JP4187875B2 - Thin battery manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a thin battery.
[0002]
[Prior art]
For example, secondary batteries such as non-aqueous solvent batteries are widely used as power sources for mobile phones and video cameras. In addition, power supply batteries are required to be small in size, light in weight, high in voltage, high in capacity, etc., as the devices are downsized and high performance. In response to such demands, for example, polymer batteries having a thickness of about 1 mm are known (Japanese Patent Laid-Open Nos. 3-230474, 3-225765, etc.).
[0003]
FIG. 3 is a cross-sectional view showing the configuration of the main part of the battery. The battery element 1 is inserted and arranged in an airtight manner between the sheet-like positive electrode 1a and the sheet-like negative electrode 1b facing each other and the electrodes 1a and 1b. Sheet-shaped electrolyte system 1c, a current collector sheet (not shown) that is in electrical contact with each of the electrodes 1a and 1b, and a positive electrode terminal separated from the current collector (not shown) of the positive electrode 1a and the negative electrode 1b 1a ′ and negative electrode terminal 1b ′ are extended (derived) from the exterior film body 2.
[0004]
And this kind of thin battery is generally manufactured as follows. That is, a battery element is filled and impregnated with a predetermined amount of electrolytic solution, and the battery element is positioned, accommodated and mounted (sealed) in an exterior film body (exterior covering body / bag body) opened at one end. . Thereafter, a thin battery having a configuration in which the exterior film body opening is heat-sealed (welded) and hermetically sealed is manufactured.
[0005]
FIG. 4 schematically shows the operation of filling and impregnating (injecting) the electrolytic solution into the battery element 1, and by immersing the battery element 1 in the electrolytic solution tank 4 containing the electrolytic solution 3. The electrolyte is filled and impregnated. Here, the filling (injection) / impregnation amount of the electrolytic solution into the battery element 1 is determined by the immersion time of the battery element 1, so that a predetermined amount of electrolytic solution filling (injection) / impregnation is performed by selecting / controlling the immersion time. ing.
[0006]
In the production of the thin battery, there is a method of folding the exterior film in half with the battery element interposed therebetween, and melt-sealing and sealing the edge portions that contact each other to form an exterior film body. Moreover, about a battery element, the winding body wound and formed in the cylinder shape may be pressed and flattened.
[0007]
Incidentally, the sheet-like positive electrode 1a is formed lithium-containing metal oxide capable of absorbing and releasing lithium ions (such as lithium Man gun composite oxide, lithium-containing cobalt oxide) and the like and manganese dioxide as a main component. The sheet-like negative electrode 1b is a lithium metal or lithium are formed by such a carbonaceous material and a lithium alloy system of occluding and releasing further polymer over the electrolyte system. 1c, the separator substrate made of non-woven polypropylene fabric, An ethylene carbonate solution such as a lithium salt: a structure in which a nonaqueous electrolyte is impregnated or supported.
[0008]
[Problems to be solved by the invention]
However, in the case of the above thin battery manufacturing method, inconvenience is recognized in terms of product quality, mass productivity, and the like. That is, in the manufacturing process of the thin battery, the battery element 1 is immersed in the electrolyte solution 3 for a certain period of time, and the battery element 1 is impregnated and filled with the electrolyte solution.
[0009]
However, since the battery element 1 itself has variations in configuration and quality, even when immersed in the electrolyte 3 for a certain period of time, variations in the amount of impregnation and filling of the electrolyte are recognized. There's a problem. Further, the operation of immersing the battery element 1 in the electrolyte solution 3 for a certain period of time and impregnating and filling the electrolyte solution is not only problematic in terms of productivity and efficiency, but is also accommodated in the electrolyte solution tank 4. There is also a risk of causing contamination and denaturation of the electrolyte solution 3.
[0010]
In order to eliminate the occurrence of such problems, a method has been attempted in which the battery element 1 is sealed (built-in / mounted) in the exterior film body 2 and then the injection / impregnation of the electrolytic solution is repeated a plurality of times. However, the electrolyte injection operation divided into a plurality of times results in an increase in the time required for the electrolyte injection, and the volatilization of the injected electrolyte components and the accuracy of the electrolyte injection amount are likely to be impaired (divided). This raises problems such as the accumulation of injection volume errors due to electrolyte injection, and is not a sufficient solution.
