JP5134781B2 - Battery manufacturing method - Google Patents

Description

  The present invention relates to a battery manufacturing method suitable for manufacturing a nonaqueous electrolyte battery.

  In a battery suitable for high output, such as a lithium ion secondary battery, a technique for enlarging the electrode surface area by spirally forming a belt-like positive electrode, a separator, and a negative electrode is generally performed. Also, copper is generally used for the negative electrode current collector on which the negative electrode active material is formed from the viewpoint of physical processing strength. In recent years, a cylindrical lithium ion secondary battery including an electrode body wound in a spiral shape has been developed for an electric vehicle.

  As a method for collecting current from an electrode body in a cylindrical lithium ion secondary battery, for example, Patent Document 1 discloses at least one of a positive electrode current collector made of an aluminum foil and a negative electrode current collector made of a copper foil. An arc-shaped current extraction portion is formed so as to protrude from the end of the separator, and the current extraction portion is provided for each turn so as to be arranged in parallel in the radial direction of the spiral electrode body. A technique for forming a terminal by overlapping and welding the portions has been proposed.

  However, in the secondary battery described in Patent Document 1, since the copper foil is used for the negative electrode current collector, when the potential of the negative electrode increases due to overdischarge, the negative electrode current collector dissolves and the discharge capacity rapidly increases. There was a problem of lowering.

  Therefore, in order to improve the overdischarge characteristics of the nonaqueous electrolyte battery, as proposed in Patent Document 2, aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less is used for the negative electrode current collector. ing.

  A laminated electrode group using this negative electrode current collector is manufactured by the method described below. First, a negative electrode active material-containing layer is formed by removing one end of the negative electrode current collector, and then a negative electrode tab is formed by punching at one end of the negative electrode current collector to obtain a negative electrode. Moreover, after forming a positive electrode active material containing layer by excluding one end portion of the positive electrode current collector, a positive electrode tab is formed on one end portion of the positive electrode current collector by punching to obtain a positive electrode. The obtained positive electrode and negative electrode are alternately laminated with a separator interposed therebetween, thereby obtaining an electrode group.

However, the above-described negative electrode current collector cannot obtain sufficient strength when the thickness is reduced to increase the capacity. Therefore, the negative electrode tab is easily bent or broken during punching, and mass productivity is reduced. This causes the problem.
Japanese Patent Application Laid-Open No. 11-73995 JP-A-2005-123183

  An object of the present invention is to improve the mass productivity of a battery manufacturing method using a current collector made of aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less.

The battery manufacturing method according to the present invention includes a positive electrode current collector formed of aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less and a thickness of 20 μm or less, and a positive electrode current collector formed at one end of the current lead-out portion. A plurality of positive electrodes including a positive electrode active material-containing layer formed excluding at least the current deriving portion, a current deriving portion formed at one end, and a thickness of 20 μm made of aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less The following negative electrode current collector and a plurality of negative electrodes including a negative electrode active material-containing layer formed excluding at least the current deriving portion of the negative electrode current collector, the positive electrode active material-containing layer and the negative electrode active material-containing layer Are laminated so that at least one member of the separator and the electrolyte layer is interposed therebetween, and the current lead-out portion of the positive electrode is connected to the negative electrode on one side of the laminate. And a step of also protrudes from the positive electrode and the member of the current lead portion of the negative electrode at the opposite side edges of the even protrude from the member and the laminate,
Integrating the current deriving portion of the positive electrode by welding to form a positive electrode terminal, and integrating the current deriving portion of the negative electrode by welding to form a negative electrode terminal;
Cutting each of the positive terminal and the negative terminal into strips;
And storing the obtained electrode group in a container so that the positive electrode terminal and the negative electrode terminal are drawn out of the container.

