Secondary battery manufacturing method and secondary battery

Abstract

To provide a method for manufacturing a secondary battery that is vibration resistant and has an electrolyte sufficiently permeated into the inside of an electrode assembly, and provide the secondary battery.SOLUTION: The technology disclosed herein relates to a method for manufacturing a secondary battery, and includes an assembly preparation step S10 of preparing an assembly in which current collecting terminals 33, 34 and an electrode body 20 are connected, an electrode body accommodation step S20 of accommodating the electrode body 20 inside a bag-shaped shrink pack 80 having an upper opening 80h, an electrolyte injection step S30 of injecting an electrolyte into the shrink pack 80, an electrolyte permeation step S40 of permeating the electrolyte into the electrode body 20, and a shrink pack heat shrinkage step S50 of heat-shrinking the shrink pack 80.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a secondary battery and a secondary battery.

Background Art

[0002] Secondary batteries are suitably used as drive power sources mounted on vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), and their demand is rapidly expanding. When a secondary battery is used, vibration may be applied from the outside. Therefore, secondary batteries are required to have resistance to external vibration (vibration resistance). As a technique for improving the vibration resistance of secondary batteries, for example, a technique such as that disclosed in Patent Document 1 can be cited. Patent Document 1 discloses a battery including a power generation element (electrode body), a positive electrode current collector (positive electrode current collecting terminal), a negative electrode current collector (negative electrode current collecting terminal), a non-aqueous electrolyte, and a battery case. And in Patent Document 1, it is described that the vibration resistance is improved by bundling the power generation element, the positive electrode current collector, and the negative electrode current collector with a shrink tube which is a seamless tube.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in Patent Document 1, after the shrink tube is heat-shrunk, the non-aqueous electrolyte is permeated. According to the study by the present inventor, in the above-described technique, since the electrode body is covered with the shrink tube, it becomes difficult to permeate the electrolyte inside the electrode body.

[0005] The technology disclosed herein has been made in view of the above circumstances, and aims to provide a method for manufacturing a secondary battery having vibration resistance and allowing an electrolytic solution to sufficiently penetrate into the electrode body, as well as a secondary battery.

Means for Solving the Problems

[0006] The technology disclosed herein relates to a method for manufacturing a secondary battery, which includes an assembly manufacturing step of manufacturing an assembly in which a current collector terminal and an electrode body are connected, an electrode body housing step of housing the electrode body inside a bag-shaped shrink pack having an upper opening, an electrolytic solution injection step of injecting an electrolytic solution inside the shrink pack, an electrolytic solution penetration step of allowing the electrolytic solution to penetrate into the electrode body, and a shrink pack heat shrinkage step of heat shrinking the shrink pack.

[0007] In the above manufacturing method, an electrolytic solution is injected inside the bag-shaped shrink pack, and the electrolytic solution is allowed to penetrate into the electrode body. Thereby, the electrolytic solution can penetrate into the electrode body. Then, by heat shrinking the shrink pack, the current collector terminal and the electrode body are fixed by the shrink pack. Thereby, it is possible to provide a secondary battery having vibration resistance and allowing the electrolytic solution to sufficiently penetrate into the electrode body.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0009] Hereinafter, with appropriate reference to the drawings, some preferred embodiments of the technology disclosed herein will be described. Matters other than those specifically mentioned in this specification and necessary for the implementation of the present disclosure (for example, the general configuration and manufacturing process of a secondary battery that do not characterize the present disclosure) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field.

[0010] In the following drawings, members and parts having the same function are denoted by the same reference numerals, and duplicate descriptions may be omitted or simplified. Also, the notation "A to B" indicating a range in this specification includes the meaning of "A or more and B or less", as well as the meaning of "preferably greater than A" and "preferably less than B". Further, in this specification, the "secondary battery" (hereinafter sometimes simply referred to as "battery") refers to all power storage devices capable of repeatedly performing charge and discharge by the movement of charge carriers between a positive electrode and a negative electrode through an electrolyte.

[0011] Hereinafter, after explaining the configuration of the secondary battery 100 disclosed herein, the manufacturing method of the secondary battery disclosed herein will be described. In the following description, the reference numerals L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, up, and down, respectively, and the reference numerals X, Y, and Z in the drawings represent the long side direction, the short side direction orthogonal to the long side direction, and the up-down direction orthogonal to the short side direction and the long side direction of the secondary battery 100, respectively. However, these directions are defined for the convenience of explanation and do not limit the installation mode of the secondary battery 100 in any way.

[0012] <Secondary Battery> FIG. 1 is a perspective view schematically showing a secondary battery 100 according to an embodiment. FIG. 2 is a schematic longitudinal sectional view taken along line II-II of FIG. 1. FIG. 3 is a schematic longitudinal sectional view taken along line III-III of FIG. 1. As shown in FIGS. 1 and 2, the secondary battery 100 includes a battery case 10, an electrode body 20, a positive current collector terminal 34, a negative current collector terminal 44, a shrink pack 80, and an electrolytic solution (not shown). The secondary battery 100 is characterized by including the shrink pack 80 disclosed herein, and other configurations may be the same as those of the prior art. Hereinafter, the specific configuration of the secondary battery 100 will be described.

[0013] The battery case 10 is a housing that houses the electrode body 20, the shrink pack 80, and the electrolytic solution. As shown in FIGS. 1 and 2, the battery case 10 has an outer shape that is flat, bottomed, and rectangular parallelepiped (square) here. As shown in FIG. 2, here, the battery case 10 includes an outer package 12 having an opening 12h, and a sealing plate (lid body) 14 that closes the opening 12h. The battery case 10 is preferably square. The material of the battery case 10 may be the same as that conventionally used, and there is no particular limitation. The battery case 10 is preferably made of metal, and more preferably made of, for example, aluminum, aluminum alloy, iron, iron alloy, or the like.

