JPH10270072A - Manufacture of nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a nonaqueous electrolyte secondary battery for easily carrying the batteries on a manufacturing line by storing a number of generating elements between continuously long aluminum laminate sheets to do sealing wok and filing, preliminarily charging and evacuating work for nonaqueous electrolyte in sequence. SOLUTION: Generating elements 1 are stored at preset spaces between two long aluminum laminate sheets 2, 4 lapping each other and the aluminum laminate sheets 2, 4 around the generating elements 1, except in non-sealed paths 5, are heated and forced for sealing. Recesses 2a in which the generating elements 1 are stored are depressuried to fill nonaqueous electrolyte 9 and preliminarily change the generating elements 1. The recesses 2a in which the generating elements 1 are stored are depressurized again to fill the shortage of the nonqueous electrolyte 9 and heat and force the aluminum laminate sheets 2, 4 lapping each other in the non-sealed paths 5 for sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a nonaqueous electrolyte secondary battery in which a power generation element is covered with a sheet and hermetically sealed.

[0002]

2. Description of the Related Art In a non-aqueous electrolyte secondary battery, a power generation element (battery element) is covered with an aluminum laminate sheet by projecting only the tips of leads connected to the positive and negative electrodes of the power generation element. Some are filled with water electrolyte and sealed. For example, in a card type secondary battery, a non-aqueous electrolyte secondary battery sealed with such an aluminum laminate sheet is housed in a card type outer case. Unlike the aqueous electrolyte secondary battery, the nonaqueous electrolyte secondary battery generates almost no gas from the power generation element during charging, and thus can be hermetically sealed with such an aluminum laminate sheet.

[0003] In the conventional non-aqueous electrolyte secondary battery sealed with an aluminum laminate sheet, a bag of an aluminum laminate sheet is formed for each battery, and a power generation element is accommodated in the bag and the non-aqueous electrolyte battery is stored. It has been manufactured by filling the bag with a liquid and closing the opening of the bag with the leading end of the lead protruding.

[0004]

However, in some non-aqueous electrolyte secondary batteries, gas is generated from between the plates of the power generating element by a film forming reaction of the negative electrode only at the time of first charging. It is necessary to completely close the opening of the bag of the aluminum laminated sheet after precharging after injecting the non-aqueous electrolyte to complete gas generation.
In addition, if the power generating element contains air inside, even if a non-aqueous electrolyte is injected, the space between the electrodes will not be sufficiently filled, or if the gas generated during pre-charging is at atmospheric pressure, the electrode of the power generating element will not be filled. Because it is not enough to get out of between,
It is preferable to depressurize the inside of the bag of the aluminum laminate sheet by evacuation.

However, in the above-mentioned conventional manufacturing method, the aluminum laminate sheet containing the power generating element is transported one by one, the non-aqueous electrolyte is injected with the opening facing upward, and the preliminary charging and evacuation are performed. After that, the operation of closing the opening must be performed. For this reason, the conventional method of manufacturing a nonaqueous electrolyte secondary battery has a problem in that the configuration of the transport section and the like in the manufacturing line is complicated, and the cost of the equipment becomes too high.

The present invention has been made in view of the above circumstances, and accommodates a large number of power generating elements at predetermined intervals while superposing continuous long sheets, and sequentially seals or injects a non-aqueous electrolyte. It is an object of the present invention to provide a method for manufacturing a non-aqueous electrolyte secondary battery in which a battery is easily transported on a manufacturing line by performing operations such as preliminary charging and vacuuming.

