Secondary battery manufacturing method and secondary battery

Abstract

The purpose of the present invention is to provide: a method for manufacturing a secondary battery which has vibration resistance and in which the interior of an electrode body is sufficiently impregnated with an electrolyte; and a secondary battery. The technology disclosed herein pertains to a method for manufacturing a secondary battery, the method being characterized by comprising: an assembly manufacturing step (S10) for manufacturing an assembly in which collector terminals (33, 34) and an electrode body (20) are connected; an electrode body housing step (S20) in which the electrode body (20) is housed inside a bag-shaped shrink bag (80) having an upper opening (80h); an electrolyte injection step (S30) in which an electrolyte is injected into the shrink package (80); an electrolyte solution permeation step (S40) in which the interior of the electrode body (20) is permeated with an electrolyte solution; and a shrink packet thermal shrinkage step (S50) in which the shrink packet (80) is thermally shrunk.

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 suitable for use as driving power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), and the demand for them is rapidly expanding. When a secondary battery is in use, vibration may be applied from the outside. Therefore, in a secondary battery, resistance to external vibration (vibration resistance) is required. As a technique for improving the vibration resistance of a secondary battery, for example, there is a technique such as Japanese Patent Laid-Open Publication No. 2013-246933. In Patent Document 1, 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 is disclosed. Further, 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 using a shrink tube that is a seamless tube.

[0003] Patent Document 1: Japanese Patent Laid-Open Publication No. 2013-246933

[0004] However, in Patent Document 1, after the shrink tube is heat-shrunk, the non-aqueous electrolyte is impregnated. According to the research of the present inventors, in the technique as described above, since the electrode body is covered with the shrink tube, it is difficult to impregnate the electrolyte into the inside of the electrode body. Summary of the Invention

[0005] The technology disclosed herein has been completed in view of the above circumstances, and an object thereof is to provide a method for manufacturing a secondary battery and a secondary battery that have vibration resistance and allow the electrolyte to sufficiently penetrate into the inside of the electrode body.

[0006] The technology disclosed herein relates to a method for manufacturing a secondary battery, which is characterized by including: an assembly body forming step in which an assembly body in which a current collecting terminal and an electrode body are connected is formed; an electrode body housing step in which the electrode body is housed inside a bag-shaped shrink wrap having an upper opening; an electrolyte injection step in which an electrolyte is injected into the inside of the shrink wrap; an electrolyte penetration step in which the electrolyte is allowed to penetrate into the inside of the electrode body; and a shrink wrap heat shrinkage step in which the shrink wrap is heat-shrunk.

[0007] In the above manufacturing method, an electrolytic solution is injected into the inside of a bag-shaped shrink wrap, and the electrolytic solution is permeated into the inside of the electrode body. Thereby, the electrolytic solution can be permeated into the inside of the electrode body. Further, by heat-shrinking the shrink wrap, the current collector terminal and the electrode body are fixed by the shrink wrap. Thereby, it is possible to provide a secondary battery having vibration resistance and allowing the electrolytic solution to sufficiently permeate into the inside of the electrode body. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 FIG. is a perspective view schematically showing a secondary battery according to one embodiment.

[0009] Figure 2 is along Figure 1 II-II line of FIG. is a schematic longitudinal sectional view.

[0010] Figure 3 is along Figure 1 III-III line of FIG. is a schematic longitudinal sectional view.

[0011] Figure 4 FIG. is a flowchart showing a manufacturing method of a secondary battery according to one embodiment.

[0012] Figure 5 FIG. is a schematic view for explaining the state of an electrode body housing step according to one embodiment.

[0013] Figure 6 is a diagram corresponding to Figure 2 of the secondary battery according to the first modification. DETAILED DESCRIPTION

[0014] Hereinafter, several preferred embodiments of the technology disclosed herein will be described with appropriate reference to the drawings. Items required for implementing the present disclosure in items other than those specifically mentioned in this specification (for example, general structures and manufacturing processes of secondary batteries 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 this field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in this field.

[0015] In addition, in the following drawings, components and parts that perform the same function are sometimes given the same reference numerals, and repeated descriptions are omitted or simplified. In this specification, the notation "A to B" indicating a range means A or more and B or less, and includes the meanings of "preferably greater than A" and "preferably less than B". In this specification, the so-called "secondary battery" (hereinafter sometimes simply referred to as "battery") means the entire power storage device that can repeatedly perform charge and discharge by the movement of charge carriers between the positive electrode and the negative electrode via an electrolytic solution.

[0016] Hereinafter, after explaining the structure of the secondary battery 100 disclosed herein, a method for manufacturing the secondary battery disclosed herein will be described. In addition, in the following description, the reference signs L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, upper, and lower. The reference signs 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 and down direction orthogonal to the short side direction and the long side direction of the secondary battery 100, respectively. However, these directions are determined for convenience of explanation and do not limit the installation method of the secondary battery 100 in any way.

[0017] <Secondary Battery>

[0018] Figure 1 is a perspective view schematically showing the secondary battery 100 according to one embodiment. Figure 2 is along Figure 1 schematic longitudinal sectional view taken along line II-II. Figure 3 is along Figure 1 schematic longitudinal sectional view taken along line III-III. As Figure 1 and Figure 2 shown, 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 wrap 80, and an electrolytic solution (not shown). The secondary battery 100 is characterized by including the shrink wrap 80 disclosed herein, and the other structures may be the same as those in the prior art. Hereinafter, the specific structure of the secondary battery 100 will be described.

