wound around the support part 201 in advance and the support part 201. At this time, the negative electrode 213 is inserted as indicated by arrow S in FIG. 20 until it abuts against the welded part 202. In this state, by further rotating the support part 201, the negative electrode 213 can be wound around the support part 201 in advance, and the negative electrode 213 can form the innermost layer of the electrode body 210.

[0198] Furthermore, the support part 201 is continuously rotated while overlapping the positive electrode 212 on the separator 211, to wind up the separator 211, the positive electrode 212, and the negative electrode 213. As a result, it is possible to produce an electrode body 210 wound up around the support part 201, as shown in FIG.

[0199] (Action of secondary batteries) The secondary battery 200 of this embodiment configured as described above can also achieve the same effects as those of the first embodiment. In addition to supporting the lid member 20 using the first shim member 70 and the second shim member 80, the lid member 20 can also be supported using the support portion 201, so unintended deformation such as bending of the lid member 20 can be more effectively suppressed, and welding work can be performed while further suppressing positional deviation of the lid member 20 relative to the container body 10.

[0200] Furthermore, after the electrode body 210 is formed by winding, the electrode body 210 together with the support portions 201 can be housed in the container body 10. This allows the assembly work to be carried out efficiently, leading to improved productivity.

[0201] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their modifications include, for example, those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are equivalent.

[0202] For example, in each of the above embodiments, a secondary battery has been described as an example of an electrochemical cell, but the present invention is not limited to this case and may be applied to various types of electricity storage devices, such as an electric double layer capacitor or a lithium ion capacitor.

[0203] When the electrochemical cell is applied to an electric double layer capacitor, the positive and negative electrodes may be used as a pair of polarizable electrodes. In this case, the polarizable electrodes may be, for example, activated carbon powder obtained by activation treatment, mixed with a conductive additive and a binder, and molded by calendar roll pressing or powder compacting press. The press molding may also be performed by a die punch press. The electrolyte can be, for example, one in which a supporting salt such as a quaternary ammonium salt is dissolved in a non-aqueous solvent. It is also possible to mix the material into a slurry, which can then be coated, dried, and processed into an electrode. It is also possible to use polytetrafluoroethylene (PTFE) as a binder, knead and mold the material into a plate shape, and then bond the plate to a current collecting foil with a conductive paste to form an electrode.

[0204] When the electrochemical cell is applied to a lithium-ion capacitor, the polarizable electrode described above can be used for only one of the positive and negative electrodes, and an electrode for a lithium-ion battery can be used for the other electrode. The same electrolyte as that used in a lithium-ion battery can be used. In particular, the use of lithium titanate (LTO) as an electrode for a lithium-ion battery can improve current characteristics.

[0205] Furthermore, in each of the above embodiments, examples of outer casings with different shapes have been described, but the shapes of the container body and the lid member may be changed as appropriate as long as the lid member can be welded to a container body formed in a bottomed cylindrical shape to close the opening of the container body. For example, the rigidity of the lid member may be improved by forming an annular groove with a U-shaped cross section in the lid member. Furthermore, the lid member may be formed in a cylindrical shape with a top, or the lid member 130 shown in FIG. 14 may be used upside down.

[0206] Furthermore, in each of the above embodiments, the electrode body is not limited to a specific structure, and any known electrode body may be used as appropriate. For example, as shown in FIG. 21, an electrode assembly (laminated electrode assembly) 220 may be formed by stacking positive electrodes 222 and negative electrodes 223 in multiple layers in the direction of the battery axis O with separators 221 sandwiched therebetween. In the illustrated example, the electrode body 220 is formed by laminating 12 layers of positive electrodes 222 and 12 layers of negative electrodes 223. However, the number of layers is not limited to 12 and may be changed as appropriate.

