JP2014060016A - Method of manufacturing battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a battery which allows for enhancement of production efficiency, because electrolyte does not overflow from the aperture of a film armor material.SOLUTION: A method of manufacturing a battery includes a housing step for housing an electrode laminate 60, laminating a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes via a separator therebetween, in a film armor material 90 having an aperture 93, an opening step for widening the opening space (S) of the aperture by applying a stress to the film armor material 90, a liquid injection step for injecting electrolyte from the aperture 93 in a state where the opening space (S) of the aperture 93 is widened by the opening step, and an impregnation step for performing vacuum impregnation in a state where the opening space (S) of the aperture 93 is widened by the opening step, following to the liquid injection step.

Description

  The present invention relates to a method for manufacturing a secondary battery such as a lithium ion battery having a structure in which an electrode laminate in which a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are laminated via a separator is accommodated in a film exterior material.

  In recent years, due to environmental problems, clean energy obtained from wind power generation, solar power generation, and the like that can be used for home use such as a detached house and industrial use such as transportation equipment and construction equipment has attracted attention. However, the clean energy has a problem that the output varies greatly depending on the situation. For example, energy from solar power generation can be obtained during the day when the sun is rising, but not at night after the sun has set.

  In order to stabilize the output of clean energy, a technique for temporarily storing clean energy in a battery is used. For example, solar energy stored in a battery can be used at night after the sun goes down. As a battery for storing such clean energy, a lead battery is generally used. However, a lead storage battery is generally large in size and has a drawback of low energy density.

  Therefore, in recent years, lithium ion secondary batteries that can operate at room temperature and have high energy density have attracted attention. In addition to the characteristic that the energy density is high, the lithium ion secondary battery also has a feature that it has excellent responsiveness because of its low impedance.

  As an example of the internal structure of such a lithium ion secondary battery, an electrode laminate in which a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are laminated via separators, and an electrolyte solution are rectangular in a plan view. A structure housed in a laminate film exterior material is known.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2001-15099) specifically discloses a method for manufacturing a battery having the above-described structure. According to this method, a process for mounting and incorporating a battery element in an exterior film body is disclosed. And a step of sealing the opening after injecting an electrolyte from the other end opening side of the exterior film body in which the battery element is built-in and attached, and the exterior film body The opening side of the outer film body is set larger than the required shape and size, and a step of welding and sealing leaving a part of the area adjacent to the built-in / mounted battery element, and the opening on the front end side of the exterior film body are electrolyzed. As a liquid injection port, after injecting an electrolytic solution to the battery element side through a metering pump, impregnating under reduced pressure, and non-welded sealing left in a region adjacent to the battery element injected and impregnated with the electrolytic solution Weld and seal the part Method for manufacturing a thin battery and having a degree, is disclosed.
JP 2001-15099 A

  In the battery manufacturing method disclosed in Patent Document 1, the opening side of the exterior film body is set larger than the required shape and dimensions, and the battery element is sealed in the exterior film body. After the step of performing, the exterior film body in the vicinity of the opening is cut.

  According to the conventional manufacturing method as described above, since an outer film body larger than the battery as a finished product is used, there is a problem that the cost is increased accordingly.

  Therefore, in order to avoid the extra cost as described above, if only the battery that is a finished product is used as the film exterior material, this time, after injecting the electrolyte from the opening, In the impregnation step of performing vacuum impregnation to replace the air contained in the electrolyte and the electrolyte, the expanded air does not escape as expected, pushes up the electrolyte surface, and the electrolyte from the opening of the film exterior material Overflows and a problem arises that the production efficiency of the battery decreases.

  The problem that the electrolyte overflows from the opening of the film exterior material as described above occurs not only in the impregnation process but also in the sealing process of sealing the opening of the film exterior material. Sometimes.

  The present invention solves the above-described problems, and a battery manufacturing method according to the present invention includes a film exterior material having an opening, and a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are separators. The opening process of expanding the opening area of the opening by applying a stress to the film exterior material, and the opening area of the opening by the opening process An infusion process for injecting an electrolytic solution from the opening in the expanded state, and an impregnation in which vacuum impregnation is performed after the injecting process and the opening area of the opening is expanded by the opening process. And a process.

  In addition, the battery manufacturing method according to the present invention further includes a sealing step of sealing the opening under vacuum after the impregnation step.

  In the battery manufacturing method according to the present invention, the degree of vacuum in the impregnation step is higher than the degree of vacuum in the sealing step.

  Moreover, the manufacturing method of the battery which concerns on this invention applies stress to the said film exterior material with the jig | tool which performs adsorption | suction in the said opening process.

  In the battery manufacturing method according to the present invention, in the opening step, stress is applied to the film exterior member with a jig that holds the shape of the opening.