In addition, the battery manufacturing method according to the present invention includes a positive electrode current collector having a thickness of 20 μm or less and a positive electrode current collector formed of aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less, with a current lead-out portion formed at one end. A plurality of positive electrodes including a positive electrode active material-containing layer formed excluding at least the current deriving portion of the body, and a thickness made of aluminum or an aluminum alloy having a current deriving portion formed at one end and an average crystal grain size of 50 μm or less A negative electrode current collector having a thickness of 20 μm or less and a plurality of negative electrodes including a negative electrode active material-containing layer formed excluding at least the current deriving portion of the negative electrode current collector, the positive electrode active material-containing layer and the negative electrode active material Laminating so that at least one member of the separator and the electrolyte layer is interposed between the containing layers, Serial and negative electrode and also protrudes from the member, and step also protrudes from the positive electrode and the member of the current lead portion of the negative electrode at the opposite side edges of the laminate,
A step of cutting the respective said current deriving unit of the current deriving unit and the negative electrode obtained by the projection of the is protruded the positive electrode strip,
After the cutting, forming the positive electrode terminal by integrating the current deriving portion of the positive electrode by welding, and integrating the current deriving portion of the negative electrode by welding to form a negative electrode terminal;
And storing the obtained electrode group in a container so that the positive electrode terminal and the negative electrode terminal are drawn out of the container.

  According to the present invention, the mass productivity of a battery manufacturing method using a current collector made of aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less can be improved.

(First embodiment)
A method for manufacturing a battery according to the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram illustrating a manufacturing process of a positive electrode, a separator, and a negative electrode, FIG. 2 is a schematic diagram illustrating a process of stacking the positive electrode, the separator, and the negative electrode, and FIG. 3 is a method according to the first embodiment. It is a perspective view which shows the manufactured laminated electrode group.

  As shown in FIG. 1, a positive electrode active material-containing layer 2 is formed on both surfaces of a strip-shaped positive electrode current collector made of aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less, except for the current deriving portion 1 on the long side. . Next, a plurality of strip-shaped positive electrodes 3 are obtained by cutting so as to be orthogonal to the long side direction. Further, the negative electrode active material-containing layer 5 is formed on both surfaces of a strip-shaped negative electrode current collector made of aluminum or an aluminum alloy having an average crystal particle diameter of 50 μm or less, except for the current deriving portions 4 on the long side. Next, a plurality of strip-shaped negative electrodes 6 are obtained by cutting so as to be orthogonal to the long side direction. Further, a plurality of bag-like separators 8 are obtained from the porous sheet 7. The bag-shaped separator 8 is obtained by folding back the porous sheet 7 cut into a desired dimension along the long side and heat-sealing the overlapping long side portion and one short side portion. The boundary of the heat fusion region is indicated by a dotted line 8a in FIG. As the porous sheet 7, a synthetic resin nonwoven fabric, a polyethylene porous film, a polypropylene porous film, or the like can be used.

  By forming the positive electrode current collector and the negative electrode current collector from aluminum having an average crystal particle diameter of 50 μm or less or an aluminum alloy having an average crystal particle diameter of 50 μm or less, the overdischarge characteristics of the nonaqueous electrolyte battery can be improved. . A more preferable average crystal particle size is 3 μm or less. Moreover, it is desirable that the lower limit value of the average crystal particle diameter is 0.01 μm.

The average crystal particle diameter of aluminum and aluminum alloy is measured by the method described below. The structure of the current collector surface is observed with a metal microscope, the number n of crystal grains existing in a 1 mm × 1 mm visual field is measured, and the average crystal grain area S (μm ² ) is calculated from the following formula (A).

S = (1 × 10 ⁶ ) / n (A)
Here, the value represented by (1 × 10 ⁶ ) is a visual field area (μm ² ) of 1 mm × 1 mm, and n is the number of crystal grains.