[0011]
The present invention has been made in view of the above circumstances, and aims to provide a mass-produced manufacturing method of a thin battery with high reliability as well as a reduction in size and weight.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention , a battery element is mounted and built in an exterior film body having one end set larger than a required shape and size and opened, and an electrode terminal of the battery element is led out to the other end side of the exterior film body. a step of sealing the other end of the outer film material and a step of welding sealing while leaving a portion of the region where the opening portion side, adjacent the leading Symbol built-mounted to the battery element of the outer film body The step of injecting the electrolyte solution in the normal pressure state through the metering pump to the battery element side using the opening on the front end side of the exterior film body as the electrolyte solution injection port, and the exterior film body infused with the electrolyte solution are installed From the normal pressure state to the reduced pressure state, the step of impregnating the battery element with the electrolytic solution, and the space in which the exterior film body in which the battery element impregnated with the electrolytic solution is mounted and incorporated is installed from the reduced pressure state to the normal pressure state. Pressure state A method for producing a thin battery which is characterized in that a step of welding sealing the non-weld sealing portion left in a region adjacent to the battery element.
[0013]
According to a second aspect of the present invention, in the method for manufacturing a thin battery according to the first aspect, a plurality of battery elements are built in and attached to each other in the exterior film body, and are cut and separated after welding sealing. Features.
[0014]
According to a third aspect of the present invention, in the thin battery manufacturing method according to the first or second aspect, the opening on the front end side of the exterior film body for injecting the electrolyte into the battery element side is processed into a funnel shape. And
[0015]
According to a fourth aspect of the present invention, in the method for producing a thin battery according to any one of the first to third aspects, the exterior film body is a laminate film in which resin layers are provided on both surfaces of a metal layer.
[0016]
According to a fifth aspect of the present invention, in the method for manufacturing a thin battery according to any one of the first to fourth aspects, a heat-fusible resin layer is provided in a sealed region of the exterior film body. And
[0017]
The inventions of claim 1 to claim 5 are: (a) a longer opening part of the exterior film body having one end opened with respect to the battery element to be built-in / mounted; and (b) a battery to be built-in / mounted. (C) The electrolyte element is supplied to the battery element in a normal pressure state with a metering pump using the longer opening side as an electrolyte inlet, leaving a part of the region (part) adjacent to the element. (D) After impregnation under vacuum or reduced pressure after filling the electrolyte, the non-welded sealing part left in the region (part) adjacent to the battery element in the normal pressure state is welded and sealed (E) After the entire welding and sealing, it is essential to cut the outer layer film body at a region having a predetermined shape and size.
[0018]
That is, in the manufacturing process of a thin battery, an opening side serving as an electrolyte injection port into the exterior film body is extended from the region to be sealed and cut at the final stage, and this extended exterior film body While using the area as an electrolyte injection port (funnel) part, by injecting the electrolyte with a metering pump and then impregnating under reduced pressure, a certain amount of electrolyte can be injected with high accuracy It is what.
[0019]
In the invention according to any one of claims 1 to 5, the battery element is a laminate of a sheet-like positive electrode and a sheet-like negative electrode interposing a sheet-like electrolyte that also serves as a battery separator, or a sheet-like electrolyte that also serves as the separator. Examples thereof include a plate-like body obtained by rolling a wound / wound body of the inserted sheet-like positive electrode and the sheet-like negative electrode.
[0020]
That is, a sheet positive electrode obtained by laminating an active material such as a metal oxide, a non-aqueous electrolyte and an electrolyte-retaining polymer on a current collector, an active material that occludes and releases lithium ions, a non-aqueous electrolyte, and A sheet-like negative electrode formed by laminating a negative electrode containing an electrolyte-retaining polymer on a current collector, and an electrolyte-retaining polymer-electrolyte system that functions as a separator (for example, a polymer such as hexafluoropropylene-vinylidene fluoride copolymer and lithium The system is made of an ethylene carbonate solution such as a salt, a non-aqueous electrolyte, and the like.
[0021]
Here, examples of the active material for the sheet-like positive electrode include lithium manganese composite oxide, manganese dioxide, lithium-containing cobalt oxide, lithium-containing nickel cobalt oxide, lithium-containing amorphous vanadium pentoxide, and chalcogen compound. It is done. Examples of the negative electrode active material include baked products such as bisphenol resin, polyacrylonitrile, and cellulose, and fired products of coke and pitch. These include natural or artificial graphite, carbon black, acetylene black, ketjen black, nickel powder. Further, a form containing nickel powder or the like may be adopted.
[0022]
Further, the polymer electrolyte system can be used in nonaqueous solvents such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, lithium perchlorate, lithium hexafluorophosphate, lithium borotetrafluoride. In addition, lithium arsenic hexafluoride, lithium trifluoromethanesulfonate and the like are dissolved in about 0.2 to 2 mol / l.