[0019] The battery case 10 is a housing that houses the electrode body 20, the shrink wrap 80, and the electrolytic solution. As Figure 1 , Figure 2 shown, here, the battery case 10 has an outer shape of a flat and bottomed rectangular parallelepiped (square) shape. As Figure 2 shown, here, the battery case 10 includes an outer package 12 having an opening 12h and a sealing plate (cover) 14 that seals the opening 12h. The battery case 10 is preferably square. The material of the battery case 10 may be the same as the material used in the prior art and is not particularly limited. The battery case 10 is preferably made of metal, for example, more preferably made of aluminum, aluminum alloy, iron, iron alloy, etc.

[0020] As Figure 1 shown, here, the outer package 12 includes a bottom surface 12a, a pair of wide side surfaces 12b extending from the bottom surface 12a and facing each other, and a pair of narrow side surfaces 12c extending from the bottom surface 12a and facing each other. The bottom surface 12a is substantially rectangular. The bottom surface 12a and the opening 12h (see Figure 2)Opposed. The sealing plate 14 is installed on the outer package 12 so as to block the opening 12h of the outer package 12. The sealing plate 14 is opposed to 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 (e.g., welding) the sealing plate 14 to the periphery of the opening 12h of the outer package 12.

[0021] As Figure 1 and Figure 2 shown, here, an exhaust valve 17 is provided on the sealing plate 14. The exhaust valve 17 is a thin-walled portion configured to break when the pressure inside the battery case 10 becomes a specified value or more and discharge the gas inside the battery case 10 to the outside. In addition, in the present embodiment, the exhaust valve 17 is provided on the sealing plate 14, but in other embodiments, the exhaust valve 17 may also be provided on the outer package 12.

[0022] As Figure 1 and Figure 2 shown, here, the positive terminal 30 and the negative terminal 40 are respectively installed on the sealing plate 14. Specifically, the positive terminal 30 is installed at one end of the sealing plate 14 in the longitudinal direction X ( Figure 2 the left end). The negative terminal 40 is installed at the other end of the sealing plate 14 in the longitudinal direction X ( Figure 2 the right end). In addition, in the present embodiment, the positive terminal 30 and the negative terminal 40 are provided on the sealing plate 14, but in other embodiments, the positive terminal 30 and the negative terminal 40 may also be provided on the outer package 12.

[0023] As Figure 2 shown, one end of the positive terminal 30 is exposed on the outer surface of the battery case 10. On the other hand, the other end of the positive terminal 30 is electrically connected to the electrode body 20 via the positive current collecting terminal 34 inside the battery case 10. One end of the negative terminal 40 is exposed on the outer surface of the battery case 10. On the other hand, the other end of the negative terminal 40 is electrically connected to the electrode body 20 via the negative current collecting terminal 44 inside the battery case 10. The positive terminal 30 is preferably formed of a metal having excellent conductivity, such as aluminum or an aluminum alloy. In addition, the negative terminal 40 is preferably formed of a metal having excellent conductivity, such as copper or a copper alloy.

[0024] Here, the positive terminal 30 and the negative terminal 40 are insulated from the battery case 10 (here, the sealing plate 14) respectively through washers (not shown) and insulators (not shown). The washers and insulators can be made of a resin material having electrical insulation properties, such as fluorinated resins such as perfluoroalkoxy fluororesin (PFA), polytetrafluoroethylene (PTFE), polyphenylene sulfide resin (PPS), polypropylene (PP), etc.

[0025] The positive current collector terminal 34 is a component attached to the non-formation portion 52a of the positive current collector 52 where the positive active material layer is not formed, and constitutes a conduction path for electrically connecting the positive electrode 50 and the positive terminal 30. The material of the positive current collector terminal 34 is not particularly limited, and a metal material that can be used for the current collector terminals of existing secondary batteries can be used without particular limitation. The positive current collector terminal 34 is preferably made of the same metal material as the positive current collector 52, such as aluminum, aluminum alloy, nickel, stainless steel, or other conductive metals. The positive current collector terminal 34 is an example of the "current collector terminal" disclosed herein.

[0026] As Figure 2 shown, the positive current collector terminal 34 has a long plate-shaped base portion extending in the vertical direction Z. One end of the positive current collector terminal 34 (the lower end of the positive current collector terminal 34 in Figure 2 this case) is electrically connected to the non-formation portion 52a of the positive current collector 52 where the positive active material layer is not formed. The other end of the positive current collector terminal 34 is electrically connected to the positive terminal 30 inside the battery case 10.

[0027] The negative current collector terminal 44 is a component attached to the non-formation portion 62a of the negative current collector 62 where the negative active material layer is not formed, and constitutes a conduction path for electrically connecting the negative electrode 60 and the negative terminal 40. The material of the negative current collector terminal 44 is not particularly limited, and a metal material that can be used for the current collector terminals of existing secondary batteries can be used without particular limitation. The negative current collector terminal 44 is preferably made of the same metal material as the negative current collector 62, such as copper, copper alloy, nickel, stainless steel, or other conductive metals. The negative current collector terminal 44 is an example of the "current collector terminal" disclosed herein.

[0028] As Figure 2 shown, the negative current collector terminal 44 has a long plate-shaped base portion extending in the vertical direction Z. One end of the negative current collector terminal 44 (the lower end of the negative current collector terminal 44 in Figure 2 this case) is electrically connected to the non-formation portion 62a of the negative current collector 62 where the negative active material layer is not formed. The other end of the negative current collector terminal 44 is electrically connected to the negative terminal 40 inside the battery case 10.