  The average crystal particle diameter d (μm) is calculated from the following formula (B) using the obtained average crystal particle area S. Such calculation of the average crystal particle diameter d was performed for five locations (five fields of view), and the average value was defined as the average crystal particle diameter. Note that the assumed error is about 5%.

d = 2 (S / π) ^1/2 (B)
The thickness of the negative electrode current collector is preferably 20 μm or less in order to increase the capacity. A more preferable range is 12 μm or less. Further, the lower limit value of the thickness of the negative electrode current collector is desirably 3 μm. On the other hand, the thickness of the positive electrode current collector is preferably 20 μm or less in order to increase the capacity. A more preferable range is 15 μm or less. Moreover, it is desirable that the lower limit value of the thickness of the positive electrode current collector be 3 μm.

As the negative electrode active material, for example, an oxide such as Nb ₂ O ₅ , LiTi ₂ O ₄ , Li ₄ Ti ₅ O ₁₂ or Li-containing silicon oxide, Li-containing nitride, or the like is applicable.

On the other hand, the positive electrode active material is not limited. MnO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , LiTi ₂ O ₄ , Li ₄ Ti ₅ O ₁₂ , LiFe ₂ O ₄ , lithium cobaltate, nickel acid lithium, lithium manganate, lithium nickel manganese oxide, nickel cobalt oxide, lithium cobalt manganese, metal oxides such as lithium nickel cobalt manganese oxide, or fluorinated graphite, inorganic compounds such as FeS _2, or polyaniline or polyacene structure Any material such as an organic compound is applicable. However, lithium-containing oxides in which lithium cobaltate, lithium nickelate, lithium manganate, mixtures thereof, or some of these elements are substituted with other metal elements are high in terms of operating potential and excellent cycle characteristics. In a non-aqueous electrolyte battery that may be used for a long period of time, lithium cobaltate is more preferable in terms of high capacity, low reactivity with the electrolyte and moisture, and chemical stability.

  A method for producing an electrode group using the positive electrode 3, the negative electrode 6, and the separator 8 described above will be described below.

  As shown in FIG. 2, a plurality of positive electrodes 3 and negative electrodes 6 are alternately stacked with a separator 8 interposed therebetween. The lamination method will be specifically described. One of the positive electrode 3 and the negative electrode 6 is accommodated in a bag-shaped separator 8. In the case of FIG. 2, the negative electrode 6 is accommodated so that the current deriving portion 4 protrudes from the opening end of the separator 8. The positive electrode 3 is laminated on the negative electrode 6 accommodated in the separator 8. At this time, the positive electrode active material-containing layer 2 of the positive electrode 3 is opposed to the negative electrode active material-containing layer 5 through the separator 8. Further, the current deriving portion 1 of the positive electrode 3 is protruded from the separator short side (the bottom portion of the separator 8) located on the side opposite to the separator short side from which the current deriving portion 4 protrudes. Thus, after laminating | stacking the negative electrode 6 and the positive electrode 3 alternately via the separator 8, the laminated body group shown in FIG. 3 is bundled together using the insulating tape 9 as needed. Get 10. The current lead-out part 1 of the positive electrode 3 protrudes from the negative electrode 6 and the separator 8 from one short side of the obtained laminated electrode group 10, and the current lead-out part 4 of the negative electrode 6 projects from the short side of the positive electrode 3 and the separator from the other short side. It protrudes more than 8.

  A positive electrode terminal is obtained by integrating the current deriving portion 1 of the positive electrode 3 by welding. Moreover, the negative electrode terminal is obtained by integrating the current deriving portion 4 of the negative electrode 6 by welding. The welding method is not particularly limited as long as the electrical connection between the current deriving portions is good. For example, laser welding, resistance welding, ultrasonic welding, or the like can be employed.

  After the non-aqueous electrolyte is held in the obtained laminated electrode group 10, the electrode group 10 is housed in a container so that the positive electrode terminal and the negative electrode terminal are drawn out of the container, whereby a non-aqueous electrolyte battery is obtained. obtain.