[0007]

In order to solve the above-mentioned problems, a method for manufacturing a non-aqueous electrolyte secondary battery according to the present invention is performed while two long sheets are stacked, or
A step of storing the power generating elements at a predetermined interval while one side of one long sheet is folded back and superimposed, and a step of storing the power generating elements around the storage section of each power generating element in the superimposed sheet. A step of sealing together with all or a part of the leads of the power generating element sandwiched between these sheets, except for an appropriate unsealed path from the section to the side of the sheet, and each power generating element between the sealed sheets. A step of evacuating and depressurizing the inside of the storage section through the unsealed path, a step of injecting the nonaqueous electrolyte through the unsealed path into the storage section of each decompressed power generating element, and a step of filling the storage section with the nonaqueous electrolyte. Pre-charging the power generating element through a lead of the power generating element;
The method further comprises a step of evacuating the inside of the storage portion of each of the pre-charged power generating elements again through an unsealed path to reduce the pressure, and a step of sealing the overlapping sheets in the unsealed path.

According to the means, since a large number of power generating elements are sandwiched between two long sheets or while one long sheet is folded, the sheets are sealed. Just send it, vacuum the inside of the storage section of each power generation element,
Operations such as injecting a non-aqueous electrolyte into the storage portion and precharging each power generation element can be performed continuously.

The unsealed path is formed, for example, by forming a groove on the press surface of a heated mold so that the sheet is not heat-welded only at the groove, or by using a material such as fluororesin. A pipe or thin plate made of a heat-resistant resin that is difficult to adhere is inserted between the sheets, and even if this sheet is heated and pressed, it can be formed so as not to be welded at the inserted portion of the pipe or the thin plate. it can.

In the step of evacuating and decompressing the inside of the storage section of each power generation element through an unsealed path, the periphery of the storage section of each power generation element in the sealed sheet is covered with a chamber or the like, and the inside of the chamber or the like is evacuated. By pulling, it is preferable to reduce the pressure not only in the storage section but also around the storage section.

Further, in the step of pre-charging each power generation element, if the leads of this power generation element protrude from between the sealed sheets or if they are not exposed from the opening window of this sheet, a part of this sheet is peeled off. It is necessary to turn over before connecting to the charger.

In the method of manufacturing a non-aqueous electrolyte secondary battery according to a second aspect, before the step of sealing the overlapping sheets in the unsealed path, the unsealed portions are not sealed in the storage portions of the respective power generating elements which have been depressurized again by evacuation. A step of injecting a shortage of the nonaqueous electrolyte through the passage is inserted.

According to the means, the non-aqueous electrolyte which has become insufficient due to the preliminary charging can be replenished.

According to a third aspect of the present invention, there is provided a method for manufacturing a non-aqueous electrolyte secondary battery, comprising: a conduit for injecting a non-aqueous electrolyte through an unsealed passage into the housing of the power generating element; And a separate line is used for the pipe line for evacuation.

According to the means, when the pipe for injecting the non-aqueous electrolyte and the pipe for evacuation are used in common, salt is prevented from depositing and adhering from the non-aqueous electrolyte to block the pipe. be able to.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a front view showing a battery manufacturing process.
FIG. 4 is a perspective view showing details of a power generation element housing step in a battery manufacturing process.

In this embodiment, a method of manufacturing a non-aqueous electrolyte secondary battery in which a power generation element is covered with two aluminum laminate sheets and hermetically sealed will be described. The power generating element 1 shown in FIG.
In the same manner as in a normal winding type, the positive and negative electrodes and the separator are wound into a cylindrical shape, and two leads 1a connected to the positive and negative electrodes are projected from one end face of the cylindrical shape.
However, the power generating element 1 is flattened by crushing a cylindrical side surface. In addition, the power generating element 1 is not limited to a flat type obtained by crushing such a wound type.
A laminated type or any other configuration may be used. The power generating element 1 is not limited to one unit cell, but may be a plurality of assembled cells. Further, the number of leads 1a is not limited to two, and any number of leads can be projected.

The lower aluminum laminated sheet 2 is drawn out from a roll or the like (not shown) on the left side in the figure and supplied sequentially while it is long. First, the concave portions 2a are press-formed at predetermined intervals, and each of these concave portions is formed. Each of the power generating elements 1 is placed on 2a, and the upper aluminum laminate sheet 4 drawn from another roll 3 is overlaid thereon (power generating element storage step). At this time, each power generating element 1 has two leads 1
The leading end of “a” protrudes from the front side of the aluminum laminate sheets 2 and 4 and is placed.