[0029] As Figure 2 shown, here, the positive current collector terminal 34 has a recess 34r that extends from the outer side surface of the positive current collector terminal 34 ( Figure 2 the left side in this case) toward the inside of the recess. The recess 34r is arranged so as to face the later-described shrink wrap 80. On the other hand, the negative current collector terminal 44 has a recess from the outer side surface of the negative current collector terminal 44 ( Figure 2towards the inwardly recessed concave portion 44r on the right side). The concave portion 44r is arranged to face the shrink wrap 80 described later. In several preferred embodiments, the current collecting terminals (the positive current collecting terminal 34 and the negative current collecting terminal 44) preferably have concave portions recessed from the outer side surface of the current collecting terminal towards the inside. The concave portions 34r and 44r are an example of the "concave portion recessed from the outer side surface of the current collecting terminal towards the inside" disclosed herein. The shrink wrap 80 described later is arranged to cover at least a part of the concave portions 34r and 44r respectively. Thereby, the shrink wrap 80 and the positive current collecting terminal 34, and the shrink wrap 80 and the negative current collecting terminal 44 are properly fixed. In other words, it is possible to appropriately prevent the shrink wrap 80 from shifting during the use of the secondary battery 100. However, the concave portions 34r and 44r are not essential. In other embodiments, the positive current collecting terminal 34 and the negative current collecting terminal 44 may not have concave portions. Additionally, it may be that either the positive current collecting terminal 34 or the negative current collecting terminal 44 has the concave portions 34r and 44r.

[0030] As Figure 2 shown, in the present embodiment, the shapes of the concave portions 34r and 44r are square. However, the shapes of the concave portions 34r and 44r are not limited thereto. For example, the shapes of the concave portions 34r and 44r can be V-shaped, U-shaped, semi-circular, etc.

[0031] The maximum depth of the concave portions 34r and 44r (here, when observed in the X direction, the maximum value of the depth from the outer side surface of the positive current collecting terminal 34 to the concave portion 34r. Or, the maximum value of the depth from the outer side surface of the negative current collecting terminal 44 to the concave portion 44r) is, for example, 1 mm or more, preferably 1.5 mm or more, and more preferably 2 mm or more. Thereby, the shrink wrap 80 can be properly fixed to the positive current collecting terminal 34 and the negative current collecting terminal 44. On the other hand, from the viewpoint of ensuring the strength of the positive current collecting terminal 34 and the negative current collecting terminal 44, the maximum depth h1 of the concave portions 34r and 44r is, for example, 1 / 2 or less of the width of the positive current collecting terminal 34 and the negative current collecting terminal 44, preferably 1 / 3 or less, and more preferably 1 / 4 or less.

[0032] As Figure 2 shown, in the present embodiment, one concave portion 34r is formed on the outer side surface of the positive current collecting terminal 34, and one concave portion 44r is formed on the outer side surface of the negative current collecting terminal 44. However, the present disclosure is not limited thereto. A plurality of concave portions 34r and 44r may be formed on the outer side surfaces of the positive current collecting terminal 34 and the negative current collecting terminal 44. Additionally, the concave portions 34r and 44r are preferably arranged at a position on the outer side surfaces of the positive current collecting terminal 34 and the negative current collecting terminal 44 where at least a part of the shrink wrap 80 after heat shrinkage is covered by the concave portions 34r and 44r.

[0033] The electrode body 20 is a power generation element of the secondary battery 100. As Figure 2 shown, the electrode body 20 has openings 20h at both ends in the width direction ( Figure 2 Y direction). 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 wrap 80 described later. As Figure 3 shown, in the present embodiment, one electrode body is housed inside the battery case 10. However, the number of electrode bodies 20 housed inside one battery case 10 is not particularly limited, and multiple (two or more) electrode bodies 20 may be housed in a state where each is coated with a shrink wrap 80.

[0034] Here, the electrode body 20 is a flat wound electrode body formed by overlapping a strip-shaped positive electrode 50 and a strip-shaped negative electrode 60 via two strip-shaped separators 70 and winding them in the long side direction. However, the electrode body may also be a stacked electrode body in which a rectangular positive electrode and a rectangular negative electrode are alternately stacked via a rectangular separator. In addition, the electrode body may also be a zigzag stacked electrode body formed by sandwiching a plurality of positive electrodes and a plurality of negative electrodes between separators folded into a zigzag shape. In several preferred embodiments, the electrode body 20 is preferably a wound electrode body.

[0035] The positive electrode 50 has a strip-shaped positive electrode current collector 52 and a positive electrode active material layer 54 fixedly attached to at least one surface of the positive electrode current collector 52. As Figure 2 shown, here, the positive electrode 50 has a structure in which the positive electrode active material layer 54 is formed along the long side direction on one or both sides (here, both sides) of the long strip-shaped positive electrode current collector 52. Here, the non-formed part 52a of the positive electrode active material layer (that is, the part where the positive electrode current collector 52 is exposed without the positive electrode active material layer 54 being formed) is formed 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 above-mentioned long side direction).

[0036] For each component constituting the positive electrode 50, existing well-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 a lithium-nickel-cobalt-manganese composite oxide) that can reversibly absorb and release charge carriers. In addition, the positive electrode active material layer 54 may also contain any components other than the positive electrode active material, such as a conductive material, an adhesive, and various additive components. As the conductive material, for example, a carbon material such as acetylene black (AB) can be used. As the adhesive, for example, polyvinylidene fluoride (PVDF) can be used.

[0037] The negative electrode 60 has a strip-shaped negative electrode current collector 62 and a negative electrode active material layer 64 fixedly attached to at least one surface of the negative electrode current collector 62. As Figure 2 shown, here, the negative electrode 60 has a structure in which the negative electrode active material layer 64 is formed along the long side direction on one or both sides (here, both sides) of the long strip-shaped negative electrode current collector 62. Here, the non-formed portion 62a of the negative electrode active material layer (that is, the portion where the negative electrode current collector 62 is exposed without the negative electrode active material layer 64 formed) is formed 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 above long side direction).

[0038] For each component constituting the negative electrode 60, existing well-known materials that can be used in a general battery (such as a lithium-ion secondary battery) can be used without particular limitation. For example, the negative electrode current collector 62 is preferably made of a conductive metal such as copper, copper alloy, nickel, stainless steel, etc. The negative electrode active material layer 64 contains a negative electrode active material (such as a carbon material like graphite) that can reversibly absorb and release charge carriers. In addition, the negative electrode active material layer 64 may also contain any components other than the negative electrode active material, such as a conductive material, a binder, a dispersant, a thickener, various additive components, etc. As the binder, for example, rubber-like materials such as styrene-butadiene rubber (SBR) can be used. As the dispersant, for example, cellulose-like materials such as carboxymethyl cellulose (CMC) can be used.

[0039] The separator 70 is a component that insulates the positive electrode active material layer from 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 preferably used. 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, titanium dioxide, etc. can be used.

[0040] The electrolyte and the electrode body 20 are housed together inside the shrink wrap 80. Typically, the electrolyte penetrates into the inside of the electrode body 20 (between the positive electrode 50 and the negative electrode 60). However, it is not necessary for all of the electrolyte to penetrate into the inside of the electrode body 20, and a part of the electrolyte may exist outside the electrode body 20 as the remaining electrolyte. In this case, typically, the remaining electrolyte exists between the shrink wrap 80 and the outer surface of the electrode body 20. The electrolyte may be the same as that of a normal secondary battery and is not particularly limited. Typically, the electrolyte is a non-aqueous liquid electrolyte (non-aqueous electrolyte) 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). As the non-aqueous solvent, it is preferable to mix EC, EMC, and DMC in the range of 1 to 99% respectively so that the total ratio becomes 100%. As the supporting salt, for example, a fluorinated lithium salt or the like can be used. The fluorinated lithium salt preferably includes lithium hexafluorophosphate (LiPF 6 ), lithium bis(fluorosulfonyl)imide (LiFSI) known as F 2 LiNO 4 S 2 ), 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.

[0041] The shrink wrap 80 and the electrode body 20 are housed together inside the battery case 10. The shrink wrap 80 is disposed between the battery case 10 and the electrode body 20. As Figure 3 shown, here, the shrink wrap 80 is a bottomed member that can house the electrode body 20. As Figure 3 shown, the shrink wrap 80 thermally shrinks itself to cover the outer surface of the electrode body 20. The shrink wrap 80 is disposed so as to cover the openings 20h ( Figure 2 the left end and the right end) at both ends of the electrode body 20. Also, the shrink wrap 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 and the positive current collector terminal 34 and the negative current collector terminal 44 are respectively fixed. As Figure 2 and Figure 3 shown, here, the shrink wrap 80 has an opening 80h at the upper end. The opening 80h of the shrink wrap 80 may be left as it is or may be in a state of being sealed by heat sealing or the like. As Figure 3As shown, here, the opening 80h of the shrink wrap 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 wrap 80. Thereby, the electrolyte inside the electrode body 20 can be appropriately maintained. However, it is not necessary to completely seal the opening 80h of the shrink wrap 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 wrap 80, it is preferable that at least a part of the opening 80h is not sealed. For example, the portions of the positive current collector terminal 34 and the negative current collector terminal 44 covered by the shrink wrap 80 in the opening 80h may not be sealed.

[0042] As the shrink wrap 80, for example, a heat-shrinkable resin such as polyethylene (PE), polypropylene (PP), polyolefin, polyvinyl chloride (PVC), polyethylene terephthalate (PET), or fluororesin can be used. Among them, PET can also be suitably used as the shrink wrap 80.

[0043] The secondary battery 100 disclosed herein can maintain the electrolyte inside the electrode body 20 by including a shrink wrap 80 that covers the outer surface of 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 this expansion and contraction, the electrolyte present inside the electrode body 20 may be pressed out from the opening 20h of the electrode body 20 to the outside of the electrode body 20, resulting in an insufficient amount of electrolyte being unable to be maintained 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 wrap 80. Therefore, even when the electrode body 20 expands and contracts, the outflow of the electrolyte inside the electrode body 20 to the outside can be prevented.

[0044] In addition, the secondary battery 100 disclosed herein fixes the electrode body 20 to the positive current collector terminal 34 and the negative current collector terminal 44 respectively by the shrink wrap 80. Thereby, for example, even when vibrations or impacts (external forces) are applied during the use of the secondary battery 100, the movement of the electrode body 20 inside the battery case 10 can be suppressed, thereby suppressing damage to the electrode body 20. In addition, when the secondary battery 100 has recesses 34r and 44r, the shrink wrap 80 and the positive current collector terminal 34 and the negative current collector terminal 44 are fixed more reliably. During the use of the secondary battery 100, the deviation of the shrink wrap 80 can be further suppressed.

[0045] The secondary battery 100 can be used for various applications. As preferred applications, there can be mentioned power sources for driving vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). In addition, the secondary battery 100 can be used as a storage battery such as a small power storage device. Typically, the secondary battery 100 can also be used in the form of a battery pack formed by connecting a plurality of them in series and / or in parallel.

[0046] In addition, as an example, a square secondary battery 100 having an electrode body 20 with a flat wound structure has been described. However, the secondary battery disclosed herein is not limited to this shape. For example, alternatively, the secondary battery according to the present embodiment can also be configured in the form of a cylindrical secondary battery, a coin-type secondary battery, or the like.

[0047] <Manufacturing method of secondary battery>

[0048] Next, the manufacturing method of the secondary battery 100 disclosed herein will be described. Figure 4 It is a flowchart showing the manufacturing method of the secondary battery 100 according to one embodiment. The manufacturing method disclosed herein includes an assembly body forming step S10, an electrode body housing step S20, an electrolyte injection step S30, an electrolyte penetration step S40, and a shrink wrap heat shrinkage step S50. In addition, the manufacturing method disclosed herein is characterized by the electrolyte injection step and the shrink wrap heat shrinkage step, and the other manufacturing steps can be the same as those in the past. In addition, other steps can be further included at any stage. In addition, the materials used in the manufacturing of the secondary battery 100 can be the same as the materials described above, so the repeated description is omitted here.

[0049] (Assembly body forming step S10)

[0050] In the assembly body forming step S10, an assembly body connected with a current collector terminal and an electrode body is formed. In addition, in this specification, the so-called "assembly body" means a structure having a current collector terminal and an electrode body. The assembly body formed by this embodiment includes a positive current collector terminal 34, a negative current collector terminal 44, and an electrode body 20.

[0051] In the assembly body forming step S10, as Figure 2As shown, the exposed portion of the positive current collector of the electrode body 20 (the non-forming portion 52a of the positive active material layer) is joined to the positive current collector terminal 34. On the other hand, the exposed portion of the negative current collector of the electrode body 20 (the non-forming portion 62a of the negative active material layer) is joined to the negative current collector terminal 44. This joining can be performed, for example, by existing well-known methods (such as ultrasonic joining, resistance welding, laser welding, etc.). Thus, the electrode body 20, the positive current collector terminal 34, and the negative current collector terminal 44 are integrated.

[0052] Although not limited thereto, in the present embodiment, after the assembly manufacturing process S10, the assembly manufactured in the above process can be further integrated with the sealing plate 14. Specifically, first, a sealing plate 14 (refer to Figure 5 ) having the positive terminal 30 and the negative terminal 40 mounted thereon is prepared. Then, the positive terminal 30 and the positive current collector terminal 34, and the negative terminal 40 and the negative current collector terminal 44 are joined by existing well-known methods (such as ultrasonic joining, resistance welding, laser welding, etc.). Thus, the positive terminal 30 is electrically connected to the electrode body 20 via the positive current collector terminal 34. In addition, the negative terminal 40 is electrically connected to the electrode body 20 via the negative current collector terminal 44. In addition, thus, the assembly and the sealing plate 14 are integrated. However, the connection between the positive terminal 30 and the positive current collector terminal 34, and the connection between the negative terminal 40 and the negative current collector terminal 44 do not need to be performed immediately after the assembly manufacturing process S10, and can be performed at any time as long as it is before the sealing plate 14 is encapsulated in the outer package 12.

[0053] (Electrode body housing process S20)

[0054] In the electrode body housing process S20, the electrode body 20 is housed inside a bag-shaped shrink wrap 80 having an opening 80h at the upper part. The electrode body 20 becomes a state of an assembly joined to the positive current collector terminal 34 and the negative current collector terminal 44 via the assembly manufacturing process.

[0055] Figure 5 is a schematic diagram for explaining the appearance of the electrode body housing process S20 according to one embodiment. As Figure 5 shown, in the present embodiment, the positive current collector terminal 34 and the negative current collector terminal 44 are integrated with the sealing plate 14 via the positive terminal 30 and the negative terminal 40.

[0056] Typically, the shrink wrap 80 prepared in the electrode body housing process S20 (that is, the shrink wrap 80 before the shrink wrap heat shrinkage process) is a bag-shaped member having an opening 80h at the upper part. In addition, in this specification, the so-called "bag-shaped" means a bottomed shape that can house the electrolyte. For example, it is a concept that includes not only a bottomed cylindrical shape but also a shape having a side wall portion at the bottom, a box shape, etc. AsFigure 5 As shown, here, the shrink wrap 80 has a bottomed cylindrical shape.

[0057] In the electrode body housing step S20, the electrode body 20 is housed through the opening 80h of the shrink wrap 80. As Figure 5 shown, 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 wrap 80. Here, the electrode body 20 is arranged such that the width direction of the opening 80h of the shrink wrap 80 is substantially parallel to the winding axis of the electrode body 20. A part of the positive current collecting terminal 34 and the negative current collecting terminal 44, including the connecting portion connected to the electrode body 20, is housed together with the electrode body 20 in the shrink wrap 80. On the other hand, a part of the positive current collecting terminal 34 and the negative current collecting terminal 44 is arranged so as to protrude upward from the opening 80h of the shrink wrap 80. When the positive current collecting terminal 34 and the negative current collecting terminal 44 have recesses 34r, 44r, it is preferable to house the positive current collecting terminal 34 and the negative current collecting terminal 44 such that the opening 80h of the shrink wrap 80 is located above the upper end portions of the recesses 34r, 44r (in other words, covers the recesses 34r, 44r). Thereby, in the subsequent shrink wrap heat shrinkage step, it is easy to cover the shrink wrap 80 in the recesses 34r, 44r.

[0058] The size and shape of the shrink wrap 80 prepared in the electrode body housing step S20 can be appropriately adjusted according to the size of the electrode body 20, the shape of the battery case 10, etc., and thus are not particularly limited. The shrink wrap 80 before heat shrinkage preferably has a margin (gap) in size when housing the electrode body 20. Thereby, the electrode body 20 can be easily housed in the shrink wrap 80. In addition, in the electrolyte impregnation step S40 described later, the electrolyte can easily penetrate into the interior of the electrode body 20.

[0059] The thickness of the shrink wrap 80 before heat shrinkage can be adjusted, for example, by the size of the electrode body 20, the amount of electrolyte injection, and the resin constituting the shrink wrap 80. From the viewpoint of making the strength of the shrink wrap 80 after heat shrinkage sufficient, the thickness of the shrink wrap 80 before heat shrinkage is preferably 30 μm or more, more preferably 50 μm or more. On the other hand, from the viewpoints of the production efficiency of the secondary battery 100, etc., the thickness of the shrink wrap 80 before heat shrinkage is preferably 200 μm or less, more preferably 150 μm or less.

[0060] (Electrolyte injection step S30)

[0061] In the electrolyte injection process S30, electrolyte is injected into the interior of the shrink wrap 80 through the opening 80h of the shrink wrap 80. Thus, compared with the case of directly injecting into the battery case 10, even with a smaller injection volume of electrolyte, the electrolyte can penetrate into the interior of the electrode body 20 through the subsequent electrolyte penetration process S40. The electrolyte injection process S30 can also be carried out at atmospheric pressure. For example, it can also be carried out in a decompression environment such as in a chamber capable of adjusting pressure.

[0062] The electrolyte injection process S30 is preferably carried out after the electrode body accommodation process S20 (i.e., in a state where the electrode body 20 is accommodated in the shrink wrap 80 before heat shrinkage). However, it is not limited thereto, and the electrolyte injection process S30 can also be carried out at a timing before the electrode body accommodation process S20 (i.e., in a state where the electrode body 20 is not accommodated in the shrink wrap 80 before heat shrinkage).

[0063] (Electrolyte Penetration Process S40)

[0064] In the electrolyte penetration process S40, the electrolyte is made to penetrate into the electrode body 20 accommodated inside the shrink wrap 80. Here, the shrink wrap 80 is in a state before heat shrinkage. That is, it is in a state before the opening 20h of the electrode body 20 is covered by the shrink wrap 80. Therefore, the electrolyte easily penetrates from the opening 20h of the electrode body 20.

[0065] In the electrolyte penetration process S40, it is preferable to accommodate the electrode body 20 accommodated inside the shrink wrap 80 in a chamber capable of adjusting pressure and carry out the process under reduced pressure conditions. Thus, since the interior of the electrode body 20 (between the positive electrode 50 and the negative electrode 60) becomes negative pressure, the electrolyte is attracted to the interior of the electrode body 20 that has become negative pressure. Therefore, the electrolyte can be efficiently penetrated into the interior of the electrode body 20. In addition, the time required for the electrolyte penetration process S40 can be shortened.

[0066] When carrying out the electrolyte penetration process S40 under reduced pressure conditions, the internal pressure in the chamber is preferably -50 kPa or less, more preferably -80 kPa or less. Thus, the time required for the electrolyte penetration process S40 can be shortened. On the other hand, when decompressing the interior of the decompression chamber, unless the decompression chamber is damaged, the lower limit value of the pressure during the decompression process is not particularly limited. For example, the lower limit value of the pressure in the decompression chamber can also be -100 kPa or more.

[0067] In addition, the decompression treatment in the electrolyte penetration process S40 is not necessary, or the decompression treatment does not need to be continued. For example, in the electrolyte penetration process S40, in addition to the decompression treatment, a pressurization treatment can also be repeatedly carried out. Thus, the penetration of the electrolyte into the interior of the electrode body 20 can be promoted.

[0068] When performing the pressing process in the electrolyte impregnation process S40, the internal pressure in the chamber is preferably, for example, 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 pressing process can be, for example, 1.0 MPa or less.

[0069] In addition, after the electrolyte impregnation process S40, the opening 80h of the shrink wrap 80 can also be sealed by heat sealing or the like. Thereby, the electrolyte is easily retained inside the shrink wrap 80. In addition, the shift of the shrink wrap 80 can be more suitably suppressed. In addition, without completely sealing the opening 80h of the shrink wrap 80, only a part of the opening 80h can be sealed. In addition, the sealing can also be performed discontinuously. However, the sealing of the shrink wrap 80 is not essential and can be omitted.

[0070] (Shrink wrap heat shrinkage process S50)

[0071] In the shrink wrap heat shrinkage process S50, the shrink wrap 80 is heat shrunk. Thereby, the shrink wrap 80 shrinks and is arranged so as to cover the outer surface of the electrode body 20. In addition, through this process, the openings 20h at both ends of the electrode body 20 are in a state covered by the shrink wrap 80. In addition, the electrode body 20, the positive current collector terminal 34, and the negative current collector terminal 44 are fixed by the shrink wrap 80. Thereby, the vibration resistance and shock resistance of the secondary battery 100 can be obtained.

[0072] The method of heat shrinking the shrink wrap 80 is not particularly limited, and an existing well-known method can be adopted. For example, the shrink wrap 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 performed by heating in the shrink furnace at a temperature equal to or higher than the shrink temperature of the shrink wrap 80.

[0073] In the case where the positive current collector terminal 34 and the negative current collector terminal 44 have recesses, for example, as Figure 2 shown, it is preferable to heat shrink the shrink wrap 80 in such a manner that at least a part of the heat-shrunk shrink wrap 80 covers the recesses 34r, 44r respectively. In other words, it is preferable to heat shrink the shrink wrap 80 in such a manner that at least a part of the shrink wrap 80 is hooked on the recesses 34r, 44r. Thereby, the shrink wrap 80 and the positive current collector terminal 34 and the negative current collector terminal 44 are more firmly fixed. Therefore, the shift of the shrink wrap 80 can be further suppressed during the use of the manufactured secondary battery 100.

[0074] After the heat shrinkage process S50 of the shrink wrap, the secondary battery 100 can be manufactured by housing the assembly inside the outer package 12 and 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 outer package 12. Then, the sealing plate 14 and the periphery of the opening 12h of the outer package 12 are joined by laser welding or the like. Thus, the battery case 10 is sealed. In addition, 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 the assembly and the method of sealing the sealing plate 14 may be implemented by existing well-known means, and the manufacturing method of the secondary battery disclosed herein is not a feature.

[0075] As described above, the preferred embodiments of the present disclosure have been described, but the above embodiments are just examples. In addition, the present disclosure can be implemented in various ways. The present disclosure can be implemented based on the content disclosed in this specification and the common general knowledge in this field. For the technologies described in the technical solutions, it includes the technologies obtained by making various deformations and changes to the embodiments illustrated above. For example, a part of the above embodiments can be replaced with other deformation examples, or other deformation examples can be added to the above embodiments. In addition, if the technical feature is not described as essential, it can also be appropriately deleted.

[0076] <First Modification Example>

[0077] Figure 6 is a diagram corresponding to the Figure 2 secondary battery 200 according to the first modification example. In the secondary battery 200 according to the first modification example, a positive current collector terminal 134 is provided instead of the positive current collector terminal 34. In addition, in the secondary battery 200 according to the first modification example, a negative current collector terminal 144 is provided instead of the negative current collector terminal 44. Except for the above points, the secondary battery 200 may have the same structure as the above secondary battery 100.

[0078] As Figure 6 shown, instead of the concave portions 34r and 44r, the positive current collector terminal 134 and the negative current collector terminal 144 each have a convex portion 134p and 144p, respectively. The convex portion 134p is formed so as to protrude outward from the outer side surface ( Figure 6 the left side) of the positive current collector terminal 134. On the other hand, the convex portion 144p is formed so as to protrude outward from the outer side surface ( Figure 6is formed to protrude outward (on the right side in the figure). The convex portions 134p and 144p are arranged to face the shrink wrap 80 described later respectively. Here, they are arranged such that at least a part of the convex portions 134p and 144p is covered by the shrink wrap 80 after heat shrinkage. Thereby, the shrink wrap 80 and the positive current collector terminal 134, and the shrink wrap 80 and the negative current collector terminal 144 are fixed more reliably. In other words, during the use of the secondary battery 200, the shift of the shrink wrap 80 can be further suppressed. As Figure 6 shown here, the positive current collector terminal 134 and the negative current collector terminal 144 each have convex portions 134p and 144p respectively. However, it can also be that either the positive current collector terminal 134 or the negative current collector terminal 144 has the convex portions 134p and 144p. The convex portions 134p and 144p are an example of the "convex portions protruding outward from the outer side surface of the current collector terminal" disclosed herein.

[0079] As Figure 6 shown, the shapes of the convex portions 134p and 144p according to the first modification example are square. 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 can be V-shaped, U-shaped, semi-circular, etc.

[0080] The maximum height of the convex portions 134p and 144p (here, when observed in the X direction, the maximum value of the height from the outer side surface of the positive current collector terminal 134 to the convex portion 134p. Or, the maximum value of the height from the outer side surface of the negative current collector 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 wrap 80 can be appropriately fixed to the positive current collector terminal 134 and the negative current collector 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.

[0081] As Figure 6 shown, one convex portion 134p is formed on the outer side surface of the positive current collector terminal 134, and one convex portion 144p is formed on the outer side surface of the negative current collector terminal 144 according to the first modification example. However, the present disclosure is not limited thereto. A plurality of convex portions 134p and 144p can also be formed on the outer side surfaces of the positive current collector terminal 134 and the negative current collector terminal 144. In addition, in addition to the convex portions 134p and 144p, concave portions such as the concave portions 34r and 44r described above can also be formed on the outer side surfaces of the positive current collector terminal 134 and the negative current collector terminal 144.

[0082] The secondary battery 200 according to the first modification example can be manufactured by the same method as the secondary battery 100 described above.