  According to the method according to the first embodiment, when the positive electrode and the negative electrode are stacked via the separator or the electrolyte layer, the active material non-formation part (current deriving part) of the current collector protrudes from two opposite sides. Since the positive and negative electrode terminals are formed by laminating and then integrating the non-active material formed part by welding, the positive and negative electrode ends made of aluminum having an average crystal particle diameter of 50 μm or less or an aluminum alloy having an average crystal particle diameter of 50 μm or less Bending and cutting during manufacturing of the child can be avoided. As a result, the manufacturing yield can be improved and the mass productivity can be improved. In addition, since the positive electrode terminal and the negative electrode terminal are sufficiently wide, the output characteristics at the time of rapid charge and rapid discharge can also be improved.

(Second Embodiment)
A battery manufacturing method according to the second embodiment will be described with reference to FIGS. Members similar to those shown in FIGS. 4A is a schematic diagram illustrating a process of cutting the current deriving portion of the positive electrode and the negative electrode, and FIG. 4B is a schematic diagram illustrating a process of integrating the current deriving portion of the positive electrode and the negative electrode by welding. FIG. FIG. 5 is a perspective view showing a container in which the stacked electrode group of FIG. 4 is accommodated. FIG. 6 is a perspective view showing a nonaqueous electrolyte battery manufactured by the method according to the second embodiment.

  First, after producing a positive electrode, a negative electrode, and a separator in the same manner as described in the first embodiment, these are laminated in the same manner as described in the first embodiment to obtain a laminated electrode group 10. . Next, as shown in FIG. 4A, the current deriving portion 1 of the positive electrode 3 is cut into a strip shape, and the current deriving portion 4 of the negative electrode 6 is cut into a strip shape. Thereafter, as shown in FIG. 4B, the current deriving portion 1 of the positive electrode 3 is integrated by welding to form the positive electrode terminal 11. Further, the current lead-out portion 4 of the negative electrode 6 is integrated by welding to form the negative electrode terminal 12. The welding method is as described in the first embodiment.

  A container in which the obtained stacked electrode group is stored is shown in FIG. As shown in FIG. 5, the container 13 is formed by subjecting the laminate film to an electrode group storage portion 14 formed of a rectangular recess formed by, for example, deep drawing or pressing, and processing of the laminate film. And a rectangular lid 15 made of a flat plate portion. When the laminate film is folded back along the dotted line toward the container, the electrode group storage portion 14 can be covered with the lid 15. The inner surface of the lid 15 is joined to the three sides 16a to 16c at the periphery of the opening of the electrode group storage portion 14 by, for example, heat fusion. FIG. 6 shows a state in which the lid body 15 is joined to the three sides 16 a to 16 c at the periphery of the opening of the electrode group housing portion 14 and is arranged with the lid body 15 facing down. As the laminate film, for example, a laminate film in which a metal layer is disposed between a thermoplastic resin layer and a resin layer can be used. Since the thermoplastic resin layer is positioned on the inner surfaces of the electrode group housing portion 14 and the lid body 15, the lid body 15 can be joined to the electrode group housing portion 14 by thermal fusion. The thermoplastic resin layer is made of, for example, polypropylene (PP) or polyethylene (PE). The metal layer is preferably an aluminum foil or an aluminum alloy foil. The resin layer is used to reinforce the metal layer and can be formed from a polymer such as nylon or polyethylene terephthalate (PET).

  The stacked electrode group 10 is accommodated in the electrode group accommodating portion 14 of the container 13 while holding the nonaqueous electrolyte. As shown in FIG. 6, the positive electrode terminal 11 is drawn out from between the short side 16 a at the periphery of the opening of the electrode group housing portion 14 and the lid 15, and the negative electrode terminal 12 is opened to the electrode group housing portion 14. It is pulled out from between the short side 16b on the opposite side of the peripheral edge of the part and the lid 15 to the outside. The long side 16c at the periphery of the opening of the electrode group housing portion 14 and the lid 15 are joined by heat fusion and then bent substantially vertically.