[0023]
Examples of the sheet positive electrode current collector include aluminum foil, aluminum mesh, aluminum expanded metal, aluminum punch metal, etc., and the sheet negative electrode current collector includes copper foil, copper mesh, Examples include copper expanded metal and copper punch metal.
[0024]
In the invention of claim 1 to claim 5, the exterior film body for sealing the battery element is a bag-like body in which one end is opened and at least the sealing / fusion portion is formed of a heat-fusible resin. is there. In other words, each electrode terminal of the sheet-shaped (plate-shaped) battery element is sealed and led out and has a one-end opening shape having a width and length that can be sealed, and the length is longer than usual in the opening direction. Is also set longer.
[0025]
The exterior film body may be formed in a bag-like body in advance, but the exterior film is folded in half, and the battery element is sandwiched while the electrode terminal is led out between them, so that both sides of the exterior film body are in contact with each other. The surfaces may be heat-sealed to form a bag-like body during the assembly process. However, in any case, after the battery element is placed in the built-in / mounted state, a part of the opening side region (part) of the exterior film body adjacent to the battery element is left (the electrolyte injection port to the battery element side) Therefore, it is necessary to primarily weld and seal the exterior film body.
[0026]
Examples of the film forming the exterior film body include a polyimide resin film, a polypropylene resin film, and a laminate type in which resin layers are provided on both sides of the metal layer in consideration of moisture resistance. Then, when these films are used as a material for an exterior film body, or when an exterior film body is fused and sealed after injection of an electrolytic solution, a hot-melt adhesive layer is provided on the surface to be sealed against each other. It is desirable to use a film in which the surfaces to be interposed or at least the surfaces that are in contact with each other and sealed are heat-melt type resin layers in advance.
[0027]
According to the first to fifth aspects of the present invention, since a predetermined amount of electrolyte can be easily and accurately injected and impregnated under reduced pressure in the polymer battery manufacturing process, a high-quality battery can be manufactured with high yield. That is, a part of the exterior film body is used as an injection reservoir for electrolytic solution, and a predetermined amount of electrolytic solution is supplied by a metering pump, while the impregnation system of the electrolytic solution is maintained in a reduced pressure (vacuum) state. Therefore, impregnation after injection and filling of electrolyte such as battery elements is easily performed within a short time by vacuum impregnation treatment, so that good productivity is maintained and a certain amount of electrolyte can be injected. Thus, a high-quality thin battery is provided.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment will be described below with reference to FIGS. 1 (a) and 1 (b) and FIGS. 2 (a) and 2 (b).
[0029]
Example 1
1 (a) and 1 (b) are exploded perspective views schematically showing an embodiment of this embodiment. Prepare an exterior film body 5 longer than the required dimensions with both ends open, and lead out and seal the electrode terminals 6a and 6b of the battery element 6 on one end side, and attach the battery element 6 in the exterior film body 5 Deploy. Next, on the other end opening side of the exterior film body 5, a region (part) adjacent to the mounted / arranged battery element 6 is welded leaving a part, and the battery element 6 is temporarily placed in the exterior film body 5. A structure 7 as shown in FIG.
[0030]
Here, the exterior film body 5 is made of, for example, a polyethylene terephthalate resin layer on both surfaces (both main surfaces) of an aluminum foil, and a heat-fusible resin layer (for example, polypropylene) on one surface of the polyethylene terephthalate resin layer. It is made of a laminate film provided with a (resin layer). Then, the exterior film body 5 is laminated so that the heat-fusible resin layers face each other and the battery element 6 is sandwiched therebetween, and one end portion that forms an electrolyte inlet is opened 5a, and the opening 5a side is formed. A part of the region adjacent to the battery element 6 and the other edge portion 5b are sealed by heat sealing.
[0031]
The battery element 6 is electrically connected to the sheet-like positive electrode and the sheet-like negative electrode, the sheet-like electrolyte system interposed and disposed between the electrodes, and both the sheet-like electrodes, respectively. The corresponding electrode terminals 6a and 6b are hermetically sealed and extended (derived) from the exterior film body 3 apart from the current collector sheet in contact with the sheet-like positive and negative current collectors.
[0032]
Thereafter, as shown in FIG. 1 (b), the structure 7 is mounted on the corresponding carrier jig 8 with the opening 5a side of the exterior film body 5 facing upward, and the required electrolyte is repeatedly or intermittently applied. It arrange | positions facing the discharge outlet 9a of the metering pump 9 to discharge / inject. In this state, the electrolyte solution is injected and filled into the battery element 6 housed in the structure 7 by the metering pump 9.