  In the battery manufacturing method according to the present invention, the separator is in a bag shape.

  According to the battery manufacturing method of the present invention, since the vacuum impregnation is performed in a state where the opening area of the opening portion is widened by the opening step, a sufficient volume for storing the electrolyte solution in the film exterior member is ensured. In the impregnation process, the expanded air does not escape as expected, and even if the electrolyte surface is pushed up, the electrolyte does not overflow from the opening of the film exterior material, and the manufacturing efficiency is improved. .

  By making the degree of vacuum in the impregnation step higher than the degree of vacuum in the sealing step, the electrolyte does not overflow from the opening of the film exterior material even in the sealing step.

It is a figure explaining the manufacturing process of the battery which concerns on embodiment of this invention. It is a figure explaining the manufacturing process of the battery which concerns on embodiment of this invention. It is a figure explaining the manufacturing process of the battery which concerns on embodiment of this invention. It is a figure which shows the battery 100 manufactured by the manufacturing method of the battery which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 are diagrams for explaining a battery manufacturing process according to an embodiment of the present invention. In the present embodiment, as the battery 100, a lithium ion secondary battery, which is one type of electrochemical element, in which charging / discharging is performed by moving lithium ions between a negative electrode and a positive electrode will be described.

  The battery 100 manufactured by the battery manufacturing method according to the embodiment of the present invention includes an electrode stack 60 in which a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are stacked via a separator, and an electrolyte solution 80. It has a structure accommodated in a rectangular laminate film exterior material 90 in plan view.

  Each sheet-like positive electrode is conductively connected to the positive electrode extraction tab 120 via the current collector 62. Similarly, each sheet-like negative electrode is also conductively connected to the negative electrode lead tab 130 via the current collector 63.

  When the battery 100 is completed, the positive electrode pull-out tab 120 and the negative electrode pull-out tab 130 are pulled out from one end (side) of the battery 100.

  The laminate film exterior material 90 is made of a metal laminate film having a heat-sealing resin layer. In the present embodiment, the laminate film exterior member 90 is a side opposite to the side from which the positive electrode pull-out tab 120 and the negative electrode pull-out tab 130 are drawn, with two rectangular metal laminate films facing the heat-sealing resin layer. A structure is adopted in which the heat welding portion 91 corresponding to the side from which the positive electrode pulling tab 120 and the negative electrode pulling tab 130 are drawn and the two sides 92 adjacent to the heat welding portion 91 are welded so that 93 becomes an opening. Has been.

  FIG. 1 shows a process of housing the electrode laminate 60 such that when the electrode laminate 60 is accommodated in the laminate film exterior material 90, the positive electrode extraction tab 120 and the negative electrode extraction tab 130 are extracted from the side opposite to the opening 93. Is shown.

  Note that metal pieces such as the positive electrode pull-out tab 120 and the negative electrode pull-out tab 130 drawn from the battery 100 made of the laminate film exterior material 90 are referred to as “drawer tabs”, and a separator or electrolyte solution is provided inside the laminate film exterior material 90 A sheet-like positive electrode or a sheet-like negative electrode laminated via 80 or the like is referred to as an “electrode”.

  Further, in the electrode laminate 60, in addition to the above-described one in which a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are laminated via a separator, a sheet-like positive electrode and a sheet-like negative electrode are laminated via a separator. The thing which makes a laminated body by winding a thing and compressing this is also contained.

  Further, the separator is not limited to a rectangular sheet-like one, and a bag-like one interposed between a sheet-like positive electrode and a sheet-like negative electrode may be used by accommodating an electrode. In particular, the bag-shaped separator has an overlapped portion formed by heat fusion, which is not found in a sheet-shaped separator, so that expanded air may be difficult to escape compared to a sheet-shaped separator. The effect of the present invention can be enjoyed more. In the case where the separator is formed into a bag shape, it is preferable that a part of the separator on the side corresponding to the opening is not thermally fused, particularly intermittently, in consideration of easiness of passing the electrolyte solution. It is preferable.

Further, the laminate film is a side where the sheet of the rectangular metal laminate film is folded, and the positive electrode pull-out tab 120 and the negative electrode pull-out tab 130 are taken out from the portion other than the folded portion, and the positive electrode pull-out tab 120 and the negative electrode pull-out tab 130 are taken out. It is good also as a structure which makes an opening other than.

  FIG. 2 is a view for explaining an opening process for expanding the opening area by applying stress to the opening 93 of the laminate film exterior member 90 containing the electrode laminate 60. In FIG. 2 and subsequent figures, the laminate film exterior material 90 is shown transparently.

  In FIG. 2, the direction of stress applied to the laminate film exterior member 90 in order to increase the opening area of the opening 93 is the direction of the arrow. In the present invention, the opening area S (shaded portion in the figure) of the opening 93 is ensured by such an opening process.