  According to the method according to the second embodiment, when the positive electrode and the negative electrode are stacked via the separator or the electrolyte layer, the active material non-formation part (current deriving part) of the current collector protrudes from the two opposite sides. Since the positive and negative electrode terminals are formed by laminating and then cutting the active material non-forming portion and then integrated by welding, the positive and negative electrode terminals made of aluminum or aluminum alloy having an average crystal particle diameter of 50 μm or less are produced. Bending and cutting can be avoided. In addition, the active material non-formation part includes a part that is not used as a positive / negative electrode terminal. During the laminating process, it is possible to attach foreign substances to the positive / negative electrode terminal or drop off the active material simply by holding this part. This can be avoided, and the handling of the positive and negative electrodes during the lamination process can be made easier. As a result, the manufacturing yield can be improved and the mass productivity can be improved.

  In addition, since the active material non-formation part is cut into a strip shape and integrated by welding, it is possible to reduce misalignment between the superimposed active material non-formation parts, and output during quick charge and rapid discharge A battery having excellent characteristics can be realized.

In the cutting step, the width A ₁ of the positive electrode terminal defined by the length in the direction orthogonal to the direction L ₁ in which the positive electrode terminal 11 is extracted from the container 13 and the direction orthogonal to the direction L _{2 in} which the negative electrode terminal 12 is extracted from the container 13. It is preferable that the width A ₂ of the negative electrode terminal defined by the length satisfies the following expressions (1) and (2).

0.1 ≦ (A ₁ / B ₁ ) <1 (1)
0.1 ≦ (A ₂ / B ₂ ) <1 (2)
However, B ₁ is a width of A ₁ and parallel to the electrode group 10 of the positive terminal 11, B ₂ is the width of A ₂ parallel to the electrode group 10 of the negative electrode terminal 12. In the case of FIG. 4, the width B ₁ of the electrode group is equal to the width B _{2 of the} electrode group.

(Third embodiment)
In the second embodiment described above, the current deriving portion is cut into a strip shape and then welded. However, the current deriving portion may be integrated by welding and then cut into a strip shape. According to the method according to the third embodiment, similarly to the second embodiment, bending and cutting during manufacturing of the positive and negative electrode terminals can be avoided, and handling of the positive and negative electrodes during the laminating process can be performed more easily. Is possible. Furthermore, since the current deriving portion is cut after being integrated by welding, the cutting can be performed more easily.

  In the first to third embodiments, an electrolyte layer may be used instead of the separator, or an electrolyte layer may be used in combination with the separator. When a solid electrolyte is used as the electrolyte layer, applications such as positive electrode / solid electrolyte / separator / negative electrode, positive electrode / separator / solid electrolyte / negative electrode, positive electrode / solid electrolyte / separator / solid electrolyte / negative electrode are possible.

  The separator desirably has an area that is 1.01 times or more and 1.1 times or less the area facing the positive electrode active material-containing layer or the area facing the negative electrode active material-containing layer.

  The area ratio of the electrolyte layer to the separator is desirably 0.85 or more and 1 or less.

[Example]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1
A positive electrode active material made of LiCoO ₂ , a conductive auxiliary material made of carbon, and a binder made of polyvinylidene fluoride (PVdF) were mixed using a solvent to prepare a slurry. A positive electrode active material is contained on both sides of the positive electrode current collector by applying slurry to both sides of the positive electrode current collector made of a sheet-like aluminum foil (purity 99.99%) having a thickness of 15 μm and an average crystal particle diameter of 50 μm A positive electrode having a layer formed thereon was produced. The obtained positive electrode was cut into a rectangular sheet. In addition, slurry was not applied to one side in the short side direction of the positive electrode current collector, and a current derivation unit was formed.