[0083] In the method for manufacturing the secondary battery 200 according to the first modification example, in the electrode body housing step S20, it is preferable to house the positive current collector terminal 134 and the negative current collector terminal 144 in such a manner that the opening 80h of the shrink wrap 80 is located above the upper end portions of the convex portions 134p and 144p (in other words, in such a manner as to cover the convex portions 134p and 144p). Thereby, in the shrink wrap heat shrinkage step S50, the convex portions 134p and 144p are easily covered by the shrink wrap.

[0084] In the method for manufacturing the secondary battery 200 according to the first modification example, in the shrink wrap heat shrinkage step S50, it is preferable to heat shrink the shrink wrap 80 in such a manner that at least a part of the heat-shrunk shrink wrap 80 covers the convex portions 134p and 144p respectively. In other words, it is preferable to heat shrink the shrink wrap 80 in such a manner that at least a part of the shrink wrap 80 is hooked on the convex portions 134p and 144p. Thereby, the shrink wrap 80 and the positive current collector terminal 134 and the negative current collector terminal 144 are fixed more firmly. Therefore, during the use of the manufactured secondary battery 200, the shift of the shrink wrap 80 can be further suppressed.

[0085] As described above, as specific embodiments of the technology disclosed herein, the embodiments described in the following items can be cited.

[0086] Item 1: A method for manufacturing a secondary battery, comprising: an assembly body forming step of forming an assembly body 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 wrap having an upper opening; an electrolytic solution injection step of injecting an electrolytic solution into the inside of the shrink wrap; an electrolytic solution penetration step of causing the electrolytic solution to penetrate into the inside of the electrode body; and a shrink wrap heat shrinkage step of heat shrinking the shrink wrap.

[0087] Item 2: In the method for manufacturing a secondary battery according to Item 1,

[0088] The electrode body is housed in a chamber capable of adjusting pressure, and the electrolytic solution penetration step is performed under reduced pressure conditions.

[0089] Item 3: In the method for manufacturing a secondary battery according to Item 1 or Item 2, the current collector terminal has a recess facing inward from the outer side surface of the current collector terminal, and in the shrink wrap heat shrinkage step, the shrink wrap is heat shrunk in such a manner as to cover the recess.

[0090] Item 4: In the method for manufacturing a secondary battery according to any one of Items 1 to 3, the current collector terminal has a convex portion facing outward from the outer side surface of the current collector terminal, and in the shrink wrap heat shrinkage step, the shrink wrap is heat shrunk in such a manner as to cover the convex portion.

[0091] Item 5: A secondary battery, comprising: an electrode body having openings at both end portions in the width direction; an electrolytic solution that penetrates into the electrode body; a battery case that houses the electrode body; a terminal that is attached to the battery case; a current collecting terminal that connects the electrode body and the terminal; and a shrink wrap that covers an outer surface of the electrode body, wherein the shrink wrap is disposed so as to cover the openings of the electrode body.

[0092] Item 6: In the secondary battery according to Item 5, the current collecting terminal has a recess that faces inward from an outer side surface of the current collecting terminal, and the shrink wrap is disposed so as to cover the recess.

[0093] Item 7: In the secondary battery according to Item 5 or Item 6, the current collecting terminal has a protrusion that faces outward from an outer side surface of the current collecting terminal, and the shrink wrap is disposed so as to cover the protrusion.

[0094] Item 8: In the secondary battery according to any one of Items 5 to 7, the electrode body is a wound electrode body in which a positive electrode and a negative electrode are wound with a separator therebetween.

Claims

1. A method for manufacturing a secondary battery, characterized in that: have: An assembly forming step of forming an assembly by connecting a collector terminal and an electrode body; an electrode body housing step of housing the electrode body in a bag-shaped shrink package having an upper opening; an electrolyte injection step of injecting electrolyte into the interior of the shrink package; An electrolyte infiltration step of allowing the electrolyte to infiltrate the interior of the electrode body; as well as The shrink pack heat shrinking step heat shrinks the shrink pack.

2. The method for manufacturing a secondary battery according to claim 1, characterized in that: The electrode body is housed in a chamber capable of adjusting pressure, and the electrolyte solution impregnation step is performed under reduced pressure.

3. The method for manufacturing a secondary battery according to claim 1 or 2, characterized in that: The collector terminal has a recessed portion extending from the outer side surface of the collector terminal toward the inner side. In the shrink pack heat shrinking step, the shrink pack is heat shrunk so that the shrink pack covers the recessed portion.

4. The method for manufacturing a secondary battery according to claim 1 or 2, characterized in that: The collector terminal has a convex portion extending outward from an outer side surface of the collector terminal. In the shrink pack heat shrinking step, the shrink pack is heat shrunk so that the shrink pack covers the convex portion.

5. A secondary battery, characterized in that: have: an electrode body having openings at both ends in the width direction; an electrolyte solution that permeates into the interior of the electrode body; A battery housing, the battery housing accommodating the electrode body; A terminal mounted on the battery housing; A collector terminal connecting the electrode body and the terminal; as well as a shrink wrap covering an outer surface of the electrode body, The shrink pack is arranged to cover the opening of the electrode body.

6. The secondary battery according to claim 5, characterized in that: The collector terminal has a recessed portion extending inward from an outer side surface of the collector terminal, and the shrink wrap is arranged to cover the recessed portion.

7. The secondary battery according to claim 5, characterized in that: The current collector terminal has a protrusion extending outward from an outer side surface of the current collector terminal, and the shrink wrap is arranged to cover the protrusion.

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

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