JP4496575B2 - Battery manufacturing method and battery manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery manufacturing method, and is particularly suitable for use in manufacturing a thin battery such as a polymer battery.
[0002]
[Prior art]
As a power source for portable electronic devices, a battery having a large capacity and a high output has been demanded along with a reduction in size, weight, and thickness. In order to meet such demands, in recent years, thin polymer batteries having a generally sheet shape as a whole have been developed.
[0003]
The element part of the polymer battery (hereinafter referred to as the battery element) is laminated and integrated by winding with a gel electrolyte layer and a separator interposed between a positive electrode and a negative electrode each having a strip shape (film shape). ing. A pair of electrode terminals (tabs) is led out from this battery element. Among these, one electrode terminal is a terminal (positive electrode terminal) corresponding to the positive electrode, and the other electrode terminal is a terminal (negative electrode terminal) corresponding to the negative electrode.
[0004]
The battery element with electrode terminals is sealed and packed after being stored in a housing recess of an exterior sheet formed corresponding to the element shape and element size.
[0005]
When manufacturing such a thin battery (polymer battery or the like), the assembled battery element 1 is set on the exterior sheet 2 as shown in FIG. In this setting, the pair of electrode terminals 3 </ b> A and 3 </ b> B protrude from the end of the battery element 1. On the other hand, a housing recess 4 is formed on the exterior sheet 2 by deep drawing. In addition, the pair of electrode terminals 3A and 3B are straightly led out from a substantially middle position in the thickness direction of the battery element 1 as shown in FIG. It is set substantially equal to the thickness of the element 1.
[0006]
Therefore, in the prior art, when the battery element 1 is set in the storage recess 4 of the exterior sheet 2, the battery element 1 is pushed in from the direction of the arrow as shown in FIG. The electrode terminals 3A and 3B are pressed against 4A and bent.
[0007]
[Problems to be solved by the invention]
However, in the above conventional method, the battery element 1 is forcibly pushed in while bending the electrode terminals 3A and 3B. Therefore, the bending state of the electrode terminals 3A and 3B depends on whether the element is pushed or not. It will change due to the deviation of the set position. As a result, as shown in FIGS. 10 (a) and 10 (b), the spacing P and the protrusion angle θ of the electrode terminals 3A and 3B vary, or the electrode terminal 3A as shown in FIGS. 11 (a) and 11 (b). , 3B, the protrusions S1 and S2 vary (S1> S2).
[0008]
In addition, an insulating member (resin piece or the like) that performs electrical insulation may be inserted into the base portion of the pair of electrode terminals 3A and 3B. When the battery element 1 is set in a state where the insulating member is actually inserted into the electrode terminals 3A and 3B, if the bending of each terminal is insufficient, as shown in FIG. The position shifts and becomes a factor of reducing the yield.
[0009]
Furthermore, when the pushing force of the battery element 1 against the exterior sheet 2 is insufficient, the battery element 1 is in a state where the electrode terminals 3A and 3B are hooked on the edge 4A of the housing recess 4 as shown in FIG. Will float. Therefore, it is necessary to push in the battery element 1 with a somewhat strong force, and this has become a bottleneck in stabilizing the bent shape of the electrode terminals 3A and 3B.
[0010]
[Means for Solving the Problems]
In the battery manufacturing method according to the present invention, a battery element having a substantially rectangular shape in plan view from which a pair of positive and negative electrode terminals is derived is set in a housing recess of an exterior sheet formed corresponding to the shape and size of the battery element. When sealing the battery element, the battery element is assembled, and a first step of connecting an electrode terminal to each of the positive electrode and the negative electrode of the battery element; A second step of pre-bending the sheet along the upper surface of the sheet; a third step of setting the battery element in the housing recess; and folding the exterior sheet so as to cover the battery element; And a fourth step of sealing the battery element. In the second step, the pair of electrode terminals such that a part of the pair of electrode terminals along the upper surface of the exterior sheet is flush with one main surface of the battery element. Is bent.