A negative electrode active material made of Li ₄ Ti ₅ O ₁₂ , a conductive auxiliary material made of carbon, and a binder made of polyvinylidene fluoride (PVdF) were mixed using a solvent to prepare a slurry. A negative electrode on which a negative electrode active material-containing layer is formed by applying slurry on both sides of a negative electrode current collector made of a sheet-like aluminum foil (purity 99.99%) having a thickness of 15 μm and an average crystal particle diameter of 50 μm Produced. The obtained negative electrode was cut into a rectangular sheet. In addition, slurry was not applied to one side in the short side direction of the negative electrode current collector, and a current deriving unit was formed.

  Next, a bag-shaped separator made of a polyethylene porous film was prepared, and the negative electrode was housed in the bag-shaped separator. The negative electrode and the positive electrode housed in the bag-like separator were stacked in parallel in the order of negative electrode / separator / positive electrode, and fixed with an insulating tape. At this time, the areas of the negative electrode active material-containing layer and the positive electrode active material-containing layer were the same, and the area of the current deriving portion that did not form the active material was also the same. In addition, the width of the separator is sufficient to cover all the positive and negative active materials, but all the portions not forming the active material are not covered. Although the positive and negative electrode current collector and the separator are parallel, the current deriving part of the positive electrode protrudes from the negative electrode and the separator on one short side of the laminate, and the negative electrode current deriving part is formed on the opposite short side of the positive electrode and the separator. Than protruding.

  The current lead-out portion of the positive electrode was integrated by laser welding to form a positive electrode terminal. Further, the current lead-out portion of the negative electrode was integrated by laser welding to form a negative electrode terminal. Through the above steps, the above-described electrode group shown in FIG. 3 was obtained.

  The electrode group thus obtained was impregnated with a non-aqueous electrolyte and then sealed in a container to produce a lithium ion secondary battery with a designed battery capacity of 300 mAh.

(Examples 2-3)
Before the positive and negative current deriving portions were integrated by laser welding in the electrode group manufacturing process of Example 1, the positive current deriving portion was cut into a strip shape, and the negative current deriving portion was cut into a strip shape. . Next, the current lead-out part of the positive electrode was integrated by laser welding to form a positive electrode terminal. Further, the current lead-out portion of the negative electrode was integrated by laser welding to form a negative electrode terminal. Through the above steps, the electrode group shown in FIG. 4B was obtained.

  After impregnating the electrode group obtained in this manner with a non-aqueous electrolyte, the lithium ion secondary battery having the structure shown in FIG. 6 and having a design battery capacity of 300 mAh is sealed by sealing in a container. Manufactured.

Example 4
In the electrode group manufacturing process of Example 1 described above, the positive and negative current deriving portions were integrated by laser welding, and then the positive current deriving portion was cut into a strip shape to form a positive electrode terminal. Moreover, the negative electrode current lead-out portion was cut into a strip shape to form a negative electrode terminal.

  After impregnating the electrode group obtained by the above steps with a non-aqueous electrolyte, the lithium ion secondary battery having the structure shown in FIG. 6 and having a design battery capacity of 300 mAh is sealed by sealing in a container. Manufactured.

(Comparative example)
As shown in FIG. 7A, on both surfaces excluding both ends 18 of a positive electrode current collector 17 made of a sheet-like aluminum foil (purity 99.99%) having a thickness of 15 μm and an average crystal particle diameter of 50 μm. By applying the slurry prepared in the same manner as in Example 1, a positive electrode in which the positive electrode active material-containing layer 19 was formed on both surfaces of the positive electrode current collector 17 was produced.

  Next, as shown in FIGS. 7B and 7C, a strip-shaped positive electrode 21 having tabs 20 on the short sides was formed by punching.

  Further, as shown in FIG. 8A, both end portions 23 of the negative electrode current collector 22 made of a sheet-like aluminum foil (purity 99.99%) having a thickness of 15 μm and an average crystal particle diameter of 50 μm were excluded. By applying the slurry prepared in the same manner as in Example 1 on both surfaces, a negative electrode in which the negative electrode active material-containing layer 24 was formed on both surfaces of the negative electrode current collector 22 was produced.

  Next, as shown in FIGS. 8B and 8C, a strip-shaped negative electrode 26 having tabs 25 on the short sides was formed by punching.

  Next, as shown in FIG. 9, the negative electrode 26 was stored in a bag-like separator 27 made of a polyethylene porous film so that the tab 25 protruded from the opening of the separator 27. The negative electrodes 26 already stored in the separator 27 and the positive electrodes 21 were alternately stacked. At that time, the tab 25 of the negative electrode 26 protruded from the positive electrode 21 on one short side of the laminate, and the tab 20 of the positive electrode 21 protruded from the negative electrode 26 on the other short side.

  Subsequently, the tab 20 of the positive electrode 21 was integrated by laser welding, and the tab 25 of the negative electrode 26 was integrated by laser welding. The obtained electrode group was fixed with an insulating tape 28.

  The electrode group thus obtained was impregnated with a non-aqueous electrolyte and then sealed in a container to produce a lithium ion secondary battery with a designed battery capacity of 300 mAh.

  The obtained secondary battery was charged and discharged once at 1 C current in a constant temperature room at 25 ± 3 ° C. and a relative humidity of 70% or less, then rapidly discharged at 20 C current, and the pair of electric capacities discharged at that time. A relative value with respect to the initial charge electricity amount was obtained. The results are shown in Table 1 below. The evaluation results in the table are average values when six batteries are produced.

In addition, the number of manufacturing defects in which terminals and tabs were cut during battery manufacture and the battery could not be manufactured is also shown in Table 1 below (the parameter is 100). Further, the length ratios (A ₁ / B ₁ ) and (A ₂ / B ₂ ) are also shown in Table 1 below. The width B ₁ of the electrode group was equal to the width B _{2 of the} electrode group.

  As is apparent from Table 1, in the manufacturing methods of Examples 1 to 3, since the positive electrode and the negative electrode were laminated, the active material non-formation part of the current collector was integrated by welding to form a terminal. In addition, it can be seen that the positive and negative terminals are less likely to be deformed and cut, and the mass productivity is excellent. On the other hand, in the manufacturing method of the comparative example, after forming the positive and negative electrode tabs by punching, the positive and negative electrode tabs are laminated to produce an electrode group. Many failures occurred.

  In addition, from the comparison between Examples 2 and 4, Example 2 in which the active material non-formation part of the current collector is cut into a strip shape and then integrated by welding to form the terminal is relative to the initial charge electricity amount. It was found that the high current characteristics were excellent.

  As described above, according to the present invention, it is possible to provide a battery electrode structure with good production and production efficiency and high power density.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The schematic diagram which shows the manufacturing process of a positive electrode, a separator, and a negative electrode. The schematic diagram which shows the process of laminating | stacking a positive electrode, a separator, and a negative electrode. The perspective view which shows the laminated electrode group manufactured by the method which concerns on 1st Embodiment. The schematic diagram which shows the process of forming a positive / negative electrode terminal. The perspective view which showed the container in which the laminated electrode group of FIG. 4 is accommodated. The perspective view which shows the nonaqueous electrolyte battery manufactured by the method which concerns on 2nd Embodiment. The perspective view which shows the manufacturing process of the positive electrode in the battery of a comparative example. The perspective view which shows the manufacturing process of the negative electrode in the battery of a comparative example. The perspective view which shows the preparation process of the electrode group in the battery of a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,4 ... Current derivation | leading-out part, 2 ... Positive electrode active material containing layer, 3 ... Positive electrode, 5 ... Negative electrode active material containing layer, 6 ... Negative electrode, 8 ... Separator, 9 ... Insulating tape, 10 ... Multilayer electrode group, 11 ... Positive terminal 12, negative electrode terminal 13, container 14, electrode group storage unit 15, lid.