[0014] As shown in FIG. 1, the outer package 12 includes a bottom surface 12a, a pair of wide surfaces 12b that extend from the bottom surface 12a and face each other, and a pair of narrow surfaces 12c that extend from the bottom surface 12a and face each other here. The bottom surface 12a is substantially rectangular. The bottom surface 12a faces the opening 12h (see FIG. 2). The sealing plate 14 is attached to the outer package 12 so as to close the opening 12h of the outer package 12. The sealing plate 14 faces the bottom surface 12a of the outer package 12. The sealing plate 14 is substantially rectangular in plan view. The battery case 10 is integrated by joining (for example, welding) the sealing plate 14 to the periphery of the opening 12h of the outer package 12.

[0015] As shown in FIGS. 1 and 2, here, a gas discharge valve 17 is provided on the sealing plate 14. The gas discharge valve 17 is a thin-walled portion configured to break when the pressure in the battery case 10 reaches a predetermined value or more and discharge the gas in the battery case 10 to the outside. In this embodiment, the gas discharge valve 17 is provided on the sealing plate 14, but in other embodiments, the gas discharge valve 17 may be provided on the exterior body 12.

[0016] As shown in FIGS. 1 and 2, here, the positive electrode terminal 30 and the negative electrode terminal 40 are respectively attached to the sealing plate 14. Specifically, the positive electrode terminal 30 is attached to one end (the left end in FIG. 2) in the long side direction X of the sealing plate 14. The negative electrode terminal 40 is attached to the other end (the right end in FIG. 2) in the long side direction X of the sealing plate 14. In this embodiment, the positive electrode terminal 30 and the negative electrode terminal 40 are provided on the sealing plate 14, but in other embodiments, the positive electrode terminal 30 and the negative electrode terminal 40 may be provided on the exterior body 12.

[0017] As shown in FIG. 2, one end of the positive electrode terminal 30 is exposed on the outer surface of the battery case 10. On the other hand, the other end of the positive electrode terminal 30 is electrically connected to the electrode body 20 via the positive electrode current collector terminal 34 inside the battery case 10. One end of the negative electrode terminal 40 is exposed on the outer surface of the battery case 10. On the other hand, the other end of the negative electrode terminal 40 is electrically connected to the electrode body 20 via the negative electrode current collector terminal 44 inside the battery case 10. The positive electrode terminal 30 is preferably formed of a metal with excellent conductivity, such as aluminum or an aluminum alloy. Also, the negative electrode terminal 40 is preferably formed of a metal with excellent conductivity, such as copper or a copper alloy.

[0018] Here, the positive electrode terminal 30 and the negative electrode terminal 40 are insulated from the battery case 10 (here, the sealing plate 14) by a gasket (not shown) and an insulator (not shown), respectively. The gasket and the insulator can be composed of a resin material having electrical insulating properties, such as a fluorinated resin such as perfluoroalkoxyfluororesin (PFA), polytetrafluoroethylene (PTFE), polyphenylene sulfide resin (PPS), polypropylene (PP), or the like.

[0019] The positive electrode current collector terminal 34 is attached to the non-formed portion 52a of the positive electrode active material layer of the positive electrode current collector 52 and is a member that constitutes a conduction path for electrically connecting the positive electrode 50 and the positive electrode terminal 30. The material of the positive electrode current collector terminal 34 is not particularly limited, and a metal material that can be used for the current collector terminal of a conventional secondary battery can be used without particular limitation. The positive electrode current collector terminal 34 is preferably composed of a conductive metal of the same type as the positive electrode current collector 52, such as aluminum, an aluminum alloy, nickel, stainless steel, or the like. The positive electrode current collector terminal 34 is an example of the "current collector terminal" disclosed herein.

[0020] As shown in FIG. 2, the positive electrode current collector terminal 34 includes a long plate-shaped base portion extending in the vertical direction Z. One end portion of the positive electrode current collector terminal 34 (in FIG. 2, the lower end portion of the positive electrode current collector terminal 34) is electrically connected to the non-formed portion 52a of the positive electrode active material layer of the positive electrode current collector 52. The other end portion of the positive electrode current collector terminal 34 is electrically connected to the positive electrode terminal 30 inside the battery case 10.

[0021] The negative electrode current collector terminal 44 is attached to the non-formed portion 62a of the negative electrode active material layer of the negative electrode current collector 62 and is a member that constitutes a conduction path for electrically connecting the negative electrode 60 and the negative electrode terminal 40. The material of the negative electrode current collector terminal 44 is not particularly limited, and a metal material that can be used for the current collector terminal of a conventional secondary battery can be used without particular limitation. The negative electrode current collector terminal 44 is preferably composed of a conductive metal of the same type as the negative electrode current collector 62, such as copper, a copper alloy, nickel, stainless steel, or the like. The negative electrode current collector terminal 44 is an example of the "current collector terminal" disclosed herein.

[0022] As shown in FIG. 2, the negative electrode current collector terminal 44 includes a long plate-shaped base portion extending in the vertical direction Z. One end portion of the negative electrode current collector terminal 44 (the lower end portion of the negative electrode current collector terminal 44 in FIG. 2) is electrically connected to the non-negative electrode active material layer portion 62a of the negative electrode current collector 62. The other end portion of the negative electrode current collector terminal 44 is electrically connected to the negative electrode terminal 40 inside the battery case 10.

[0023] As shown in FIG. 2, here, the positive electrode current collector terminal 34 has a recess 34r extending inward from the outer surface (the left side in FIG. 2) of the positive electrode current collector terminal 34. The recess 34r is arranged to face a shrink pack 80 described later. On the other hand, the negative electrode current collector terminal 44 has a recess 44r extending inward from the outer surface (the right side in FIG. 2) of the negative electrode current collector terminal 44. The recess 44r is arranged to face the shrink pack 80 described later. In some preferred embodiments, it is preferable that the current collector terminals (the positive electrode current collector terminal 34 and the negative electrode current collector terminal 44) have recesses extending inward from the outer surfaces of the current collector terminals. The recesses 34r and 44r are examples of the "recesses extending inward from the outer surfaces of the current collector terminals" disclosed herein. The shrink pack 80 described later is arranged so as to cover at least a part of the recesses 34r and 44r respectively. Thereby, the shrink pack 80 and the positive electrode current collector terminal 34, and the shrink pack 80 and the negative electrode current collector terminal 44 are preferably fixed. In other words, it is possible to preferably prevent the shrink pack 80 from shifting during use of the secondary battery 100. However, the recesses 34r and 44r are not essential, and in other embodiments, the positive electrode current collector terminal 34 and the negative electrode current collector terminal 44 may not have recesses. Also, either the positive electrode current collector terminal 34 or the negative electrode current collector terminal 44 may have the recesses 34r and 44r.

[0024] As shown in FIG. 2, in the present embodiment, the shapes of the recesses 34r and 44r are rectangular. However, the shapes of the recesses 34r and 44r are not limited thereto. For example, the shapes of the recesses 34r and 44r may be V-shaped, U-shaped, semi-circular, or the like.

[0025] The maximum depth of the recesses 34r and 44r (here, the maximum value of the depth from the outer surface of the positive current collector terminal 34 to the recess 34r when viewed in the X direction. Or, the maximum value of the depth from the outer surface of the negative current collector terminal 44 to the recess 44r.) is, for example, 1 mm or more, preferably 1.5 mm or more, and more preferably 2 mm or more. Thereby, the shrink pack 80 can be suitably fixed to the positive current collector terminal 34 and the negative current collector terminal 44. On the other hand, from the viewpoint of ensuring the strength of the positive current collector terminal 34 and the negative current collector terminal 44, the maximum depth h1 of the recesses 34r and 44r is, for example, 1 / 2 or less, preferably 1 / 3 or less, and more preferably 1 / 4 or less with respect to the width of the positive current collector terminal 34 and the negative current collector terminal 44.

[0026] As shown in FIG. 2, in the present embodiment, one recess 34r and 44r is formed on the outer surface of the positive current collector terminal 34 and the negative current collector terminal 44, respectively. However, it is not limited thereto. A plurality of recesses 34r and 44r may be formed on the outer surface of the positive current collector terminal 34 and the negative current collector terminal 44. Further, the recesses 34r and 44r are preferably arranged at positions on the outer surfaces of the positive current collector terminal 34 and the negative current collector terminal 44 such that at least a part of the shrink pack 80 after heat shrinkage is covered by the recesses 34r and 44r.

[0027] The electrode body 20 is a power generation element of the secondary battery 100. As shown in FIG. 2, the electrode body 20 has openings 20h at both ends in the width direction (Y direction in FIG. 2). The electrode body 20 is disposed inside the battery case 10 in a state where the outer surface of the electrode body 20 is covered (coated) with a shrink pack 80 described later. As shown in FIG. 3, in the present embodiment, one electrode body is accommodated inside the battery case 10. However, the number of electrode bodies 20 accommodated inside one battery case 10 is not particularly limited, and a plurality (two or more) of electrode bodies 20 may be accommodated in a state where each is covered with a shrink pack 80.

[0028] The electrode body 20 is, in this case, a flat wound electrode body formed by overlapping a strip-shaped positive electrode 50 and a strip-shaped negative electrode 60 with two strip-shaped separators 70 interposed therebetween and winding them in the longitudinal direction. However, the electrode body may be a laminated electrode body in which a rectangular positive electrode and a rectangular negative electrode are alternately laminated with a rectangular separator interposed therebetween. Further, the electrode body may be a zigzag laminated electrode body formed by sandwiching a plurality of positive electrodes and a plurality of negative electrodes between separators folded in a zigzag shape. In some preferred embodiments, the electrode body 20 is preferably a wound electrode body.

[0029] The positive electrode 50 has a strip-shaped positive electrode current collector 52 and a positive electrode active material layer 54 fixed on at least one surface of the positive electrode current collector 52. As shown in FIG. 2, here, the positive electrode 50 has a configuration in which the positive electrode active material layer 54 is formed along the longitudinal direction on one side or both sides (here, both sides) of the long positive electrode current collector 52. Here, the non-positive electrode active material layer portion 52a (that is, the portion where the positive electrode current collector 52 is exposed without the positive electrode active material layer 54 being formed) is formed so as to protrude outward from the left end in the winding axis direction of the electrode body 20 (that is, the sheet width direction orthogonal to the longitudinal direction).

[0030] For each member constituting the positive electrode 50, conventionally known materials that can be used in a general battery (for example, a lithium-ion secondary battery) can be used without particular limitation. For example, the positive electrode current collector 52 is preferably made of a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The positive electrode active material layer 54 contains a positive electrode active material (for example, a lithium transition metal composite oxide such as lithium nickel cobalt manganese composite oxide) that can reversibly occlude and release charge carriers. Note that the positive electrode active material layer 54 may contain optional components other than the positive electrode active material, such as a conductive material, a binder, and various additive components. As the conductive material, for example, a carbon material such as acetylene black (AB) can be used. As the binder, for example, polyvinylidene fluoride (PVdF) can be used.

[0031] The negative electrode 60 includes a strip-shaped negative electrode current collector 62 and a negative electrode active material layer 64 fixed on at least one surface of the negative electrode current collector 62. As shown in FIG. 2, here the negative electrode 60 has a configuration in which the negative electrode active material layer 64 is formed along the longitudinal direction on one side or both sides (here both sides) of the long negative electrode current collector 62. Here, a non-negative electrode active material layer formation portion 62a (that is, a portion where the negative electrode current collector 62 is exposed without the formation of the negative electrode active material layer 64) is formed so as to protrude outward from the right end in the winding axis direction of the electrode body 20 (that is, the sheet width direction orthogonal to the longitudinal direction).