[0207] 21 to 23, the positive electrode 222 is formed in the shape of a single sheet including a thin-film positive electrode current collector (positive electrode current collector foil) 222a formed in a D-shape in plan view and positive electrode active material layers 222b formed by coating or the like on both sides of the positive electrode current collector 222a. A part of the positive electrode current collector 222a is a positive electrode terminal tab 222c where the positive electrode active material layer 222b is uncoated, and protrudes outward.

[0208] Separator 221 is a sheet formed in a D-shape in plan view corresponding to the shape of positive electrode 222, and is arranged to sandwich positive electrode 222 from above and below. In this case, separator 221 is formed to be one size larger than positive electrode 222. As a result, positive electrode 222 is sandwiched and protected from above and below by two separators 221. The positive electrode terminal tab 222c is disposed so as to protrude outward beyond the separator 221.

[0209] The negative electrode 223 is formed in the shape of a single sheet including a thin-film negative electrode current collector (negative electrode current collector foil) 223a formed in a D-shape in plan view corresponding to the shape of the positive electrode 222, and negative electrode active material layers 223b formed by coating or the like on both sides of the negative electrode current collector 223a. A part of the negative electrode current collector 223a is a negative electrode terminal tab 223c where the negative electrode active material layer 223b is uncoated, and protrudes outward.

[0210] The negative electrode 223 is formed to have a size equal to or slightly smaller than the separator 221. Therefore, the positive electrode 222 is formed to have a size smaller than the negative electrode 223. The positive electrode terminal tab 222c is arranged to protrude outward beyond the separator 221 and is arranged not to face the positive electrode terminal tab 222c in the up-down direction.

[0211] 21, the electrode assembly 220 is configured by alternately stacking 12 layers of positive electrodes 222 and negative electrodes 223 with separators 221 sandwiched therebetween. Furthermore, the multiple (12) positive electrode terminal tabs 222c and negative electrode terminal tabs 223c are arranged side by side along the direction of the battery axis O.

[0212] The multiple positive electrode terminal tabs 222c are electrically connected to one another by being gathered together by, for example, welding, etc. Similarly, the multiple negative electrode terminal tabs 223c are electrically connected to one another by being gathered together by, for example, welding, etc.

[0213] The electrode body 220 is placed in the accommodation space 5, with the positive electrode terminal tab 222c, for example, being electrically connected to the container body 10, and the negative electrode terminal tab 223c being electrically connected to the current collector plate 61. This allows the current collector plate 61 to function as an external connection terminal for the negative electrode, and the container body 10 to function as an external connection terminal for the positive electrode, allowing the secondary battery to be used.

[0214] Furthermore, as another electrode body, for example, as shown in FIG. 24, an electrode body 230 may be employed in which a positive electrode 232 and a negative electrode 233 formed in the shape of a thin disk are stacked in the direction of the battery axis O.

[0215] The positive electrode 232 is formed in the shape of a single sheet including a thin-film positive electrode current collector (positive electrode current collector foil) 232a formed in a ring shape in a plan view, and positive electrode active material layers 232b formed by coating or the like on both sides of the positive electrode current collector 232a. In the illustrated example, the positive electrode active material layers 232b are hatched in dots to make the drawing easier to see. The positive electrode active material layer 232b is formed on the positive electrode current collector 232a except for the inner peripheral edge portion, thereby enabling current collection to be performed using the inner peripheral edge portion 232c of the positive electrode current collector 232a.

[0216] The negative electrode 233 is formed in the shape of a single sheet including a thin-film negative electrode current collector (negative electrode current collector foil) 233a formed in a ring shape in a plan view corresponding to the shape of the positive electrode 232, and negative electrode active material layers 233b formed by coating or the like on both sides of the negative electrode current collector 233a. In the illustrated example, the negative electrode active material layer 233b is hatched in dots to make the drawing easier to see.