[0011]
In this battery manufacturing method, prior to setting the battery element with electrode terminals in the housing recess, the pair of electrode terminals are arranged along the side wall surface of the housing recess and the upper surface of the following exterior sheet. Since the battery element is bent in advance, the battery element is smoothly pushed in when the battery element is set thereafter, and the posture of the battery element and the bent shape of the electrode terminal in the set state are stabilized.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, the same components as those described in the above prior art will be described with the same reference numerals.
[0013]
FIG. 1 is a flowchart showing a battery manufacturing method according to an embodiment of the present invention. First, in step S1, the battery element is assembled. This battery element is assembled by winding a gel electrolyte layer and a separator between a positive electrode and a negative electrode each having a strip shape, thereby integrally stacking the positive electrode, the negative electrode, and the gel electrolyte layer. Is called.
[0014]
In the positive electrode, a positive electrode active material layer containing a positive electrode active material is formed on both surfaces of a positive electrode current collector. As the positive electrode active material, a composite oxide of lithium and a transition metal (for example, LiCoO ₂ , LiNiO ₂ LiMn ₂ O ₄ LiAlO _2, etc.) is used. As the positive electrode current collector, for example, a metal foil such as an aluminum foil is used.
[0015]
In the negative electrode, a negative electrode active material layer containing a negative electrode active material is formed on both surfaces of a negative electrode current collector. As the negative electrode active material, lithium metal, a lithium alloy, or a carbon material that can be doped / undoped with lithium (eg, graphite, non-graphitizable carbon, graphitizable carbon, etc.) is used. As the negative electrode current collector, for example, a metal foil such as a copper foil is used.
[0016]
The gel electrolyte contains a non-aqueous solvent, an electrolyte salt, and a matrix polymer. As the non-aqueous solvent, a known solvent (for example, ethylene carbonate, propylene carbonate, etc.) used as a non-aqueous solvent for the non-aqueous electrolyte is used. As the electrolyte salt, one that dissolves in the non-aqueous solvent is used. The matrix polymer gels a nonaqueous electrolytic solution in which the electrolyte salt is dissolved in the nonaqueous solvent. As such a matrix polymer, polyvinylidene fluoride, polyethylene oxide or the like is used.
[0017]
Moreover, in the assembly process of step S1, an electrode terminal is connected to each of the positive electrode and the negative electrode. As a material for the electrode terminal, for example, a metal such as copper, nickel, or aluminum is used. Moreover, spot welding, ultrasonic welding, etc. are used as a connection method of an electrode terminal.
[0018]
FIG. 2 is a perspective view of the assembled battery element. As shown in the figure, the battery element 1 has a substantially rectangular shape in plan view, and from one end thereof, an electrode terminal (positive electrode terminal) 3A corresponding to the positive electrode and an electrode terminal (negative electrode terminal) 3B corresponding to the negative electrode. Has been derived. The pair of electrode terminals 3 </ b> A and 3 </ b> B are connected (welded or the like) in a state in which the same amount protrudes in parallel (straight) from the end of the battery element 1.
[0019]
A resin insulating member 5 is attached to the pair of electrode terminals 3A and 3B in order to prevent an electrical short circuit. The insulating member 5 has two holes 5A and 5B corresponding to the respective electrode terminals 3A and 3B. By inserting the electrode terminals 3A and 3B into the holes 5A and 5B, the insulating member is provided at the base portion of each terminal. 5 is mounted.
[0020]
Subsequently, in step S2, the pair of electrode terminals 3A and 3B protruding from the battery element 1 as described above are bent (preformed) into a predetermined shape.
[0021]
FIGS. 3A and 3B show a configuration of a forming jig (terminal bending jig) suitable for bending electrode terminals. FIG. 3A is a plan view and FIG. 3B is a side view thereof. FIG. 4 is an enlarged view of a portion C in FIG. 3 and 4, the base plate 10 is a plate-like member having a rectangular shape in plan view, and support legs 11 using stud screws are provided at four corners on the lower surface side. On the other hand, a workpiece receiving mechanism 12 and a terminal bending tool mechanism 13 are mounted on the upper surface of the base plate 10.