[0032] For each member constituting the negative electrode 60, conventionally known materials that can be used in a general battery (for example, a lithium ion secondary battery) can be used without particular limitation. For example, the negative electrode current collector 62 is preferably composed of a conductive metal such as copper, a copper alloy, nickel, or stainless steel. The negative electrode active material layer 64 contains a negative electrode active material (for example, a carbon material such as graphite) that can reversibly occlude and release charge carriers. Note that the negative electrode active material layer 64 may contain optional components other than the negative electrode active material, such as a conductive material, a binder, a dispersant, a thickener, and various additive components. As the binder, for example, rubbers such as styrene butadiene rubber (SBR) can be used. As the dispersant, for example, celluloses such as carboxymethyl cellulose (CMC) can be used.

[0033] The separator 70 is a member that insulates the positive electrode active material layer and the negative electrode active material layer. As the separator 70, for example, a porous resin sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is suitable. A heat resistance layer (HRL) containing an inorganic filler may be provided on the surface of the separator 70. As the inorganic filler, for example, alumina, boehmite, aluminum hydroxide, titania, etc. can be used.

[0034] The electrolytic solution is accommodated inside the shrink pack 80 together with the electrode body 20. Typically, the electrolytic solution penetrates inside the electrode body 20 (between the positive electrode 50 and the negative electrode 60). However, it is not necessary for all of the electrolytic solution to penetrate inside the electrode body 20, and a part of the electrolytic solution may exist outside the electrode body 20 as surplus electrolytic solution. In that case, typically the surplus electrolytic solution exists between the shrink pack 80 and the outer surface of the electrode body 20. The electrolytic solution may be the same as that of a general secondary battery and is not particularly limited. The electrolytic solution is typically a non-aqueous liquid electrolyte (non-aqueous electrolytic solution) containing a non-aqueous solvent and a supporting salt. The non-aqueous solvent includes, for example, carbonates such as ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC). The non-aqueous solvent is preferably a mixture of EC, EMC, and DMC in the range of 1 to 99% respectively so that the total ratio is 100%. As the supporting salt, for example, a fluorine-containing lithium salt or the like can be used. The fluorine-containing lithium salt preferably includes lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (F2LiNO4S2) called LiFSI, or a mixture thereof. The concentration of the supporting salt is preferably 0.6 to 1.8 mol per 1 L of the non-aqueous solvent.

[0035] The shrink pack 80 is housed inside the battery case 10 together with the electrode body 20. The shrink pack 80 is disposed between the battery case 10 and the electrode body 20. As shown in FIG. 3, the shrink pack 80 is, here, a bottomed member capable of housing the electrode body 20. As shown in FIG. 3, the shrink pack 80 covers the outer surface of the electrode body 20 by thermally shrinking itself. The shrink pack 80 is disposed so as to cover the openings 20h (the left end and the right end in FIG. 2) at both ends of the electrode body 20. Further, the shrink pack 80 is disposed so as to cover a part of the positive current collector terminal 34 and the negative current collector terminal 44. Thereby, the electrode body 20, the positive current collector terminal 34, and the negative current collector terminal 44 are respectively fixed. As shown in FIGS. 2 and 3, here, the shrink pack 80 has an opening 80h at the upper end. The opening 80h of the shrink pack 80 may be left as it is or may be in a sealed state by heat sealing or the like. As shown in FIG. 3, here, the opening 80h of the shrink pack 80 is not sealed. When a laminated electrode body is used as the electrode body 20, it is preferable to seal the opening 80h of the shrink pack 80. Thereby, the electrolytic solution inside the electrode body 20 can be suitably retained. However, it is not necessary to completely seal the opening 80h of the shrink pack 80. From the viewpoint of allowing the gas generated during the use of the secondary battery 100 to escape to the outside of the shrink pack 80, it is preferable that at least a part of the opening 80h is not sealed. For example, among the opening 80h, the portions where the positive current collector terminal 34 and the negative current collector terminal 44 are covered by the shrink pack 80 may not be sealed.

[0036] As the shrink pack 80, for example, a heat-shrinkable resin such as polyethylene (PE), polypropylene (PP), polyolefin, polyvinyl chloride (PVC), polyethylene terephthalate (PET), or fluorinated resin can be adopted. Among them, PET can be suitably used as the shrink pack 80.

[0037] The secondary battery 100 disclosed herein includes a shrink pack 80 that covers the outer surface of the electrode body 20, thereby enabling the retention of the electrolytic solution within the electrode body 20. Specifically, during the use of the secondary battery 100, due to temperature conditions, SOC (State of Charge) conditions, etc., the electrode body 20 may expand and contract in the thickness direction. Due to such expansion and contraction, the electrolytic solution present inside the electrode body 20 may be pushed out from the opening 20h of the electrode body 20 to the outside of the electrode body 20, and there is a risk that a sufficient amount of the electrolytic solution cannot be retained inside the electrode body 20. Here, in the secondary battery 100 of the present embodiment, the opening 20h of the electrode body 20 is covered by the shrink pack 80. Therefore, even when expansion and contraction of the electrode body 20 occur, it is possible to prevent the electrolytic solution inside the electrode body 20 from flowing out to the outside.

[0038] Moreover, in the secondary battery 100 disclosed herein, the electrode body 20, the positive electrode current collector terminal 34, and the negative electrode current collector terminal 44 are respectively fixed by the shrink pack 80. Thereby, for example, even when vibration or impact (external force) is applied during the use of the secondary battery 100, movement of the electrode body 20 inside the battery case 10 can be suppressed, and damage to the electrode body 20 can be suppressed. Further, when the secondary battery 100 includes the recesses 34r and 44r, the shrink pack 80, the positive electrode current collector terminal 34, and the negative electrode current collector terminal 44 are more securely fixed. During the use of the secondary battery 100, displacement of the shrink pack 80 can be further suppressed.

[0039] The secondary battery 100 can be used for various applications. Suitable applications include power sources for driving mounted on vehicles such as battery electric vehicles (BEV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (PHEV). Further, the secondary battery 100 can be used as a storage battery such as a small power storage device. The secondary battery 100 can typically also be used in the form of a battery pack formed by connecting a plurality of them in series and / or in parallel.

[0040] Note that, as an example, a rectangular secondary battery 100 including an electrode body 20 having a flat winding structure has been described. However, the secondary battery disclosed herein is not limited to such a shape. For example, also, the secondary battery according to the present embodiment can be constructed in the form of a cylindrical secondary battery, a coin-type secondary battery, or the like.

[0041] <Method for manufacturing a secondary battery> Next, a method for manufacturing the secondary battery 100 disclosed herein will be described. FIG. 4 is a flowchart showing a method for manufacturing the secondary battery 100 according to an embodiment. The manufacturing method disclosed herein includes an assembly manufacturing step S10, an electrode body housing step S20, an electrolytic solution injection step S30, an electrolytic solution penetration step S40, and a shrink pack heat shrinkage step S50. Note that the manufacturing method disclosed herein is characterized by the electrolytic solution injection step and the shrink pack heat shrinkage step, and the other manufacturing processes may be the same as those in the prior art. Also, other steps may be included at any stage. Also, since the materials used for manufacturing the secondary battery 100 can be those described above, redundant descriptions are omitted here.

[0042] (Assembly manufacturing step S10) In the assembly manufacturing step S10, an assembly in which a current collector terminal and an electrode body are connected is manufactured. Note that, in this specification, the "assembly" refers to a structure having a current collector terminal and an electrode body. The assembly manufactured in the present embodiment includes a positive current collector terminal 34, a negative current collector terminal 44, and an electrode body 20.

[0043] In the assembly manufacturing step S10, as shown in FIG. 2, the positive current collector exposed portion (positive electrode active material layer non-formation portion 52a) of the electrode body 20 and the positive current collector terminal 34 are joined. On the other hand, the negative current collector exposed portion (negative electrode active material layer non-formation portion 62a) of the electrode body 20 and the negative current collector terminal 44 are joined. Such joining can be performed by, for example, a conventionally known method (for example, ultrasonic joining, resistance welding, laser welding, etc.). Thereby, the electrode body 20, the positive current collector terminal 34, and the negative current collector terminal 44 are integrated.

[0044] Although not limited thereto, in the present embodiment, after the assembly manufacturing step S10, the assembly manufactured above and the sealing plate 14 can be further integrated. Specifically, first, a sealing plate 14 to which a positive electrode terminal 30 and a negative electrode terminal 40 are attached is prepared (see FIG. 5). Then, the positive electrode terminal 30 and the positive electrode current collecting terminal 34, and the negative electrode terminal 40 and the negative electrode current collecting terminal 44 are joined by a conventionally known method (for example, ultrasonic bonding, resistance welding, laser welding, etc.). As a result, the positive electrode terminal 30 is electrically connected to the electrode body 20 via the positive electrode current collecting terminal 34. Also, the negative electrode terminal 40 is electrically connected to the electrode body 20 via the negative electrode current collecting terminal 44. Also, as a result, the assembly and the sealing plate 14 are integrated. However, the connection between the positive electrode terminal 30 and the positive electrode current collecting terminal 34, and the negative electrode terminal 40 and the negative electrode current collecting terminal 44 does not need to be performed immediately after the assembly manufacturing step S10, and can be performed at any timing as long as it is before the sealing plate 14 is sealed to the outer body 12.

[0045] (Electrode body accommodation step S20) In the electrode body accommodation step S20, the electrode body 20 is accommodated inside a bag-shaped shrink pack 80 having an opening 80h at the top. The electrode body 20 is in a state of an assembly joined to the positive electrode current collecting terminal 34 and the negative electrode current collecting terminal 44 through the assembly manufacturing step.

[0046] FIG. 5 is a schematic diagram for explaining the state of the electrode body accommodation step S20 according to an embodiment. As shown in FIG. 5, in the present embodiment, the positive electrode current collecting terminal 34 and the negative electrode current collecting terminal 44 are integrated with the sealing plate 14 via the positive electrode terminal 30 and the negative electrode terminal 40.

[0047] The shrink pack 80 prepared in the electrode body accommodation step S20 (that is, the shrink pack 80 before the shrink pack heat shrinkage step) is typically a bag-shaped member having an opening 80h at the top. In the present specification, "bag-shaped" indicates a bottomed shape capable of accommodating an electrolytic solution, and includes, for example, a bottomed cylindrical shape, a shape having a flange portion at the bottom, a box shape, etc. As shown in FIG. 5, here, the shrink pack 80 is bottomed cylindrical.

[0048] In the electrode body housing step S20, the electrode body 20 is housed through the opening 80h of the shrink pack 80. As shown in FIG. 5, at this time, the electrode body 20 is arranged such that the openings 20h at both ends of the electrode body 20 face the shrink pack 80. Here, the electrode body 20 is arranged such that the width direction of the opening 80h of the shrink pack 80 and the winding axis of the electrode body 20 are substantially parallel. A part including the connection portion with the electrode body 20 of the positive current collector terminal 34 and the negative current collector terminal 44 is housed in the shrink pack 80 together with the electrode body 20. On the other hand, a part of the positive current collector terminal 34 and the negative current collector terminal 44 is arranged to be exposed upward from the opening 80h of the shrink pack 80. When the positive current collector terminal 34 and the negative current collector terminal 44 have recesses 34r and 44r, it is preferable to house the positive current collector terminal 34 and the negative current collector terminal 44 such that the opening 80h of the shrink pack 80 is above the upper ends of the recesses 34r and 44r (in other words, so as to cover the recesses 34r and 44r). Thereby, in the subsequent shrink pack heat shrinkage step, it becomes easier to cover the recesses 34r and 44r with the shrink pack 80.