[0033]
After injecting and filling the fixed amount of the electrolytic solution, the structure 7 is mounted on the carrier jig 8 and transferred to a vacuum chamber that is switchably connected to a vacuum exhaust system (not shown), and the vacuum chamber is exhausted. Then, the battery element 6 is impregnated with the electrolyte under filling and filling under reduced pressure.
[0034]
That is, a predetermined amount of electrolytic solution is discharged and injected from the discharge port 9a of the metering pump 9 into the opening 5a of the exterior film body 5 in which the battery element 6 is incorporated and mounted in the semi-welded and sealed type at one end side. Thereafter, after injecting and filling the electrolytic solution into the battery element 6, the structure 7 attached to the carrier jig 8 is placed in a vacuum chamber in a normal pressure state. Next, the evacuation system is driven to depressurize and evacuate the structure 7 mounted in the vacuum chamber and the carrier jig 8 in a normal pressure state. Then, the vacuum chamber is maintained in a state where a certain reduced pressure (for example, a degree of vacuum of about 2 torr) is reached, and the battery element 6 is impregnated with the injected and filled electrolyte.
[0035]
As described above, since the normal pressure is switched to the reduced pressure state after the electrolyte solution is injected and injected, bubbles remaining in the structure 7, particularly, the battery element are removed. On the other hand, the electrolyte of the vacuum impregnation is completed and the vacuum chamber 11 is switched to a normal pressure, so that amount, the pressure is that pressure Waru, the I defoaming properties coupled with respect to the cell element The electrolytic solution is impregnated densely.
[0036]
In this way, after injecting and impregnating a predetermined amount of the electrolyte, the non-welded portion adjacent to the built-in / mounted battery element 6, in other words, on the opening 5 a side of the fusion-bonded film body 5, As the electrolyte injection port, a part is left without being welded, and the part is sealed by thermal welding. Thereafter, a thin battery having a predetermined size, shape, or standard is obtained by cutting and separating while leaving the region of the exterior film body 6 in which the region adjacent to the battery element 6 is hermetically sealed by heat welding. .
[0037]
Example 2
2 (a) and 2 (b) are exploded perspective views schematically showing an embodiment of this embodiment.
First, a sheet-like assembly 12 of a thin battery as shown in perspective in FIG. That is, two exterior films 5 'longer than the required dimensions are prepared, and regions corresponding to the electrode terminals 6a and 6b led out to one end side are opened 5b, and a plurality of exterior films 5' are provided between the two exterior films 5 '. The battery elements 6 are arranged and sandwiched in an aligned manner, and the surface of the exterior film 5 ′ that is partitioned and opposed to each battery element 6 is thermally welded to produce a sheet-like assembly 10 in which the battery elements 6 are incorporated and mounted. did.
[0038]
Here, the section for each battery element 6 in the sheet-like assembly 10 includes the lead-out side of the electrode terminals 6a, 6b, the peripheral part including the other side 5c adjacent to the battery element 6, and the lead-out of the electrode terminals 6a, 6b. The exterior film 5 'surfaces are heat-welded to each other, leaving a part of the side (region) 5d adjacent to the battery element 6 on the side opposite to the side. Further, a part formed by the tip side 5e facing the side 5d, which is partly non-thermally welded, is cut in part 5f to serve as an electrolyte injection port.
[0039]
Furthermore, the exterior film body 5 ′ is formed by, for example, a polyethylene terephthalate resin layer on both surfaces (both main surfaces) of an aluminum foil, and a heat-fusible resin layer (for example, polypropylene) on one surface of the polyethylene terephthalate resin layer. It is made of a laminate film provided with a (resin layer).
[0040]
Next, the sheet-like assembly 10 is placed and fixed on the flat surface of the carrier jig 8 'with a flat surface with the electrolyte injection port 5f facing upward on the flat surface of the carrier jig 8' with a flat surface. Set in the vacuum chamber 11. Here, the vacuum chamber 11 includes a metering pump 9 capable of metering out the electrolyte solution and a vacuum exhaust system 12 capable of switching to normal pressure.
[0041]
In the case of this embodiment, the electrolyte metering pump 9 or the electrolyte discharge port 9a is opened in the exterior film '(electrolyte injection port) for each of the battery elements 6 that are partitioned and installed in the vacuum chamber 11. ) It is arranged corresponding to 5f. In this case, the electrolyte metering pump 9 or the electrolyte discharge port 9a can be moved, or the carrier jig 8 'with a flat surface can be moved to the X and Y directions, so that one electrolyte metering pump 9 can be used. Or it can also be set as the electrolyte solution discharge port 9a.