[0022]
The work receiving mechanism 12 includes a work receiving base 15 fixed to the base plate 10 with four fixing screws 14, and a terminal guide 17 fixed to the work receiving base 15 with screws 16. A concave portion 15 </ b> A is formed on the upper surface of the work cradle 15, and the battery element 1 is positioned and held on the work cradle 15 by fitting and placing the battery element 1 in the concave portion 15 </ b> A.
[0023]
Further, an adjustment screw 18 is abutted against the end surface portion of the work cradle 15. The adjustment screw 18 is screwed to a support member 19 screwed onto the base plate 10. On the other hand, the hole of the work cradle 15 into which the fixing screw 14 is inserted is formed in a long hole shape. In such a configuration, the mounting position of the work cradle 15 in the left-right direction in FIG. 3 can be adjusted (finely adjusted) by abutting against the adjusting screw 18. Further, by tightening the nut 20 attached to the adjustment screw 18 in contact with the support member 19, the abutting position with the work cradle 15 can be fixed.
[0024]
The terminal bending tool mechanism 13 includes an inclined base 21 fixed on the base plate 10.
And a linear motion unit (LM guide) 22 mounted on the inclined surface 21A of the tilt base 21, a tool holding base 23 attached to the linear motion unit 22, and a tip of the tool holding base 23. The pair of bending tools 24A and 24B, and a tension spring 25 that pulls the bending tools 24A and 24B in one direction through the tool holding base 23 are provided.
[0025]
The linear motion unit 22 includes a fixed rail 22A that is screwed to the inclined surface 21A of the inclined base 21, and a slider 22B that is slidably engaged with the fixed rail 22A. A tool holder 23 is screwed to the upper surface. In addition, stopper pins 26A and 26B for restricting the movement range of the slider 22B are provided in the vicinity of both end positions of the fixed rail 22A.
[0026]
The bending tools 24 </ b> A and 24 </ b> B are each fixed to the tip of the tool holding base 23 with two screws 27. Here, as shown in FIG. 4, the inclination posture (inclination angle) α of the bending tools 24A and 24B by the inclined surface 21A of the inclination table 21 is the reference plane (battery element 1 is placed) of the work receiving base 15. Angle of 45 ° with respect to the surface). Further, in a state where the bending tools 24A and 24B are advanced to a predetermined bending execution position, between the front end surface of the bending tools 24A and 24B and the end position of the battery element 1, and the lower end surface of the bending tools 24A and 24B, A slight gap ΔG (for example, a gap corresponding to the thickness of the electrode terminal) is ensured between the upper end surface of the terminal guide 17. Furthermore, the lower end surfaces of the bending tools 24A and 24B are formed with a slight clearance angle β (for example, β≈3 °). Thereby, the front end surfaces of the bending tools 24A and 24B are arranged vertically along the end surface of the battery element 1, and the front end angle of the bending tools 24A and 24B (the angle formed between the tool front end surface and the tool lower end surface) is It is set at a substantially right angle (90 ° -β).
[0027]
On the other hand, an operation knob 28 for performing a terminal bending operation is provided at the rear end of the tool holding base 23. One end of the tension spring 25 is locked to the upper side surface of the inclined base 21, and the other end is locked to the side surface of the tool holding base 23. By the spring pressure action of the tension spring 25, the tool holding base 23 is urged so as to be always pulled back to the stopper pin 26B side together with the slider 22B. This urging direction is a direction in which the bending tools 24A and 24B are retracted (retracted) from the work cradle 15.
[0028]
Next, a procedure for bending the electrode terminals 3A and 3B using the forming jig having the above configuration will be described.
[0029]
First, the assembled battery element 1 with terminals is fitted into the recess 15 </ b> A of the work cradle 15 and placed. As a result, the pair of electrode terminals 3 </ b> A and 3 </ b> B protruding from the battery element 1 are arranged directly above the terminal guide 17. When the battery element 1 is set on the work cradle 15, the bending tools 24 </ b> A and 24 </ b> B are retracted from the work cradle 15 by the urging force of the tension spring 25.
[0030]
Next, while holding the battery element 1 with a fingertip or a holding jig (not shown), the operation knob 28 is held, and the slider 22B of the linear motion unit 22 is fixed to the fixed rail 22A against the urging force of the tension spring 25. Slide along. As a result, the tool holding base 23 moves integrally with the slider 22B, and the bending tools 24A and 24B move toward the work receiving base 15 accordingly.
[0031]
In the middle of this movement, the pair of bending tools 24A and 23B move closer to the surface on which the battery element 1 is placed with an inclination angle α as shown by an arrow in the drawing, as shown in FIG. , Abut against the corresponding electrode terminals 3A, 3B. Further, from this state, the bending tools 24A and 23B move while gradually bending the electrode terminals 3A and 3B, and finally, as shown in FIG. 4 and FIG. The movement of the tool stops as it advances to the corner formed by the end surface portion of the element 1 (or the end surface portion of the member 1 with the insulating member 5) and the upper surface portion of the terminal guide 17.
[0032]
As a result, as shown in FIG. 5C, the electrode terminals 3A and 3B protruding from the battery element 1 are bent into a substantially crank shape by the corresponding bending tools 24A and 24B. Since the electrode terminals 3A and 3B thus bent are originally made of a metal piece, the bent shape is maintained as it is even when the bending tools 24A and 24B are retracted as will be described later. The terminal bent shape (crank shape) at this time is along the side wall surface of the storage recess 4 to be described later and the upper surface of the exterior sheet 2 subsequent thereto.
[0033]
At the time of bending the terminals, rubbing between the two can be avoided by abutting the tip portions of the bending tools 24A and 24B against the electrode terminals 3A and 3B with an inclination angle α. Accordingly, the electrode terminals 3A and 3B can be reliably bent into a desired shape (a crank shape in the illustrated example) without being damaged. Further, since the electrode terminals 3A and 3B are bent so that the insulating member 5 is sandwiched between the battery element 1 and the insulating member 5 is not easily displaced.
[0034]
Thereafter, by releasing the operation knob 28, the slider 22B is pulled back along the fixed rail 22A by the urging force of the tension spring 25. As a result, the tip portions of the bending tools 24A, 24B are retracted from the work cradle 15, that is, returned to the original state. In this state, the battery element 1 that has been subjected to terminal bending is removed from the work cradle 15. Thereafter, according to the same procedure as described above, the terminal bending process of each battery element 1 is repeated. Thus, the electrode terminal bending step (step S2) is completed.
[0035]
Subsequently, in step S3, as shown in FIGS. 6 (a) and 6 (b), the battery element 1 with the terminal bent is set on the exterior sheet 2. As the exterior sheet 2, for example, a multilayer sheet having moisture resistance and insulation by sandwiching an aluminum foil between a pair of polyolefin films is used. A housing recess 4 is integrally formed in the exterior sheet 2 by deep drawing. The housing recess 4 is formed corresponding to the shape and size of the battery element 1. That is, the storage recess 4 is rectangular in plan view like the battery element 1, and the plane size (vertical and horizontal dimensions) is set slightly larger than that of the battery element 1. Further, the depth dimension of the storage recess 4 is set substantially equal to the thickness dimension of the battery element 1.
[0036]
As shown in FIG. 6 (a), the battery element 1 that has been bent is pushed in from the direction of the arrow into the storage recess 4 of the exterior sheet 2 formed in this manner in a state in which the battery element 1 has been folded upside down (inverted 180 °). . At this time, as described above, the pair of electrode terminals 3A and 3B are bent in advance in a crank shape in accordance with the shape of the housing recess 4, so that even if it is not forced with a strong force as in the conventional case, a very light force Thus, the battery element 1 can be smoothly set on the exterior sheet 2. Thereby, the attitude | position of the battery element 1 in a set state and the bending shape of electrode terminal 3A, 3B become stable.
[0037]
Thereafter, in step S4, after the exterior sheet 2 is folded back so as to cover the battery element 1, the peripheral edge of the sheet is sealed (welded, adhered, etc.), and the battery element 1 is hermetically packed with the exterior sheet 2.