[0217] The negative electrode 233 is formed so that its outer diameter is larger than that of the positive electrode 232 and its inner diameter is larger than that of the negative electrode 233. This allows the entire area of ​​the positive electrode active material layer 232b to face the negative electrode active material layer 233b in the direction of the battery axis O. The negative electrode active material layer 233b is formed on the negative electrode current collector 233a except for the outer peripheral edge portion, thereby enabling current collection to be performed using the outer peripheral edge portion 233c of the negative electrode current collector 233a.

[0218] When using an electrode body 230 having the positive electrode 232 and the negative electrode 233 configured as described above, the positive electrode 232 and the negative electrode 233 may be alternately stacked in multiple layers (e.g., 12 layers) as in the electrode body 220 shown in FIG. 21 .

[0219] In this case, the electrode body 230 is placed in the accommodation space 5, and is electrically connected to the container body 10, for example, by using the inner peripheral edge 232c of the positive electrode current collector 232a, and the outer peripheral edge 233c of the negative electrode current collector 233a is electrically connected to the current collector plate 61. This allows the current collector plate 61 to function as an external connection terminal for the negative electrode, and the container body 10 to function as an external connection terminal for the positive electrode, allowing the secondary battery to be used.

[0220] When forming the positive electrode 232, for example, the positive electrode active material layer 232b is formed on both sides of the positive electrode current collector 232a formed in the shape of a long sheet by coating or the like. Next, the sheet-like positive electrode current collector 232a is processed into a ring shape by punching or the like, and the positive electrode active material layer 232b is further trimmed and partially removed by laser processing or the like, thereby forming the positive electrode 232. The negative electrode 233 can also be formed in a similar manner.

[0221] 24 does not necessarily have to be formed in a ring shape, but may be formed in a disk shape. In this case, current collection can be performed by utilizing the central portion of the positive electrode current collector 232a. 24, when the positive electrode 232 is formed in a ring shape, the positive electrode active material layer 232b may be applied to the entire area of ​​the positive electrode current collector 232a, including the inner peripheral edge 232c of the positive electrode current collector 232a. Even in this case, for example, by combining a current collector rod so as to pierce the positive electrode 232, current can be collected from the positive electrode current collector 232a covered with the positive electrode active material layer 232b.

[0222] Furthermore, in the negative electrode 233 shown in FIG. 24, the negative electrode current collector 233a may be formed so as to have a negative electrode terminal tab, and the negative electrode active material layer 233b may be coated over the entire area of ​​the negative electrode current collector 233a excluding the negative electrode terminal tab.

[0223] Furthermore, in each of the above embodiments, examples of outer casings with different shapes have been described, but the shapes of the container body and the lid member may be changed as appropriate as long as the lid member can be welded to a container body formed in a bottomed cylindrical shape to close the opening of the container body. For example, the rigidity of the lid member may be improved by forming an annular groove with a U-shaped cross section in the lid member. Furthermore, the lid member may be formed in a cylindrical shape with a top, or the lid member 130 shown in FIG. 14 may be used upside down.

[0224] Furthermore, in each of the above embodiments, the container body and the sealing plate that constitute the exterior body do not necessarily have to be made of metal. For example, at least one of the container body and the sealing plate may be formed using a laminate film in which a metal layer made of stainless steel or the like and a film-like resin layer are laminated. Even in such a case, welding or the like can be performed using the metal layer. [Explanation of symbols]

[0225] O…Battery axis C: Center axis of support 1, 90, 100, 120, 140, 150, 170, 200...Secondary battery (electrochemical cell) 2...Exterior body 4...Shim member 5. Containment space 10...Container body 11...Bottom wall 12...Peripheral wall part 20, 110, 130, 160, ... Lid member (sealing plate) 21, 171...Through holes 30, 210, 220, 230...electrode body 40, 212, 222, 232...Positive electrodes 50, 213, 223, 233...Negative electrode 60...Sealant film (sealing material) 61...Current collecting plate 201...Strut part 211, 221...Separator