Next, as shown in FIG. 1, the aluminum laminated sheets 2 and 4 (areas indicated by hatching A) that overlap each other around the power generating element 1 are heated and compressed by pressing from above and below with a high-temperature mold. And sealing (first sealing step). Here, the aluminum laminate sheets 2 and 4 are formed on a surface of a PET (polyethylene terephthalate) film which is a surface protective layer, on an opposing surface, by an aluminum film which is a barrier layer and a polyethylene film or polypropylene film which is a moisture barrier layer. It is a sheet on which a film or the like is laminated. Then, by laminating these aluminum laminated sheets 2 and 4 and pressing them under heat, the moisture barrier layers can be thermally welded to each other and sealed. In addition, the lead 1a of each power generating element 1 is previously covered with a film of eval resin serving as an electrolyte barrier layer via a bonding layer with a metal in the vicinity of the base. Therefore, when the aluminum laminate sheets 2 and 4 are overlapped with the leads 1a and heated and pressed, the moisture barrier layer and the electrolyte barrier layer are thermally welded to each other, and the gap between the aluminum laminate sheets 2 and 4 and the leads 1a is securely formed. Can be sealed.

However, in the first sealing step, as indicated by hatching A, the aluminum laminate sheets 2 and 4 of the unsealed path 5 extending from the concave portion 2a accommodating the power generating element 1 to the upper side in FIG. Do not allow this recess 2
The inside of a is communicated with the outside. Such an unsealed route 5
In order to form the groove, a groove may be formed on the press surface of both the upper and lower molds or any one of the molds so that only the portion to be the unsealed path 5 is not heated and pressed. Also, for example, even if a heat-pressing member is inserted between the aluminum laminated sheets 2 and 4 after inserting a welding prevention member such as a pipe or a thin plate made of a resin or the like having heat resistance such as fluororesin or polyimide which is difficult to adhere to, etc. Good. When the pipe is inserted between the aluminum laminated sheets 2 and 4, this pipe is once crushed by the pressing of the mold, but the heat welding between the aluminum laminated sheets 2 and 4 is prevented. If the inner hole of the pipe is widened, an unsealed path 5 is formed. Even when the welding prevention member is inserted between the aluminum laminated sheets 2 and 4, the heat welding of the insertion portion is similarly prevented, and the trace of pulling out the welding prevention member becomes the unsealed path 5.

When the first sealing step is completed, the aluminum laminate sheets 2 and 4 around the sealed recess 2a are housed in the chamber 6 (first reduced pressure injection step). Chamber 6
Is a structure in which the aluminum laminate sheets 2 and 4 are sandwiched on the lower chamber main body, and the inside is sealed by covering the lid from above. At this time, positioning holes are appropriately formed in the aluminum laminate sheets 2 and 4 at a predetermined pitch, and accurate positioning can be performed by the positioning pins in the chamber 6. A vacuum pump 8 for evacuating the chamber 6 is connected to the chamber 6 via a cold trap 7. The cold trap 7 is for removing the non-aqueous electrolyte mixed during the degassing to protect the vacuum pump 8. A nonaqueous electrolytic solution 9 is supplied to the chamber
There is provided a non-aqueous electrolyte injection device for injecting liquid from the front end of the zero. By the way, if the unsealed path 5 in the chamber 6 is not simply opened by simply heat-welding the aluminum laminate sheets 2 and 4, it must be opened by an appropriate means. For example, if the opening head is vacuum-sucked from below to the aluminum laminated sheet 4 below the unsealed path 5 and the opening head is pressed down, only the aluminum laminated sheet 4 is bent to open the unsealed path 5. it can.