Here, when the width of the opening of the laminate film is A (mm) and the height (thickness) of the electrode laminate 60 accommodated in the laminate film is B (mm), S ≧ (A × B) / 2 (Mm ²
) Is preferable.

  In order to ensure the stress applied to the laminate film exterior member 90 in the opening step as described above, this may be performed by a jig that performs suction near the opening 93, or the opening 93, for example. This may be done with a jig that holds the shape.

  FIG. 3 is a view showing a state after the liquid pouring step, through an impregnation step in which vacuum impregnation is performed in a state where the opening area of the opening 93 is widened by the opening step. This impregnation step is performed by placing the electrode laminate 60 and the laminate film exterior member 90 containing the electrolyte solution 80 in a predetermined vacuum chamber (not shown).

  In the present invention, since the impregnation step of performing the vacuum impregnation is performed in a state where the opening area of the opening 93 is widened by the opening step, the bubbles in the electrode laminate 60 and the electrolyte solution 80 are easily ruptured. Even if the expanded air pushes up the electrolytic solution surface because the electrolytic solution tends to flow around to the opposite side of the opening 93, the electrolytic solution overflows from the opening 93 of the film exterior member 90, or the portion to be sealed later A large amount of electrolyte does not adhere, and the production efficiency is improved.

  By the way, when manufacturing a battery, it is necessary to perform the sealing process which seals the opening part 93 of the film exterior | packing material 90 under a vacuum following the above impregnation processes. In the sealing step, a heat-sealing resin layer of the film exterior material 90 is applied by applying heat to the shaded portion in FIG. 4 in a state where a predetermined degree of vacuum is maintained in a predetermined vacuum chamber (not shown). To seal the opening 93. Thereby, the battery 100 in a state in which the positive electrode extraction tab 120 and the negative electrode extraction tab 130 are extracted from the laminate film packaging material 90 in which the electrode laminate 60 and the electrolyte solution 80 are enclosed is completed. Here, in such a battery, the more electrolyte solution enclosed in the laminate film outer packaging material is, the more preferable, but on the other hand, in order to increase the electrolyte solution, an excessive space is excessive rather than the shape of the electrode laminate. If it is provided, the shape of the battery becomes large, which is not preferable.

  Therefore, the degree of vacuum in the impregnation process is preferably set higher than the degree of vacuum in the sealing process. By setting in this way, it is possible to prevent the trouble that the electrolytic solution 80 overflows from the opening 93 of the laminate film exterior material 90 even in the sealing process, and the manufacturing efficiency of the battery 100 can be improved. It becomes.

As described above, according to the battery manufacturing method of the present invention, since the vacuum impregnation is performed in a state where the opening area of the opening is widened by the opening step, a sufficient volume for storing the electrolyte in the film exterior material is secured. In the impregnation process, the expanded air does not escape as expected, and even if the electrolyte surface is pushed up, the electrolyte does not overflow from the opening of the film exterior material, and the production efficiency is improved. improves.

  By making the degree of vacuum in the impregnation step higher than the degree of vacuum in the sealing step, the electrolyte does not overflow from the opening of the film exterior material even in the sealing step.

60 ... Electrode laminated body, 62 ... Current collector, 63 ... Current collector, 80 ... Electrolyte, 90 ... Laminate film exterior material, 91 ... Thermal welding part, 92. ..Heat welding part, 93 ... Opening part, 100 ... Battery, 110 ... Battery body part, 120 ... Positive electrode extraction tab, 130 ... Negative electrode extraction tab

Claims (6)

An accommodating step of accommodating an electrode laminate in which a plurality of sheet-like positive electrodes and a plurality of sheet-like negative electrodes are laminated via separators on a film exterior material having an opening,
An opening step of expanding the opening area of the opening by applying stress to the film exterior material, and injecting the electrolyte from the opening in a state where the opening area of the opening is expanded by the opening step A liquid injection process;
After the liquid injection step, an impregnation step of performing vacuum impregnation in a state where the opening area of the opening is expanded by the opening step;
A method of manufacturing a battery having The battery manufacturing method according to claim 1, further comprising a sealing step of sealing the opening under vacuum after the impregnation step. The battery manufacturing method according to claim 2, wherein a degree of vacuum in the impregnation step is higher than a degree of vacuum in the sealing step. The battery manufacturing method according to any one of claims 1 to 3, wherein in the opening step, stress is applied to the film exterior member by a jig for performing adsorption. 4. The battery manufacturing method according to claim 1, wherein, in the opening step, stress is applied to the film exterior member with a jig that holds the shape of the opening. 5. The battery manufacturing method according to claim 1, wherein the separator is in a bag shape.

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