Claims

1. an exterior body including a container body formed in a cylindrical shape with a bottom, the container body having a bottom wall portion and a peripheral wall portion, and a sealing plate welded to the container body so as to close an opening of the container body, forming an accommodation space between the container body and the sealing plate; an electrode assembly having a positive electrode and a negative electrode and accommodated in the accommodation space; a shim member disposed in the housing space and sandwiched between the electrode body and at least one of the sealing plate and the bottom wall in the battery axis direction; a current collecting plate welded to the sealing plate or the bottom wall portion via an insulating sealant and at least a portion of which is exposed to the outside, the sealing plate is disposed so as to overlap the bottom wall portion in the battery axis direction via the electrode body and the shim member, one of the positive electrode and the negative electrode is electrically connected to the current collector plate, and the other electrode is electrically connected to the container body; the current collector plate is welded via the sealant to a lower surface of the sealing plate facing the storage space, and is partially exposed to the outside through a through hole formed so as to penetrate the sealing plate in the battery axial direction.

2. 10. The electrochemical cell of claim 1, The shim members are disposed between the sealing plate and the electrode body, and between the bottom wall portion and the electrode body.

3. 3. The electrochemical cell according to claim 1 or 2, The shim member is elastically deformable in the battery axial direction.

4. 4. The electrochemical cell according to claim 1, The shim member is formed of an insulating material.

5. 4. The electrochemical cell according to claim 1, The shim member is formed of a conductive material.

6. 6. The electrochemical cell according to claim 1, a support portion that is accommodated in the accommodation space along the battery axis direction and supports the sealing plate, The electrode assembly is an electrochemical cell in which the positive electrode and the negative electrode are stacked with a separator sandwiched between them and wound around a central axis of the support column.

7. 6. The electrochemical cell according to claim 1, The electrode assembly is an electrochemical cell in which the positive electrodes and the negative electrodes are alternately stacked in the battery axial direction with separators sandwiched therebetween.

8. an exterior body including a container body formed in a cylindrical shape with a bottom, the container body having a bottom wall portion and a peripheral wall portion, and a sealing plate welded to the container body so as to close an opening of the container body, forming an accommodation space between the container body and the sealing plate; an electrode assembly having a positive electrode and a negative electrode and accommodated in the accommodation space; a shim member disposed in the housing space and sandwiched between the electrode body and at least one of the sealing plate and the bottom wall in the battery axis direction; a current collector plate welded to the sealing plate or the bottom wall portion via an insulating sealant and at least a portion of which is exposed to the outside, a step of thermally welding a first sealant welded to the current collecting plate and a second sealant welded to the sealing plate to form the sealant consisting of the first sealant and the second sealant, and combining the current collecting plate and the sealing plate via the sealant; combining at least one of the sealing plate and the bottom wall portion with the shim member; a step of setting the electrode assembly in the storage space inside the container body; a step of combining the sealing plate with the container body so that the sealing plate overlaps the bottom wall portion in the battery axis direction via the electrode body and the shim member; a step of electrically connecting one of the positive electrode and the negative electrode to the current collector plate and electrically connecting the other electrode to the container body; and welding the sealing plate to the container body.

9. 9. The method for manufacturing an electrochemical cell according to claim 8, forming a through hole in the sealing plate in advance; a step of injecting an electrolyte into the housing space through the through hole after welding the container body and the sealing plate together; and sealing the through-hole after the injection of the electrolyte.

10. 10. The method for producing an electrochemical cell according to claim 8 or 9, a manufacturing method for an electrochemical cell, the method including: overlapping the current collector plate and the first sealing material, heating the current collector plate by laser irradiation or induction heating, and heating the first sealing material using the heat of the heated current collector plate, thereby combining the current collector plate and the first sealing material integrally.

11. 11. The method for manufacturing an electrochemical cell according to claim 8, a method for manufacturing an electrochemical cell, the method including: overlapping the sealing plate and the second sealant, heating the current collector plate by laser irradiation or induction heating, and using the heat from the heated current collector plate to heat the second sealant, thereby combining the sealing plate and the second sealant together.

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