In the chamber 6, a vacuum pump 8 can be connected via a cold trap 7 to a nozzle 10 for injecting a non-aqueous electrolyte 9. In this case, by switching the valve, the evacuation of the chamber 6 and the injection of the non-aqueous electrolyte 9 are performed through the same nozzle 10. However, after injection of the non-aqueous electrolyte 9, the nozzle 10
When vacuuming is performed with the droplets of the non-aqueous electrolyte 9 adhered to the solvent, the solvent volatilizes and the salt adheres to the inside of the tube, and during this repetition, the precipitated salt solidifies and blocks the conduit. There is a fear. Therefore, it is preferable to provide a pipeline for performing vacuum evacuation in the chamber 6 separately from the nozzle 10 as in the present embodiment.

In the first reduced pressure injection step, when the chamber 6 is sealed, the vacuum pump 8 is first operated to evacuate the chamber 6 to reduce the pressure. At this time, the pressure inside the concave portion 2a is also reduced through the unsealed path 5, and the air contained in the power generating element 1 is drawn out. Next, the tip of the nozzle 10 is inserted into the unsealed passage 5 by a nonaqueous electrolyte injection device, and a predetermined amount of the nonaqueous electrolyte 9 is injected into the concave portion 2a.
Then, the non-aqueous electrolytic solution 9 fills the depressurized concave portion 2a and quickly fills the inside of the power generating element 1.

The non-aqueous electrolyte 9 in the first vacuum injection step
Is completed, the chamber 6 is opened, the aluminum laminated sheets 2 and 4 are transferred, and the charger 11 is connected to the lead 1a protruding from the front side of the aluminum laminated sheets 2 and 4 to perform preliminary charging. Perform (preliminary charging step).
The charger 11 is provided with a connection terminal with a lead 1a on a belt conveyor transferred in synchronization with the aluminum laminated sheets 2 and 4, and charges the power generating element 1 with a constant voltage or a constant current through the lead 1a. Things. The pre-charging is the first charging performed after the injection of the non-aqueous electrolyte 9 in order to generate gas from between the electrodes of the power generating element 1, and it is sufficient to charge the battery to about 15% of the battery capacity.

When the pre-charging step is completed, the aluminum laminate sheets 2 and 4 are stored again in the chamber 6 (second pressure-reducing liquid injection step). The chamber 6 may have the same configuration as that used in the first reduced pressure injection step. Then, even when the chamber 6 is sealed in the second reduced pressure injection step, first, the vacuum pump 8 is evacuated. Then
The inside of the concave portion 2 a is depressurized through the unsealed path 5, and the gas is reliably extracted from between the electrodes of the power generating element 1. Next, the tip of the nozzle 10 is inserted into the unsealed passage 5 by a nonaqueous electrolyte injection device, and a predetermined amount of the nonaqueous electrolyte 9 is injected into the concave portion 2a. The injection of the nonaqueous electrolytic solution 9 is for replenishing the shortage by performing the pre-charging, and may be omitted if the replenishment of the shortage is unnecessary.

When the second vacuum injection step is completed, the chamber 6 is opened and the aluminum laminate sheets 2 and 4 are transferred to the vicinity of the unsealed path 5 (area indicated by hatching B).
Is heated and pressed by a high-temperature mold from above and below to seal (second sealing step). Then, the unsealed aluminum laminate sheets 2 and 4, which overlap with each other in the unsealed path 5, are welded and sealed, and the inside of the recess 2 a containing the power generation element 1 is completely sealed. A large number of batteries are formed on the laminated sheets 2 and 4 at predetermined intervals.

According to the method for manufacturing a non-aqueous electrolyte secondary battery of the present embodiment described above, a large number of power generating elements 1 are housed at a predetermined interval between the long aluminum laminated sheets 2 and 4 that overlap each other. Since the periphery of the concave portion 2a accommodating each power generating element 1 is sealed and the inside of the concave portion 2a is evacuated, or the non-aqueous electrolyte 9 is injected into the concave portion 2a to perform preliminary charging, a large number of batteries can be continuously connected. It can be manufactured and transported easily.