[0042]
Then, in accordance with the case of Example 1, required electrolyte injection (filling), decompression impregnation procedure or operation, part of the electrolytic solution injection port for the battery element 6 is left unwelded. Heat welding / sealing, cutting and separating in a state where the region of the exterior film body 5 'in which the region adjacent to the battery element 6 is hermetically sealed by heat welding is left, so that a predetermined dimension / shape or standard is thin A battery is obtained.
[0043]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, the constituent material of the exterior film body or the exterior film may be changed to another material, and the exterior film body or the exterior film may be heat-sealed or bonded by folding the exterior film in the battery element assembling process. You may form by the adhesive effect | action etc. of an agent.
[0044]
【The invention's effect】
According to the first to fifth aspects of the invention, since a certain amount of electrolyte can be injected and impregnated with high accuracy, a high-quality thin battery can be provided with high yield. That is, since the exterior film body is set to be long and a part of the electrolyte is used as a primary reservoir or a funnel for pouring / filling, and the action of pressure reduction / pressurization is added and impregnated / filled, A certain amount of electrolyte is reliably injected and filled. In addition, in the step of injecting and filling the electrolytic solution, for example, operations such as attachment and detachment of the injection funnel are omitted, and there is no waste or leakage of the electrolytic solution. Therefore, it greatly contributes to the provision of a high-quality thin battery with low cost and high yield.
[0045]
In particular, in the invention of claim 2, since the electrolytic solution can be filled and impregnated into a large number of battery elements at the same time, productivity can be improved.
[Brief description of the drawings]
1A and 1B schematically show a first embodiment, in which FIG. 1A is a perspective view showing a state in which a battery element is built in and attached to an exterior film body, and FIG. 1B is a perspective view showing an electrolyte injection state; Figure.
FIG. 2 schematically shows a second embodiment, in which (a) is a perspective view showing a sheet-like assembly in which a plurality of battery elements are incorporated and mounted in an exterior film body, and (b) is an electrolytic solution. The perspective view which shows the injection | pouring state.
FIG. 3 is a cross-sectional view showing a main configuration of a polymer battery.
FIG. 4 is a perspective view schematically showing a state of a filling / impregnation operation of an electrolytic solution for an electrode element for a conventional thin battery.
[Explanation of symbols]
5,5 '…… Exterior film
5a …… Opening (electrolyte inlet)
5b …… Terminal opening
5c …… Both sides
5d …… Side part that is not welded
5e …… Tip edge
5f …… Incision (electrolyte inlet)
6 …… Battery element
6a, 6b ... Electrode terminal 7 ... Structure (one battery element built-in type)
8, 8 '... Carrier jig 9 ... Metering pump
9a …… Discharge port
10 …… Sheet assembly (multiple battery element built-in type)
11 …… Vacuum (decompression) chamber
12 …… Evacuation system (vacuum pump)

Claims (5)

A battery element is mounted and incorporated in the exterior film body that is open with one end side set larger than the required shape and dimensions, and the electrode terminal of the battery element is led to the other end side of the exterior film body to Sealing the other end side ;
A step of welding sealing while leaving a portion of the region where the opening portion side of the outer film body, adjacent the leading Symbol built-mounted and battery elements,
The step of injecting the electrolytic solution in the normal pressure state via the metering pump to the battery element side with the opening on the front end side of the exterior film body as the electrolytic solution injection port;
A step in which the space in which the exterior film body into which the electrolyte is injected is installed is changed from a normal pressure state to a reduced pressure state, and the battery element is impregnated with the electrolyte solution ;
The space in which the exterior film body in which the battery element impregnated with the electrolytic solution is mounted / built in is changed from the reduced pressure state to the normal pressure state, and the non-welded sealing portion remaining in the region adjacent to the battery element is welded and sealed. A method of manufacturing a thin battery.   2. The method of manufacturing a thin battery according to claim 1, wherein a plurality of battery elements are built in and attached to the exterior film body and separated from each other after welding sealing.   3. The method of manufacturing a thin battery according to claim 1, wherein the opening on the front end side of the exterior film body for injecting the electrolyte into the battery element is processed into a funnel shape. The method of manufacturing a thin battery according to any one of claims 1 to 3, wherein the exterior film body is a laminate film in which resin layers are provided on both surfaces of a metal layer. The method for manufacturing a thin battery according to any one of claims 1 to 4, wherein a heat-sealing resin layer is provided in a sealed region of the exterior film body.

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