[0049] The dimensions and shape of the shrink pack 80 prepared in the electrode body housing step S20 are not particularly limited because they can be appropriately adjusted according to the size of the electrode body 20, the shape of the battery case 10, etc. The shrink pack 80 before heat shrinkage preferably has a dimensional allowance (clearance) when housing the electrode body 20. Thereby, it becomes easier to house the electrode body 20 in the shrink pack 80. Also, in the electrolyte penetration step S40 described later, it becomes easier for the electrolyte to penetrate into the electrode body 20.

[0050] The thickness of the shrink pack 80 before heat shrinkage can be adjusted, for example, according to the size of the electrode body 20, the amount of electrolyte injection, and the resin constituting the shrink pack 80. From the viewpoint of giving sufficient strength to the strength of the shrink pack 80 after heat shrinkage, it is preferably 30 μm or more, more preferably 50 μm or more. On the other hand, from the viewpoint of the production efficiency of the secondary battery 100, etc., the thickness of the shrink pack 80 before heat shrinkage is preferably 200 μm or less, more preferably 150 μm or less.

[0051] (Electrolyte injection step S30) In the electrolyte injection step S30, the electrolyte is injected into the shrink pack 80 from the opening 80h of the shrink pack 80. As a result, compared with the case of directly injecting the electrolyte into the battery case 10, even with a small injection amount of the electrolyte, the electrolyte can penetrate into the electrode body 20 by the subsequent electrolyte penetration step S40. The electrolyte injection step S30 may be performed at atmospheric pressure, or may be performed, for example, in a reduced pressure environment such as inside a chamber with adjustable pressure.

[0052] The electrolyte injection step S30 is preferably performed after the electrode body accommodation step S20 (that is, in a state where the electrode body 20 is accommodated in the shrink pack 80 before heat shrinkage). However, it is not limited to this, and the electrolyte injection step S30 may be performed at the timing before the electrode body accommodation step S20 (that is, in a state where the electrode body 20 is not accommodated in the shrink pack 80 before heat shrinkage).

[0053] (Electrolyte penetration step S40) In the electrolyte penetration step S40, the electrolyte is made to penetrate into the electrode body 20 accommodated inside the shrink pack 80. Here, the shrink pack 80 is in a state before heat shrinkage. That is, it is a state before the opening 20h of the electrode body 20 is covered by the shrink pack 80. Therefore, it becomes easier for the electrolyte to penetrate from the opening 20h of the electrode body 20.

[0054] In the electrolyte penetration step S40, it is preferable to accommodate the electrode body 20 accommodated inside the shrink pack 80 in a chamber with adjustable pressure and perform it under reduced pressure conditions. As a result, the inside of the electrode body 20 (between the positive electrode 50 and the negative electrode 60) becomes negative pressure, and the electrolyte is sucked into the inside of the electrode body 20 that has become negative pressure. Therefore, the electrolyte can be efficiently penetrated to the inside of the electrode body 20. Also, the time required for the electrolyte penetration step S40 can be shortened.

[0055] When performing the electrolytic solution penetration step S40 under reduced pressure conditions, the internal pressure in the chamber is preferably -50 kPa or less, more preferably -80 kPa or less. Thereby, the time required for the electrolytic solution penetration step S40 can be shortened. On the other hand, when evacuating the inside of the decompression chamber, the lower limit value of the pressure during the decompression process is not particularly limited as long as the decompression chamber does not break. For example, the lower limit value of the pressure inside the decompression chamber may be -100 kPa or more.

[0056] Note that the decompression treatment in the electrolytic solution penetration step S40 is not essential, and it is not necessary to continue the decompression treatment. For example, in the electrolytic solution penetration step S40, in addition to the decompression treatment, a pressurization treatment may be repeatedly performed. Thereby, the penetration of the electrolytic solution into the electrode body 20 can be promoted.

[0057] When performing a pressurization treatment in the electrolytic solution penetration step S40, the internal pressure in the chamber is preferably 0.5 MPa or more, more preferably 0.8 MPa or more. On the other hand, the upper limit value of the pressure during the pressurization treatment may be, for example, 1.0 MPa or less.

[0058] Note that after the electrolytic solution penetration step S40, the opening 80h of the shrink pack 80 may be sealed by heat sealing or the like. Thereby, the electrolytic solution is likely to be retained inside the shrink pack 80. In addition, the displacement of the shrink pack 80 can be more preferably suppressed. Note that it is not necessary to completely seal the opening 80h of the shrink pack 80, and only a part of the opening 80h may be sealed. Also, sealing may be performed discontinuously. However, the sealing of the shrink pack 80 is not essential and can be omitted.

[0059] (Shrink Pack Heat Shrinkage Step S50) In the shrink-pack heat shrinkage step S50, the shrink pack 80 is heat-shrunk. As a result, the shrink pack 80 shrinks and is arranged to cover the outer surface of the electrode body 20. Further, by such a process, the openings 20h at both ends of the electrode body 20 are covered with the shrink pack 80. Also, the electrode body 20, the positive current collector terminal 34, and the negative current collector terminal 44 are fixed by the shrink pack 80. Thereby, the vibration resistance and shock resistance of the secondary battery 100 can be obtained.

[0060] The method of heat-shrinking the shrink pack 80 is not particularly limited, and a conventionally known method can be adopted. For example, the shrink pack 80 containing the electrode body 20, the positive current collector terminal 34, and the negative current collector terminal 44 is passed through a shrink furnace. Then, heat shrinkage can be achieved by heating at a temperature equal to or higher than the shrinkage temperature of the shrink pack 80 in the shrink furnace.

[0061] When the positive current collector terminal 34 and the negative current collector terminal 44 have recesses, for example, as shown in FIG. 2, it is preferable to heat-shrink the shrink pack 80 such that at least a part of the heat-shrunk shrink pack 80 covers the recesses 34r and 44r, respectively. In other words, it is preferable to heat-shrink the shrink pack 80 such that at least a part of the shrink pack 80 is hooked on the recesses 34r and 44r. Thereby, the shrink pack 80, the positive current collector terminal 34, and the negative current collector terminal 44 are more firmly fixed. Therefore, displacement of the shrink pack 80 during use of the manufactured secondary battery 100 can be further suppressed.

[0062] After the shrink-pack heat shrinkage process S50, the assembly can be housed inside the exterior body 12, and the secondary battery 100 can be manufactured by sealing the sealing plate 14. For example, in the case of the present embodiment, the electrode body 20 integrated with the sealing plate 14 is inserted through the opening 12h of the exterior body 12. Then, the peripheries of the sealing plate 14 and the opening 12h of the exterior body 12 are joined by laser welding or the like. Thereby, the battery case 10 is sealed. Also, the electrode body 20 is fixed to the battery case 10 via the positive current collector terminal 34 and the negative current collector terminal 44. However, the method of housing such an assembly and the method of sealing the sealing plate 14 may be implemented by conventionally known means and do not characterize the manufacturing method of the secondary battery disclosed herein.

[0063] As described above, the preferred embodiments of the present disclosure have been explained, but the above embodiments are merely examples. The present disclosure can be implemented in various other forms. The present disclosure can be implemented based on the content disclosed in this specification and the common general knowledge in the art. The technology described in the claims includes various modifications and changes of the embodiments exemplified above. For example, it is also possible to replace a part of the above-described embodiments with other modified examples, and it is also possible to add other modified examples to the above-described embodiments. Also, if the technical features are not described as essential, they can be appropriately deleted.

[0064] <First Modified Example> FIG. 6 is a diagram corresponding to FIG. 2 of the secondary battery 200 according to the first modified example. In the secondary battery 200 according to the first modified example, a positive current collector terminal 134 is provided instead of the positive current collector terminal 34. Also, in the secondary battery 200 according to the first modified example, a negative current collector terminal 144 is provided instead of the negative current collector terminal 44. The secondary battery 200 may have the same configuration as the above-described secondary battery 100 except for the above points.

[0065] As shown in FIG. 6, the positive electrode current collecting terminal 134 and the negative electrode current collecting terminal 144 are each provided with convex portions 134p and 144p instead of the concave portions 34r and 44r. The convex portion 134p is formed so as to project outward from the outer surface (the left side in FIG. 6) of the positive electrode current collecting terminal 134. On the other hand, the convex portion 144p is formed so as to project outward from the outer surface (the right side in FIG. 6) of the negative electrode current collecting terminal 144. The convex portions 134p and 144p are arranged so as to face the shrink pack 80 described later respectively. Here, at least a part of the convex portions 134p and 144p is arranged so as to be covered by the shrink pack 80 after heat shrinkage. Thereby, the shrink pack 80 and the positive electrode current collecting terminal 134, and the shrink pack 80 and the negative electrode current collecting terminal 144 are more reliably fixed. In other words, the displacement of the shrink pack 80 can be more suppressed when the secondary battery 200 is in use. As shown in FIG. 6, here, the positive electrode current collecting terminal 134 and the negative electrode current collecting terminal 144 each have convex portions 134p and 144p. However, either the positive electrode current collecting terminal 134 or the negative electrode current collecting terminal 144 may have the convex portions 134p and 144p. The convex portions 134p and 144p are an example of the "convex portion projecting outward from the outer surface of the current collecting terminal" disclosed herein.

[0066] As shown in FIG. 6, the shapes of the convex portions 134p and 144p according to the first modification are rectangular. However, the shapes of the convex portions 134p and 144p are not limited thereto. For example, the shapes of the convex portions 134p and 144p may be V-shaped, U-shaped, semi-circular, or the like.

[0067] The maximum height of the convex portions 134p and 144p (here, the maximum value of the height from the outer surface of the positive electrode current collecting terminal 134 to the convex portion 134p as viewed in the X direction. Or the maximum value of the height from the outer surface of the negative electrode current collecting terminal 144 to the convex portion 144p.) is, for example, 1 mm or more, preferably 3 mm or more, and more preferably 4 mm or more. Thereby, the shrink pack 80 can be suitably fixed to the positive electrode current collecting terminal 134 and the negative electrode current collecting terminal 144. On the other hand, from the viewpoint of interference with the inner surface of the battery case 10, the maximum height of the convex portions 134p and 144p is, for example, 20 mm or less, preferably 15 mm or less, and more preferably 10 mm or less.

[0068] As shown in FIG. 6, one convex portion 134p and 134p according to the first modification example is formed on each of the outer surfaces of the positive electrode current collector terminal 134 and the negative electrode current collector terminal 144. However, the present invention is not limited to this. A plurality of convex portions 134p and 144p may be formed on the outer surfaces of the positive electrode current collector terminal 134 and the negative electrode current collector terminal 144. Further, in addition to the convex portions 134p and 144p on the outer surfaces of the positive electrode current collector terminal 134 and the negative electrode current collector terminal 144, recesses such as the above-described recesses 34r and 44r may be further formed.

[0069] The manufacturing method of the secondary battery 200 according to the first modification example can be manufactured by the same method as the secondary battery 100 described above.

[0070] In the manufacturing method of the secondary battery 200 according to the first modification example, in the electrode body housing step S20, it is preferable to house the positive electrode current collector terminal 134 and the negative electrode current collector terminal 144 so that the opening 80h of the shrink pack 80 is above the upper end portions of the convex portions 134p and 144p (in other words, so as to cover the convex portions 134p and 144p). Thereby, in the shrink pack heat shrinkage step S50, it becomes easier to cover the convex portions 134p and 144p with the shrink pack.

[0071] In the manufacturing method of the secondary battery 200 according to the first modification example, in the shrink pack heat shrinkage step S50, it is preferable to heat-shrink the shrink pack 80 such that at least a part of the heat-shrunk shrink pack 80 covers the convex portions 134p and 144p respectively. In other words, it is preferable to heat-shrink the shrink pack 80 so that at least a part of the shrink pack 80 is hooked on the convex portions 134p and 144p. Thereby, the shrink pack 80, the positive electrode current collector terminal 134, and the negative electrode current collector terminal 144 are fixed more firmly. Therefore, it is possible to further suppress the displacement of the shrink pack 80 when the manufactured secondary battery 200 is in use.

[0072] As described above, specific aspects of the technology disclosed herein include those described in the following items. Step 1: An assembly manufacturing step of manufacturing an assembly in which a current collector terminal and an electrode body are connected; an electrode body housing step of housing the electrode body inside a bag-shaped shrink pack having an upper opening; an electrolytic solution injection step of injecting an electrolytic solution inside the shrink pack; an electrolytic solution penetration step of allowing the electrolytic solution to penetrate inside the electrode body; and a shrink pack heat shrinkage step of heat shrinking the shrink pack. A method for manufacturing a secondary battery comprising these steps. Step 2: The method for manufacturing a secondary battery according to Step 1, wherein the electrode body is housed in a chamber whose pressure can be adjusted, and the electrolytic solution penetration step is performed under reduced pressure conditions. Step 3: The current collector terminal has a recess that extends inward from the outer surface of the current collector terminal. In the shrink pack heat shrinkage step, the shrink pack is heat shrunk such that the shrink pack covers the recess. The method for manufacturing a secondary battery according to Step 1 or 2. Step 4: The current collector terminal has a protrusion that extends outward from the outer surface of the current collector terminal. In the shrink pack heat shrinkage step, the shrink pack is heat shrunk such that the shrink pack covers the protrusion. The method for manufacturing a secondary battery according to any one of Steps 1 to 3. Step 5: A secondary battery comprising: an electrode body having openings at both ends in the width direction; an electrolytic solution that has penetrated inside the electrode body; a battery case that houses the electrode body; a terminal attached to the battery case; a current collector terminal that connects the electrode body and the terminal; and a shrink pack that covers the outer surface of the electrode body. The shrink pack is arranged so as to cover the openings of the electrode body. Step 6: The current collector terminal has a recess that extends inward from the outer surface of the current collector terminal. The shrink pack is arranged so as to cover the recess. The secondary battery according to Step 5. Step 7: The current collector terminal has a protrusion that extends outward from the outer surface of the current collector terminal. The shrink pack is arranged so as to cover the protrusion. The secondary battery according to Step 5 or 6. Step 8: The electrode body is a wound electrode body in which a positive electrode and a negative electrode are wound with a separator therebetween. The secondary battery according to any one of Steps 5 to 7.

Description of Reference Numerals

[0073] 10 Battery case 12 Exterior body 14 Sealing plate 17 Gas discharge valve 20 Electrode body 20h (Opening of the electrode body) 30 Positive electrode terminal 34, 134 Positive current collector terminal 34r Recess 40 Negative electrode terminal 44, 144 Negative current collector terminal 44r Recess 50 Positive electrode 52 Positive current collector 52a Non-formation part of the positive electrode active material layer 54 Positive electrode active material layer 60 Negative electrode 62 Negative current collector 62a Non-formation part of the negative electrode active material layer 64 Negative electrode active material layer 70 Separator 80 Shrink pack 80h (Opening of the shrink pack) 100, 200 Secondary battery 134p Protrusion 144p Protrusion

Claims

1. An assembly manufacturing step of manufacturing an assembly in which a current collector terminal and an electrode body are connected, An electrode body housing step of housing the electrode body inside a bag-shaped shrink pack having an upper opening, An electrolytic solution injection step of injecting an electrolytic solution into the shrink pack, An electrolytic solution penetration step of allowing the electrolytic solution to penetrate into the electrode body, A shrink pack heat shrinkage step of heat shrinking the shrink pack, and comprising A method for manufacturing a secondary battery.

2. The electrode body is housed in a chamber with adjustable pressure, and the electrolytic solution penetration step is performed under reduced pressure conditions, The method for manufacturing a secondary battery according to Claim 1.

3. The current collector terminal has a recess extending inward from the outer surface of the current collector terminal, In the shrink pack heat shrinkage step, the shrink pack is heat shrunk such that the shrink pack covers the recess, The method for manufacturing a secondary battery according to Claim 1 or 2.

4. The current collector terminal has a protrusion extending outward from the outer surface of the current collector terminal, In the shrink pack heat shrinkage step, the shrink pack is heat shrunk such that the shrink pack covers the protrusion, The method for manufacturing a secondary battery according to Claim 1 or 2.

5. An electrode body having openings at both ends in the width direction, The electrolytic solution that has penetrated into the electrode body, A battery case that houses the electrode body, A terminal attached to the battery case, A current collector terminal that connects the electrode body and the terminal, A shrink pack that covers the outer surface of the electrode body, and comprising The shrink pack is arranged to cover the opening of the electrode body. Secondary battery.

6. The current collector terminal has a recess that extends inward from the outer surface of the current collector terminal. The shrink pack is arranged to cover the recess. The secondary battery according to claim 5.

7. The current collector terminal has a protrusion that extends outward from the outer surface of the current collector terminal. The shrink pack is arranged to cover the protrusion. The secondary battery according to claim 5.

8. The electrode body is a wound electrode body in which a positive electrode and a negative electrode are wound with a separator interposed therebetween. The secondary battery according to any one of claims 5 to 7.

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