In the above embodiment, the case where the two aluminum laminated sheets 2 and 4 are overlapped and sealed is described. However, the other side of one wide aluminum laminated sheet 2 is folded back and overlapped. They can be matched. Further, in the above embodiment, the concave portion 2a for accommodating the power generation element 1 is formed in the lower aluminum laminate sheet 2, but the presence or absence of the formation of such a concave portion 2a is arbitrary.

Further, in the above embodiment, the aluminum laminated sheets 2 and 4 are used, but other types of laminated sheets or other resin sheets may be used as long as they have a barrier property. Further, in the above-described embodiment, the case where the aluminum laminated sheets 2 and 4 are heat-pressed and heat-welded is described. However, the means for sealing the sheets is not limited to such heat-sealing and is arbitrary.

Further, in the above embodiment, each power generating element 1
Of the lead 1a of the aluminum laminate sheet 2, 4
The lead 1a
May be completely covered with the aluminum laminate sheets 2 and 4 including the tip. In this case, when each lead 1a is completely covered and sealed, the charger 1 is connected to these leads 1a.
When connecting 1, the aluminum laminate sheets 2 and 4 need to be partially peeled off. However, if the aluminum laminated sheets 2 and 4 are provided with opening windows in advance to expose a part of the leads 1a, it is not necessary to peel off the aluminum laminated sheets 2 and 4 at the time of connection. The leads 1a are completely covered with the aluminum laminated sheets 2 and 4. However, if the vicinity of the tip of each of the leads 1a is not sealed by heat welding, the aluminum laminated sheets 2 and 4 are turned. The connection of the charger 11 can be performed only by the above.

[0032]

As is apparent from the above description, according to the method of manufacturing a non-aqueous electrolyte secondary battery of the present invention, a large number of power generating elements are stored at a predetermined interval between overlapping long sheets. It is possible to close the periphery of the storage section of each of these power generating elements, evacuate the storage section, or inject a non-aqueous electrolyte into the storage section to perform preliminary charging. The battery can be formed and transported continuously, and the productivity of the battery can be increased.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a front view illustrating a manufacturing process of a battery.

FIG. 2, showing an embodiment of the present invention, is a perspective view illustrating details of a power generation element housing process in a battery manufacturing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power generation element 1a Lead 2 Aluminum laminated sheet 4 Aluminum laminated sheet 5 Unsealed path 8 Vacuum pump 9 Non-aqueous electrolyte 11 Charger

Claims (3)

[Claims] 1. A power generation element is stored at a predetermined interval while two long sheets are overlapped or one long sheet is folded back and overlapped. And the surroundings of the storage section of each power generation element in the superposed sheets, except for an appropriate unsealed path from this storage section to the side of the sheet, of the power generation element sandwiched between these sheets. A step of sealing with all or a part of the leads; a step of evacuating and depressurizing the inside of the storage section of each power generating element between the sealed sheets through an unsealed path; A step of injecting the non-aqueous electrolyte, a step of pre-charging each power generation element filled with the non-aqueous electrolyte in the storage section through a lead of the power generation element, and a step of opening the inside of the storage section of each pre-charged power generation element through an unsealed path. True again Pulling and a step of depressurizing method of the nonaqueous electrolyte secondary battery characterized by comprising the step of sealing the sheets overlapping in the non-sealing path. 2. A step of injecting a shortage of the non-aqueous electrolyte through the unsealed passage into the storage section of each power generating element which has been depressurized again by evacuation before the step of sealing the sheets which overlap each other in the unsealed passage. The method for manufacturing a non-aqueous electrolyte secondary battery according to claim 1, wherein the battery is inserted. 3. A separate line for injecting the non-aqueous electrolyte into the housing of the power generating element through an unsealed channel, and a line for evacuating the housing of the power generating element through the unsealed channel. The method for producing a non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein: