JP5177989B2 - Manufacturing method of assembled battery and assembled battery - Google Patents

Description

  The present invention relates to an assembled battery manufacturing method and an assembled battery.

JP 2000-133220 A JP 2001-229924 A Table 98/042036

  In recent years, there has been a strong demand for reduction in size and weight of various electronic devices. To that end, improvement in the performance of secondary batteries, which are power sources, has been demanded, and various batteries have been developed and improved. Improvements in characteristics expected of batteries include higher voltage, higher energy density, higher load resistance, optional shape, and safety. Under such demand, lithium ion secondary batteries are secondary batteries that can achieve the highest voltage, high energy density, and high load resistance among the existing batteries, and improvements are actively promoted even now. ing.

  This lithium ion secondary battery generally includes a sheet-like positive electrode composed of a sheet-like positive electrode current collector and a positive electrode active material applied to the surface, a sheet-like negative electrode current collector, A sheet-like internal electrode pair formed by laminating a sheet-like negative electrode composed of a negative electrode active material applied on the surface via a separator, and this internal electrode pair is covered in a sealed state And a battery case containing an electrolytic solution therein, and a positive electrode terminal and a negative electrode terminal connected to each positive electrode and each negative electrode of the internal electrode pair in the battery case. Escapes as lithium ions from the positive electrode active material of the positive electrode into the negative electrode active material, enters the negative electrode active material of the negative electrode, and during discharge, the lithium ions that have entered the negative electrode active material are released into the electrolytic solution, and again And subjected to a charge and discharge by returning to the positive electrode active material in the electrode.

  In a lithium ion secondary battery currently in practical use, a composite oxide fine particle of lithium and cobalt, nickel or manganese is mixed with an electron conductor particle and a binder resin on the positive electrode, and applied to an aluminum current collector. In the negative electrode, a negative electrode containing a fine powder containing carbon atoms such as graphite, non-graphitizable carbon and coke is mixed with a binder resin and applied to a copper current collector. It has been. In addition, a separator in which a porous film such as polyethylene or polypropylene is filled with a non-aqueous solvent containing lithium ions is used. Such a lithium ion secondary battery is expected to be a large-capacity secondary battery used in the field of, for example, an electric vehicle because it can achieve a high energy density. Many developments and proposals have already been made. Has been done.

  For example, as the battery case, an inner surface layer made of a thermoplastic resin excellent in electrolytic solution resistance and heat sealability such as polyethylene and polypropylene on the inner surface side, and a metal excellent in flexibility and strength such as aluminum foil in the middle Forming a flexible bag-like envelope using a three-layer laminate film with a foil intermediate layer and an outer surface layer made of an insulating resin excellent in electrical insulation such as polyamide resin on the outer surface side In addition, a sheet-like lithium ion secondary battery that is formed by enclosing a sheet-like internal electrode pair and an electrolytic solution in the bag-like outer package and having a light weight, a thin shape, and flexibility has been proposed (for example, Patent Documents 1 to 3).

  This conventional sheet-like lithium ion secondary battery includes a pair of positive electrode terminals and a negative electrode terminal connected to each positive electrode and each negative electrode of the internal electrode pair inside the bag-shaped outer package, The pair of positive electrode terminals and negative electrode terminals penetrates the bag-like outer package in an airtight manner and protrudes to the outside, so that the battery output is taken out.

  However, each of the above prior arts has the following problems.

  For example, based on a request for increasing the capacity of a battery, sheet-like secondary batteries (hereinafter also referred to as secondary battery cells) disclosed in the above-described patent document are stacked in multiple layers, and an assembly of secondary battery cells ( (Hereinafter also referred to as an assembled battery), it becomes difficult to insert a welding jig or the like between electrodes facing each other in the stacking direction between the stacked sheet-like secondary battery cells. As a result, there is a problem that productivity is significantly impaired and productivity is lowered.

  In addition, based on recent demands for mounting and incorporating sheet-like secondary batteries in a wide variety of devices, the degree of freedom in design to cope with higher currents and higher voltages according to applications, or layout From this point of view, there is a growing demand for an increase in the degree of freedom of the sheet, and the features of the sheet-like secondary battery cell that are lightweight, thin, flexible, and can be reduced in size and weight are impaired. Therefore, it has been desired to realize an assembled battery that can be connected in parallel and / or in series at any location in the stacking direction.

  The present invention has been made in view of the above-described problems of the prior art, and the object of the present invention is to form an electrode terminal when forming a battery pack by stacking sheet-like secondary battery cells. An object of the present invention is to provide an assembled battery manufacturing method capable of improving connection workability and thereby improving productivity, and a sheet-like secondary battery cell used therefor.

  In order to achieve the above object, a method for manufacturing an assembled battery according to the present invention includes an internal electrode pair in which sheet-like electrode plates are stacked, an electrolytic solution, and a flexibility for accommodating the internal electrode pair and the electrolytic solution in a sealed state. A sheet-like secondary battery cell in which a positive electrode terminal and a negative electrode terminal connected to the internal electrode pair are formed so as to protrude outside the bag-like outer package. A method of manufacturing an assembled battery comprising: a stacking step of stacking a next sheet-like secondary battery cell on one sheet-like secondary battery cell; and a predetermined step of the one sheet-like secondary battery cell. A connecting step of connecting the electrode terminal to an electrode terminal facing the stacking direction of the next sheet-shaped secondary battery cell, and when the assembled battery is formed by sequentially repeating the stacking step and the connecting step, In the connecting step, the predetermined electrode of the one sheet-like secondary battery cell The sheet-shaped secondary battery cell is connected to the predetermined electrode terminal of the next sheet-shaped secondary battery cell so that the connected electrode terminal does not interfere with the connection work of the next connection process in the stacking direction. It is characterized by being bent toward the main body.

  Generally, when forming an assembled battery in a state where sheet-like secondary battery cells are laminated in multiple layers, there is not enough space to set a connection jig (for example, an ultrasonic welding jig) between the electrode terminals of the laminated cell pair. As a result, the electrode connection work becomes difficult and the productivity is remarkably reduced.

  Therefore, in the method for producing an assembled battery of the present invention, first, the next sheet-like secondary battery cell is laminated on one sheet-like secondary battery, and the corresponding predetermined electrode terminals are connected to each other in the lamination direction. After connecting the connected electrode terminals to the sheet-like secondary battery cell body side so that the connection jig and the connected electrode terminal do not interfere during the next connection work, the next sheet-like secondary battery cell is further Since the same connection work is performed by stacking, when the corresponding electrode terminals are stacked and connected, the previous electrode terminals are already bent toward the sheet-like secondary battery cell body side so as not to interfere with the connection jig. Therefore, a space for setting the connection jig in the stacking direction can always be secured, and connection workability and productivity can be improved.

  Each of the electrode terminals of the sheet-like secondary battery cell is provided with a notch extending in the protruding direction of the electrode terminal, and each of the electrode terminals is divided to provide a plurality of divided electrodes. In the one connecting step, a predetermined divided electrode of the plurality of divided electrodes of the one sheet-like secondary battery cell is replaced with a plurality of sheets of the next sheet-like secondary battery cell. While being connected to a predetermined divided electrode among the divided electrodes, the connected divided electrode is bent toward the sheet-shaped secondary battery cell main body side so as not to interfere with the connection work of the next connecting step in the stacking direction, The divided electrodes that are not involved in the connection in the next connection step may be similarly bent toward the sheet-like secondary battery cell main body side.

  In this case, by dividing the electrode terminal to form a divided electrode, the degree of freedom of connection of the electrode terminals between the sheet-like secondary battery cells is increased, and the parallel and / or at any point in the stacking direction. It is possible to connect in series, and at the same time, it is possible to always secure a space for setting the connection jig in the stacking direction, thereby improving the connection workability and productivity.

  Further, one divided electrode of at least one sheet-like secondary battery cell is connected to another sheet-like secondary battery cell laminated adjacent to the one sheet-like secondary battery cell, and The other divided electrode of the same polarity as the one divided electrode of the sheet-shaped secondary battery cell is opposite to the other sheet-shaped secondary battery cell in the stacking direction with the one sheet-shaped secondary battery cell interposed therebetween. Connected to another sheet-like secondary battery cell adjacent to the one sheet-like secondary battery cell, and the one divided electrode of the one sheet-like secondary battery cell and one divided electrode of different polarity Is connected to the other sheet-like secondary battery cell, and the one divided electrode of the one sheet-like secondary battery cell and another divided electrode having a different polarity are connected to the other sheet-like secondary battery cell. You may connect with.

  In this case, when connecting the divided electrode of one sheet-like secondary battery cell, the one divided electrode is further connected to another adjacent sheet-like secondary battery cell and has the same polarity. The other divided electrode is connected to another sheet-like secondary battery cell adjacent to the other sheet-like secondary battery cell via the one sheet-like secondary battery cell, and one divided electrode having a different polarity In addition to being connected to another adjacent sheet-like secondary battery cell, another divided electrode having a different polarity is adjacent to another sheet-like secondary battery cell via one sheet-like secondary battery cell. Therefore, any number of parallel connections at any location in the stacking direction can be performed without impairing workability during connection.

  Further, at least one divided electrode of at least one sheet-like secondary battery cell is connected to another sheet-like secondary battery cell laminated adjacent to the one sheet-like secondary battery cell, and The one sheet-like secondary battery on the opposite side in the stacking direction between the one sheet-shaped secondary electrode and the other sheet-like secondary battery cell. You may connect to another sheet-like secondary battery cell adjacent to a cell.

  In this case, when connecting the divided electrodes of one sheet-like secondary battery cell, at least one of the divided electrodes is further connected to another adjacent sheet-like secondary battery cell and different from each other. Since at least one polar split electrode is connected to another sheet-like secondary battery cell adjacent to another sheet-like secondary battery cell via one sheet-like secondary battery cell, workability at the time of connection Series connection at any point in the stacking direction is possible without impairing the above.

  The assembled battery according to the present invention includes an internal electrode pair in which sheet-shaped electrode plates are stacked, an electrolytic solution, and a flexible bag-like outer package that accommodates the internal electrode pair and the electrolytic solution in a sealed state. A battery assembly comprising a plurality of sheet-like secondary battery cells in which a positive electrode terminal and a negative electrode terminal connected to the internal electrode pair are formed in a protruding manner outside the bag-like outer package. Each of the positive electrode terminal and the negative electrode terminal is formed with a notch extending in the protruding direction of the electrode terminal, which divides the electrode terminal into a plurality of divided electrodes, and a plurality of stacked sheet-like two Among the secondary battery cells, one divided electrode of one sheet-like secondary battery cell is connected to another sheet-like secondary battery cell adjacent in the stacking direction, and the one sheet-like secondary battery The other split electrode of the same polarity as the one split electrode of the cell Another sheet-like secondary battery cell is connected to another sheet-like secondary battery cell adjacent to the one sheet-like secondary battery cell on the opposite side in the stacking direction across the one sheet-like secondary battery cell The sheet-shaped secondary battery cell body is bent toward the sheet-shaped secondary battery cell body side, or the other divided electrode is bent toward the sheet-shaped secondary battery cell body side.

  When configured in this manner, the external electrode terminal is divided into external electrode terminals that are formed to protrude outside the bag-like outer package of the sheet-like secondary battery cell to form divided electrodes. Since notches that can be bent in the stacking direction are provided, the degree of freedom of connection when connecting sheet-like secondary battery cells is increased, and parallel and / or series connection at any point in the stacking direction is possible. The sheet-like secondary battery cell which becomes can be realized.

  Here, the electrode terminals may be connected to each other by ultrasonic bonding and / or rivets.

  ADVANTAGE OF THE INVENTION According to this invention, when forming a assembled battery by laminating | stacking a sheet-like secondary battery cell, the manufacturing method of the assembled battery which can aim at the improvement of productivity by improving the connection workability | operativity of an electrode terminal by this. And the sheet-like secondary battery cell used for this can be implement | achieved cheaply by simple structure.

<First embodiment>

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a schematic view showing a configuration of the assembled battery according to the present invention, and FIG. 2 is a perspective view schematically showing an example of a sheet-like secondary battery cell. 3 is a left side view of the sheet-like secondary battery cell of FIG. 2, and FIG. 4 is a cross-sectional view taken along line AA of FIG. 2, and is an enlarged view of a portion surrounded by a circle A ′ in FIG. It is. Further, FIG. 5 is a schematic diagram for explaining the internal electrode pair.

  As shown in FIG. 1, the assembled battery 20 according to the present embodiment is configured by stacking and connecting (stacking and connecting) sheet-like lithium ion secondary batteries (sheet-like secondary battery cells) 10. Each sheet-like secondary battery cell 10 is formed by connecting the respective electrode terminals 3a (3b) in parallel and / or in series. In the present embodiment, the output external lead 50 (60) is connected to the electrode terminal 3a (3b) of the sheet-like secondary battery cell at the upper end and the sheet-like secondary battery cell at the lower end. The output of the assembled battery 20 is taken out from the external lead 50 (60).

  As shown in FIGS. 2 to 4, in the sheet-like secondary battery cell 10, the internal electrode pair 1 and the electrolytic solution 5 are accommodated in a sealed state by a flexible bag-like outer package 2. As shown in FIG. 4, the internal electrode pair 1 is formed in a sheet shape by alternately laminating sheet-like positive electrodes 1a and sheet-like negative electrodes 1b via separators 1c. A sheet-like electrode terminal (positive electrode terminal) 3a connected to each of the positive electrodes 1a in the pair 1 penetrates the heat seal portion 4 of the bag-like outer package 2 in an airtight manner and is fixed to the heat seal portion 4 so as to be heat sealed. It protrudes outside through the portion 4. The protruding portion is formed as a sheet-like external positive electrode terminal 35a. In other words, in the present embodiment, the positive electrode terminal 3 a includes the internal positive electrode terminal 30 a portion formed inside the bag-shaped outer package 2 and the external positive electrode terminal formed so as to protrude outside the bag-shaped outer package 2. 35a is comprised. Although not shown, the negative electrode terminal 3b is also connected to the negative electrode 1b, and the negative electrode terminal 3b is connected to the positive electrode with the bag-shaped outer package 2 interposed therebetween as shown in FIG. From the end opposite to the terminal 3a (in this example, the lower end in the figure), it penetrates the heat seal part 4 in the same manner as the positive electrode terminal 3a and protrudes to the outside in an airtight state. The external negative electrode terminal 35b is formed.

  In the present embodiment, as shown in FIG. 5, the internal electrode pair 1 has each positive electrode 1a formed by laminating positive electrode active materials 12 on both surfaces of an aluminum positive electrode current collector 11, Each negative electrode 1b is formed by laminating a negative electrode active material 14 on both surfaces of a negative electrode current collector 13 made of copper. The positive electrode terminal 3a (external positive electrode terminal 35a) is made of the same aluminum as the positive electrode current collector 11, and the negative electrode terminal 3b (external negative electrode terminal 35b) is made of the same copper as the negative electrode current collector 13. . However, the material is not particularly limited, and it is desirable to use an electrochemically stable metal material. Of these, preferable examples of the positive electrode terminal 3a (external positive electrode terminal 35a) include aluminum and aluminum alloys, and the negative electrode terminal 3b (external negative electrode terminal 35b) preferably includes copper, stainless steel, nickel, and the like. it can. For the positive electrode terminal 3a (external positive electrode terminal 35a), it is particularly preferable to use the same material as that for forming the positive electrode current collector, for example, aluminum, and for the negative electrode terminal 3b (external negative electrode terminal 35b). It is particularly preferable to use copper and / or nickel.

  In the present embodiment, the positive electrode terminal 3a (external positive electrode terminal 35a) and the negative electrode terminal 3b (external negative electrode terminal 35b) are both 100 μm in thickness and 30 mm in width. In the present invention, the thicknesses of the positive electrode terminal 3a (external positive electrode terminal 35a) and the negative electrode terminal 3b (external negative electrode terminal 35b) are, for example, about 50 μm or more, preferably 100 to 200 μm. Things can be used.

  In the present invention, the flexible bag-like outer package 2 that accommodates the internal electrode pair 1 and the electrolytic solution 5 in a sealed state therein has a strength that can be used as a battery case of the sheet-like secondary battery cell 10. If it has the outstanding electrolytic solution resistance with respect to the electrolytic solution 5 accommodated with it, it will not restrict | limit in particular, Specifically, for example, an electrolytic resistance, such as polyethylene, a polypropylene, a polyamide, an ionomer, is provided on the inner surface side. An inner layer made of a thermoplastic resin excellent in liquidity and heat sealability, an intermediate layer made of metal foil excellent in flexibility and strength such as aluminum foil and stainless steel foil in the middle, and an outer layer on the outer surface side such as A flexible bag-like outer package formed by using a laminate film having a three-layer structure having an outer surface layer made of an insulating resin excellent in electrical insulation such as a polyamide-based resin and a polyester-based resin (re-table 98 / It can be exemplified reference No. 42,036).

  In the present embodiment, the bag-like outer package 2 has an inner surface layer 2a made of polyethylene on the inner surface side, an intermediate layer 2b made of aluminum foil in the middle, and an outer surface layer 2c made of nylon on the outer surface side. It is made of a three-layer laminate film.

  As the separator 1c, any material such as a porous film, a nonwoven fabric, and a net can be used as long as it is electronically insulating and has sufficient strength against the adhesion between the positive electrode 1a and the negative electrode 1b. The material is not particularly limited, but a single layer porous film of polyethylene or polypropylene and a multilayered porous film of these are preferable from the viewpoint of adhesiveness and safety.

Moreover, as the solvent and the electrolyte salt used for the electrolytic solution 5 used as the ionic conductor, a non-aqueous solvent used in a conventional battery and an electrolyte salt containing lithium can be used. Specifically, as a solvent, an ester solvent such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate, a single solution of an ether solvent such as dimethoxyethane, diethoxyethane, diethyl ether, and dimethyl ether, and Two kinds of mixed liquids composed of the above-mentioned same-system solvents or different-system solvents can be used. The electrolyte salts are LiPF ₆ , LiAsF ₆ , LiClO ₄ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiN (C ₂ F ₅ SO ₂ ) _2. Etc. can be used.

  By the way, when a plurality of such sheet-like secondary battery cells 10 are laminated and the external battery terminals 35a (35b) of the laminated sheet-like secondary battery cells 10 are directly connected to form the assembled battery 20, When the electrode terminals 35a (35b) are connected, there is not enough space for setting a welding jig between the external electrode terminals 35a (35b), so that workability is significantly reduced.

  Therefore, in the assembled battery 20 according to the present embodiment, workability when connecting the external electrode terminals 35a (35b) is improved by sequentially stacking and connecting sheet-like secondary battery cells as follows. ing. Below, the manufacturing method of the assembled battery 20 which concerns on this Embodiment is demonstrated with reference to FIG. FIG. 6 is a diagram schematically showing a method for manufacturing the assembled battery 20 according to the present embodiment.

  First, a plurality of sheet-like secondary battery cells 10-1, 10-2,... As shown in FIG. Each of the sheet-like secondary battery cells 10-1, 10-2,... Has the same structure and is the same as the sheet-like secondary battery cell 10 described above, and thus detailed description thereof is omitted.

  Next, as shown in FIG. 6a, the output lead wire 50 is ultrasonically bonded to the tip of one of the external electrode terminals 35a and 35b (for example, the external positive electrode terminal 35a in this example).

  Here, the connection between the tip of the external positive electrode terminal 35a and the output lead wire 50 is not limited to ultrasonic bonding, and other connection methods (for example, mechanical bonding using rivets or the like) may be used. . However, it is preferable to use ultrasonic bonding from the viewpoint of enabling bonding of dissimilar metals and realizing good conductivity while eliminating the need for surface treatment such as removal of an oxide film or dirt on the metal surface. In addition, from the viewpoint of preventing the influence of heat and the like during ultrasonic bonding on the sheet-like secondary battery cell 10 main body, the bonding between the output lead wire 50 and the external positive electrode terminal 35a is performed with the external positive electrode. It is preferable to carry out at the tip of the electrode terminal 35a.

  After joining the output lead wire 50 to the external positive electrode terminal 35a, as shown in FIG. 6b, the output lead 50 that is not involved in the connection work (process) with the next sheet-like secondary battery cell 10-2 The joined external positive electrode terminal 35a is not interfered with the connection work with the next sheet-like secondary battery cell (when connecting the electrode terminal of the next sheet-like secondary battery cell, the connection jig is laminated. The external positive electrode terminal 35a is folded so as to be folded toward the main body side of the sheet-like secondary battery cell 10-1, and is insulated with an insulating tape. .

  Next, as shown in FIG. 6c, the polarities of the external electrode terminals 35a and 35b of the second sheet-shaped secondary battery cell 10-2 are reversed, and the first sheet-shaped secondary battery cell 10-1 A laminated cell pair is formed by laminating below, and the external negative electrode terminal 35b and the external positive electrode terminal 35a facing each other are ultrasonically bonded.

  Next, as shown in FIG. 6d, the external negative electrode terminal 35b of the first sheet-like secondary battery cell 10-1 joined and the external positive electrode terminal of the second sheet-like secondary battery cell 10-2. 35a is bent to the sheet-like secondary battery cell main body side to insulate.

  Next, as shown in FIG. 6e, the polarities of the external electrode terminals 35a and 35b of the third sheet-like secondary battery cell 10-3 are reversed so that the second sheet-like secondary battery cell 10-2 Laminate below to form the next stacked cell pair, ultrasonically bond the external positive electrode terminal 35b and the external negative electrode terminal 35a facing each other, and bend it to the sheet-like secondary battery cell body side for insulation treatment Apply.

  By repeating the procedure as described above, even when the sheet-like secondary battery cells 10-1, 10-2, ... are connected in multiple layers, the cells are sequentially stacked along the stacking direction (according to the stacking order). When connecting the electrode terminals between the sheet-like secondary battery cells constituting the pair, the previous electrode terminals have already been folded to the sheet-like secondary battery cell main body side so as not to interfere with the connection work. Therefore, a space for setting a welding jig or the like in the stacking direction can always be ensured, and workability can be improved.

In the present embodiment, when the joined electrode terminals 35a and 35b are bent, the electrode terminals 35a and 35b are folded from the base end portions from the viewpoint of reducing bending stress on the bag-like outer package 2. In order not to bend, it is preferable to use a jig or the like to bend in an R shape or multiple stages.
<Second Embodiment>

  Next, a second embodiment of the present invention will be described with reference to the drawings. In addition, the sheet-like secondary battery cell according to the present embodiment is connected to the external electrode terminals 35a and 35b of the sheet-like secondary battery cell 10 in the previous embodiment, respectively, in the protruding direction (extension direction) of the external electrode terminals. ) Are provided to form divided electrodes, which makes it possible to improve the connection workability when laminating sheet-like secondary battery cells in multiple layers, and in any parallel and / or series connection The members having the same functions as those of the previous embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 7, the sheet-like secondary battery cell 10 in the present embodiment is substantially U-shaped along the extending direction of the positive electrode terminal 3 a at the substantially central portion of each of the external electrode terminals 35 a and 35 b. Slits (notches) Ua, Ub are provided, and the divided electrodes 35a1, 35a2, 35b1, 35b2 that can be bent in the stacking direction are formed, and the other structures are the sheet-like secondary structure in the previous embodiment. It is the same as the battery 10.

  A method for manufacturing the assembled battery 20 according to the present embodiment will be described below with reference to FIGS. Specifically, using the four sheet-like secondary battery cells 10, the first sheet-like secondary battery cell 10-1 and the second sheet-like secondary battery cell 10-2 are connected in parallel. The third sheet-like secondary battery cell and the fourth sheet-like secondary battery cell are connected in parallel, and the second sheet-like secondary battery cell and the third sheet-like secondary battery cell A case where battery cells are connected in series will be described as an example.

  First, similar to the previous embodiment, a plurality of sheet-like secondary battery cells 10-1, 10-2,... Are prepared.

Next, as shown in FIG. 8a, in the extending direction of the electrode terminals 3a and 3b at the approximate center of the external electrode terminals 35a and 35b of the sheet-like secondary battery cells 10-1, 10-2. Slits Ua and Ub are formed, and divided electrodes 35a ₁ and 35a ₂ and 35b ₁ and 35b ₂ that can be bent in the stacking direction (vertical direction in this example) are formed in the external electrode terminal pairs 35a and 35b, respectively. To do.

Next, as shown in FIG. 8b, the output lead wire 50 is ultrasonically bonded to the tip of the divided electrode 35a1 of _one of the external electrode terminals 35a and 35b (for example, the external positive electrode terminal 35a in this example). .

After the output lead wire 50 is joined to the divided electrode 35a ₁ of the external positive electrode terminal 35a, as shown in FIG. 8c, the divided electrode 35a ₁ and the divided electrode 35a, which are not involved in the next connection operation (process). ₁ and the divided electrode 35b ₂ of the external negative electrode terminal 35b located diagonally across the sheet-shaped secondary battery cell 10-1 are folded so as to be folded toward the sheet-shaped secondary battery cell main body, and the folded portion 35a ₁ , 35b ₂ is insulated with an insulating tape. When the joined divided electrodes 35a ₁ and 35b ₂ are bent, they are bent in an R shape or in multiple stages using a jig or the like so as not to be bent from the base ends of the divided electrodes 35a ₁ and 35b _2. It is preferable.

Next, as shown in FIG. 9 a, the second sheet-like secondary battery cell 10-2 is matched with the polarities of the external lead portions 35 a, 35 b so that the first sheet-like secondary battery cell 10- A stacked cell pair is formed by stacking on 1. Then, the split electrode 35a ₂ of the first sheet-like secondary battery cell 10-1 (the split electrode of the secondary battery cell 10-1 adjacent to the split electrode 35a ₁ joined with the output lead wire 50), and the upper and lower sides The divided electrode 35a ₂ of the second sheet-shaped secondary battery cell 10-2 facing the direction is ultrasonically bonded and the divided electrode 35b _{1 of} the sheet-shaped secondary battery cell 10-1 positioned diagonally. And the divided electrode 35b _{1 of the} sheet-like secondary battery cell 10-2 are ultrasonically bonded in the same manner.

Thereafter, as shown in FIG. 9b, the ultrasonically bonded divided electrodes 35a ₂ -35a ₂ and 35b ₁ -35b ₁ are not interfered with the connection work with the next sheet-shaped secondary battery cell (the next sheet-shaped When connecting the split electrode of the secondary battery cell, set the connection jig in the stacking direction and sandwich the external electrode terminal), bend it to the sheet-like secondary battery cell body side, and insulate The sheet-like secondary battery cells 10-1 and 10-2 are directly connected in parallel by performing an insulation process with a tape. In addition, the divided electrode 35a ₁ of the second sheet-shaped secondary battery cell 10-2 is similarly bent to the sheet-shaped secondary battery cell main body side as a divided electrode that does not participate in the next connection work, and is subjected to insulation treatment. Apply.

Next, as shown in FIG. 10a, the third sheet-like secondary battery cell 10-3 is connected to the external electrode terminals 35a and 35b of the sheet-like secondary battery cells 10-1 and 10-2 previously laminated. The external electrode terminals 35a (35b) of the second sheet-like secondary battery cell and the external electrode terminals 35b (35a) of the third sheet-like secondary battery cell 10-3 are laminated so that the polarities are reversed. The third sheet-shaped secondary battery cell 10-3 is stacked on the second sheet-shaped secondary battery cell 10-2 to form the next stacked cell pair (facing each other in a direction facing each other). To do. Then, the second divided electrode 35b ₂ and the third divided electrode 35a ₂ are ultrasonically joined and connected in series.

Next, as shown in FIG. 10b, the bonding electrodes 35b ₂ -35a ₂ are bent toward the sheet-like secondary battery cell main body side to perform insulation treatment. Further, the third divided electrode 35b ₁ is subjected to an insulation treatment by being bent toward the sheet-like secondary battery cell main body side as a divided electrode not involved in the next connection work.

The sheet-type secondary battery cell 10-4 is a lowermost layer, as shown in FIG. 11a, after bonding the output lead 60 to the divided electrode 35b ₁ of the external negative electrode terminal 35b, and the divided electrode 35b ₁ Then, the divided electrode 35b ₁ and the divided electrode 35a ₂ of the external positive electrode terminal 35a located diagonally across the sheet-like secondary battery cell 10-4 are folded to the sheet-like secondary battery cell 10-4 main body side. The folded portions 35a ₁ and 35b ₂ are insulated with an insulating tape. Then, the fourth sheet-like secondary battery cell 10-4 is matched in polarity with the external electrode terminals 35a, 35b of the previously laminated sheet-like secondary battery cell 10-3 (third sheet-like secondary battery 10-3). The third sheet-like secondary electrode so that the external electrode terminal 35a (35b) of the secondary battery cell and the external electrode terminal 35a (35b) of the fourth sheet-like secondary battery cell 10-3 face each other. A fourth sheet-like secondary battery cell 10-3 is stacked on the battery cell 10-2. Thereafter, the three eyes 4 th divided electrodes 35a ₁ and between 35b ₂ together with ultrasonic bonding, by bending the joining portion in a sheet-type secondary cell main body side subjected to insulation processing (see FIG. 11b) .

  By the procedure as described above, an assembled battery in which the sheet-like secondary battery cells 10-1 to 10-4 are stacked in two parallel two series can be formed.

In the present embodiment, when the parallel connection is made, the divided electrodes (for example, the divided electrodes 35 a ₂ and the divided electrodes 35 b ₁ ) that are positioned diagonally across the sheet-like secondary battery cell are connected to each other. has been ultrasonically bonded, split electrodes are (e.g., the divided electrodes 35a ₂ to each other and the divided electrode 35b ₂ to each other) facing each other and a may be ultrasonically bonded.

  Moreover, in this Embodiment, although the case where the assembled battery 20 was comprised by laminating | stacking four sheet-like secondary battery cells 10-1 to 10-4 was illustrated, naturally sheet-like secondary battery cell 10 The number of stacked layers can be arbitrarily set, and parallel and / or series connection at any point in the stacking direction can be set.

That is, for example, sheet-like secondary battery cells having the same polarity are stacked, and at least one sheet-like secondary battery cell (in this example, 10-2, for example), one divided electrode (for example, divided electrode 35a) ₂ ) is connected to another sheet-like secondary battery cell (for example, 10-1) adjacent in the stacking direction, and another divided electrode (for example, 35a ₂ ) is connected to another sheet-like secondary battery cell (for example, 35a ₂ ). For example, it is connected to 10-3) and one divided electrode (for example, 35b ₁ ) of different polarity is connected to another sheet-like secondary battery cell (for example, 10-1) and another divided By connecting the electrode (for example, 35b ₂ ) to another sheet-like secondary battery cell (for example, 10-3), it is possible to connect in any number of stacked layers in any position in the stacking direction. In addition, the bus bar can be omitted in the parallel connection in the stacking direction.

In addition, for example, sheet-like secondary battery cells having reversed polarity are stacked, and at least one divided electrode (for example, divided) of at least one sheet-like secondary battery cell (for example, 10-3 in this example). The electrode 35a ₂ ) is connected to another sheet-like secondary battery cell (for example, 10-2) adjacent in the stacking direction, and at least one divided electrode (for example, 35b ₂ ) having a different polarity is connected to another adjacent By connecting to the sheet-like secondary battery cell (10-4), series connection at any point in the stacking direction becomes possible.

  In any case, when joining the divided electrodes of the sheet-shaped secondary battery cells, the divided electrodes of the already stacked sheet-shaped secondary battery cells that are not involved in the connection operation (process) are Since both are already folded to the sheet-like secondary battery cell main body side, the connecting jig is set in the stacking direction not only with ultrasonic bonding but also with other bonding means such as rivets, for example. Space can always be secured and connection workability and productivity can be improved.

It is a schematic diagram which shows the structure of the assembled battery which concerns on this invention. It is a perspective view which shows typically the sheet-like secondary battery cell which concerns on this invention. It is a left view of the sheet-like secondary battery cell of FIG. FIG. 3 is a cross-sectional view of the sheet-shaped secondary battery cell of FIG. 1 taken along line AA, and is an enlarged view of a portion surrounded by a circle A ′ in FIG. 2. It is a typical enlarged view for demonstrating the internal electrode pair in FIG. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 1st embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 1st embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 1st embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 1st embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 1st embodiment of this invention. It is a schematic diagram which shows the structure of the sheet-like secondary battery cell which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention. It is a schematic diagram for demonstrating the manufacturing method of the assembled battery which concerns on 2nd embodiment of this invention.

Explanation of symbols

1: internal electrode pair, 1a: positive electrode, 1b: negative electrode, 1c: separator, 2: bag-like envelope, 3a: positive electrode terminal, 3b: negative electrode terminal, 4: heat seal part, 5: electrolyte, 10: sheet-type secondary battery cells, 35a: external positive electrode terminal, 35b: external negative electrode terminal, 35a _1, 35a _2: positive divided electrodes, 35b _1, 35b _2: negative divided electrodes, 50 and 60: the output lead Line, B: Busbar, Ic ₁ , Id ₁ : Diagonal connection main current path, Ic ₂ , Id ₂ : Opposite connection main current path, Ua, Ub: Slit

Claims (6)

An internal electrode pair in which sheet-like electrode plates are stacked, an electrolytic solution, and a flexible bag-like outer package that accommodates the internal electrode pair and the electrolytic solution in a sealed state, and is connected to the internal electrode pair. A method for producing a battery pack , in which at least three or more sheet-like secondary battery cells, in which electrode terminals and negative electrode terminals protrude from the bag-like outer package, are sequentially connected,
A stacking step of stacking the next sheet-like secondary battery cell on one sheet-like secondary battery cell;
A connecting step of connecting a predetermined electrode terminal of the one sheet-like secondary battery cell to an electrode terminal facing the stacking direction of the next sheet-like secondary battery cell, the stacking step and the connecting step. When forming an assembled battery by repeating sequentially,
In one connection step, the predetermined electrode terminal of the one sheet-like secondary battery cell is connected to the predetermined electrode terminal of the next sheet-like secondary battery cell, and the connected electrode terminal is connected in the stacking direction. A method for producing an assembled battery, wherein the battery pack is bent toward the sheet-like secondary battery cell main body so as not to interfere with a connection operation in a subsequent connection step. Each of the electrode terminals of the sheet-like secondary battery cell is provided with a notch extending in the protruding direction of the electrode terminal, and each of the electrode terminals is divided to provide a plurality of divided electrodes, and the divided electrodes are stacked. Bendable in the direction,
In the one connection step, a predetermined divided electrode of the plurality of divided electrodes of the one sheet-shaped secondary battery cell is replaced with a predetermined divided electrode of the plurality of divided electrodes of the next sheet-shaped secondary battery cell. Connect and bend the connected divided electrodes to the sheet-like secondary battery cell body side so as not to interfere with the connection work of the next connection process in the stacking direction, and do not participate in the connection of the next connection process The method for manufacturing an assembled battery according to claim 1, wherein the divided electrodes are similarly bent toward the sheet-like secondary battery cell main body.   One divided electrode of at least one sheet-like secondary battery cell is connected to another sheet-like secondary battery cell stacked adjacent to the one sheet-like secondary battery cell, and the one sheet-like secondary battery cell is connected. The other divided electrode of the same polarity as the one divided electrode of the secondary battery cell is placed on the opposite side in the stacking direction with the one sheet-shaped secondary battery cell sandwiched with respect to the other sheet-shaped secondary battery cell. Connected to another sheet-like secondary battery cell adjacent to one sheet-like secondary battery cell, and the one divided electrode of the one sheet-like secondary battery cell and one divided electrode of different polarity, Connect to the other sheet-like secondary battery cell and connect the one divided electrode of the one sheet-like secondary battery cell and another divided electrode of a different polarity to the other sheet-like secondary battery cell The manufacturing method of the assembled battery of Claim 2 characterized by the above-mentioned.   At least one divided electrode of at least one sheet-like secondary battery cell is connected to another sheet-like secondary battery cell laminated adjacent to the one sheet-like secondary battery cell, and the one division Adjacent to the one sheet-like secondary battery cell on the opposite side in the stacking direction with the other sheet-like secondary battery cell and the one sheet-like secondary battery cell sandwiching at least one divided electrode having a different polarity from the electrode It connects to another sheet-like secondary battery cell which does, The manufacturing method of the assembled battery of Claim 2 characterized by the above-mentioned. An internal electrode pair in which sheet-like electrode plates are stacked, an electrolytic solution, and a flexible bag-like outer package that accommodates the internal electrode pair and the electrolytic solution in a sealed state, and is connected to the internal electrode pair. An assembled battery configured by sequentially stacking and connecting sheet-like secondary battery cells in which an electrode terminal and a negative electrode terminal are formed to protrude outside the bag-like outer package,
Each of the positive electrode terminal and the negative electrode terminal is formed with a notch extending in the protruding direction of the electrode terminal, which divides the electrode terminal into a plurality of divided electrodes,
Of the plurality of stacked sheet-like secondary battery cells, one divided electrode of one sheet-like secondary battery cell is connected to another sheet-like secondary battery cell adjacent in the stacking direction, The other divided electrode of the same polarity as the one divided electrode of the one sheet-like secondary battery cell is opposite to the stacking direction across the other sheet-like secondary battery cell and the one sheet-like secondary battery cell. It is connected to another sheet-like secondary battery cell adjacent to the one sheet-like secondary battery cell on the side and bent to the sheet-like secondary battery cell main body side, or the other divided electrode alone is a sheet A battery pack characterized by being bent toward the main body side of the secondary battery cell.   The assembled battery according to claim 5, wherein the electrode terminals are connected by ultrasonic bonding and / or rivets.

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