Claims (5)

A current lead-out portion is formed at one end, and is formed excluding at least the current lead-out portion of the positive electrode current collector made of aluminum or aluminum alloy having an average crystal particle diameter of 50 μm or less and a thickness of 20 μm or less and the positive electrode current collector. A plurality of positive electrodes including a positive electrode active material-containing layer, a negative electrode current collector having an average crystal particle diameter of 50 μm or less and a thickness of 20 μm or less, a negative electrode current collector having a current lead-out portion formed at one end, and the negative electrode collector A plurality of negative electrodes including a negative electrode active material-containing layer formed excluding at least the current deriving portion of an electric body, and a separator and an electrolyte layer between the positive electrode active material-containing layer and the negative electrode active material-containing layer. Laminating so that at least one member is interposed, and projecting the current deriving portion of the positive electrode from the negative electrode and the member on one side of the laminate, A step of also protrudes from the positive electrode and the member of the current lead portion of the negative electrode at the opposite side edges of the laminate One,
Integrating the current deriving portion of the positive electrode by welding to form a positive electrode terminal, and integrating the current deriving portion of the negative electrode by welding to form a negative electrode terminal;
Cutting each of the positive terminal and the negative terminal into strips;
A method of manufacturing a battery comprising: storing the obtained electrode group in a container so that the positive electrode terminal and the negative electrode terminal are drawn out of the container. A current lead-out portion is formed at one end, and is formed excluding at least the current lead-out portion of the positive electrode current collector made of aluminum or aluminum alloy having an average crystal particle diameter of 50 μm or less and a thickness of 20 μm or less and the positive electrode current collector. A plurality of positive electrodes including a positive electrode active material-containing layer, a negative electrode current collector having an average crystal particle diameter of 50 μm or less and a thickness of 20 μm or less, a negative electrode current collector having a current lead-out portion formed at one end, and the negative electrode collector A plurality of negative electrodes including a negative electrode active material-containing layer formed excluding at least the current deriving portion of an electric body, and a separator and an electrolyte layer between the positive electrode active material-containing layer and the negative electrode active material-containing layer. Laminating so that at least one member is interposed, and projecting the current deriving portion of the positive electrode from the negative electrode and the member on one side of the laminate, A step of also protrudes from the positive electrode and the member of the current lead portion of the negative electrode at the opposite side edges of the laminate One,
A step of cutting the respective said current deriving unit of the current deriving unit and the negative electrode obtained by the projection of the is protruded the positive electrode strip,
After the cutting, forming the positive electrode terminal by integrating the current deriving portion of the positive electrode by welding, and integrating the current deriving portion of the negative electrode by welding to form a negative electrode terminal;
A method of manufacturing a battery comprising: storing the obtained electrode group in a container so that the positive electrode terminal and the negative electrode terminal are drawn out of the container. The cutting step, the direction in which the positive electrode terminal width A ₁ and the negative terminal of said positive terminal defined by the length of the direction perpendicular to the direction drawn from the container perpendicular to the direction drawn from the vessel length the negative terminal of the width a ₂ is the following (1), (2) method for producing a battery according to claim 1 or 2, wherein the performed so as to satisfy the formula specified in of.
0.1 ≦ (A ₁ / B ₁ ) <1 (1)
0.1 ≦ (A ₂ / B ₂ ) <1 (2)
Where B ₁ is the width of the electrode group parallel to the width A _{1 of the} positive terminal, and B ₂ is the width of the electrode group parallel to the width A ₂ of the negative terminal. The separator has an area that is 1.01 times or more and 1.1 times or less of an area facing the positive electrode active material-containing layer or an area facing the negative electrode active material-containing layer. 3. The method for producing a battery according to any one of 3 above. The area ratio with respect to the separator of the electrolyte layer is 0.85 or higher, according to claim 1-4 method of manufacturing a battery according to any one of the preceding, wherein the 1 or less.

Images