[0038]
As described above, in the present embodiment, the electrode terminals 3A and 3B protruding from the battery element 1 are pre-bent (preformed), whereby the battery sheet 1 with the electrode terminals 3A and 3B and the exterior sheet 2 having the housing recess 4 are provided. Thus, the battery element 1 is set on the exterior sheet 2 in a state in which the shape difference in the combination part of both (1, 2) is eliminated.
[0039]
Therefore, even when the battery element 1 is set on the exterior sheet 2 in an unstable state such as manual work, the pair of electrode terminals 3A and 3B are connected to the upper end portions of the battery element 1 as shown in FIG. The distance P between the terminals can be kept constant. Moreover, as shown in FIG.7 (b), the floating of the battery element 1 etc. in the accommodation recessed part 4 can be eliminated, and the protrusion amount S of each electrode terminal 3A, 3B can be kept constant. Furthermore, when the insulating member 5 is attached to the electrode terminals 3A and 3B, the position of the insulating member 5 can be stabilized and the yield can be improved.
[0040]
【The invention's effect】
As described above, according to the battery manufacturing method of the present invention, prior to setting the battery element with electrode terminals in the housing recess of the exterior sheet, the pair of electrode terminals and the side wall surface of the housing recess are connected to this. Since the battery element is bent in advance along the upper surface of the exterior sheet that follows, the battery element is smoothly pushed in when the battery element is set thereafter, and the bent shape of the electrode terminal in the set state becomes stable. . As a result, the battery element can be stored in the exterior sheet in a stable posture at all times, and the yield is improved by suppressing the dimensional variations of the pair of electrode terminals (variations in terminal spacing, terminal protrusion angle, terminal protrusion amount, etc.). Can do.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a battery manufacturing method according to an embodiment of the present invention.
FIG. 2 is a perspective view of the assembled battery element.
FIG. 3 is a diagram illustrating a configuration of a forming jig (terminal bending jig) according to an embodiment of the present invention.
4 is an enlarged view of a portion C in FIG. 3. FIG.
FIG. 5 is a diagram illustrating a bending process of an electrode terminal according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a battery element setting step according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating a battery element set state according to an embodiment of the present invention.
FIG. 8 is a diagram (part 1) for explaining a conventional method;
FIG. 9 is a diagram (part 2) for explaining a conventional method;
FIG. 10 is a diagram (part 1) illustrating a conventional problem.
FIG. 11 is a diagram (part 2) for explaining a conventional problem;
FIG. 12 is a diagram (part 3) for explaining a conventional problem;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Battery element, 2 ... Exterior sheet | seat, 3A, 3B ... Electrode terminal (positive electrode terminal, negative electrode terminal), 4 ... Storage recessed part

Claims (3)

When the battery element having a substantially rectangular shape in plan view from which a pair of positive and negative electrode terminals is derived is set and sealed in an accommodation recess of an exterior sheet formed corresponding to the shape and size of the battery element,
A first step of assembling the battery element and connecting an electrode terminal to each of the positive electrode and the negative electrode of the battery element;
A second step of bending the pair of electrode terminals in advance so as to follow the side wall surface of the housing recess and the upper surface of the exterior sheet following the side surface;
A third step of setting the battery element in the storage recess;
After folding the exterior sheet so as to cover the battery element, in close contact with the outer instrumentation sheet periphery, it has a fourth step of sealing the battery element,
In the second step, the pair of electrode terminals are bent so that a part of the pair of electrode terminals along the upper surface of the exterior sheet is flush with one main surface of the battery element. A battery manufacturing method characterized by the above. The said 2nd process WHEREIN: An insulating member is mounted | worn with the base part of a pair of said electrode terminal, and the said pair of electrode terminal is bent so that the said insulating member may be pinched | interposed between the said battery elements. The method for producing a battery according to 1. The battery manufacturing method according to claim 1, wherein the battery manufacturing apparatus is used in the second step.
A workpiece cradle for positioning and holding a battery element to which a pair of electrode terminals are attached;
By moving closer to the surface of the work cradle on which the battery element is placed at a predetermined inclination angle, the work cradle abuts against the corresponding electrode terminal, and the tool front end surface follows the end face of the battery element. And a pair of bending tools in which an angle formed by the tool front end surface and the tool lower end surface is set at a substantially right angle.

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