JP6777202B2 - Manufacturing method of polygonal secondary battery - Google Patents

Description

The present invention relates to a method for manufacturing a rectangular secondary battery.

Square secondary batteries such as alkaline secondary batteries and non-aqueous electrolyte secondary batteries are used in driving power sources for electric vehicles (EVs) and hybrid electric vehicles (HEVs, PHEVs).

In these square secondary batteries, a battery case is formed by a bottomed tubular rectangular exterior body having an opening and a sealing plate that seals the opening. An electrode body composed of a positive electrode plate, a negative electrode plate, and a separator is housed in the battery case together with the electrolytic solution. A positive electrode terminal and a negative electrode terminal are attached to the sealing plate. The positive electrode terminal is electrically connected to the positive electrode plate via the positive electrode current collector, and the negative electrode terminal is electrically connected to the negative electrode plate via the negative electrode current collector.

The positive electrode plate includes a metal positive electrode core body and a positive electrode active material layer formed on the surface of the positive electrode core body. An exposed portion of the positive electrode core body from which the positive electrode active material layer is not formed is formed on a part of the positive electrode core body. Then, the positive electrode current collector is connected to the exposed portion of the positive electrode core. Further, the negative electrode plate includes a metal negative electrode core body and a negative electrode active material layer formed on the surface of the negative electrode core body. An exposed portion of the negative electrode core is formed in a part of the negative electrode core so that the negative electrode active material layer is not formed. Then, the negative electrode current collector is connected to the exposed portion of the negative electrode core.

For example, in Patent Document 1, a square rechargeable battery using a wound electrode body having a positive electrode core body exposed portion wound around one end and a negative electrode core body exposed portion wound around the other end. The next battery has been proposed. Further, Patent Document 2 proposes a square secondary battery using an electrode body in which a positive electrode core body exposed portion and a negative electrode core body exposed portion are provided at one end.

Japanese Unexamined Patent Publication No. 2009-032640 Japanese Unexamined Patent Publication No. 2008-226625

For in-vehicle secondary batteries, particularly secondary batteries used for EVs, PHEVs, etc., it is required to develop a secondary battery having a higher volumetric energy density and a larger battery capacity. In the case of the square secondary battery disclosed in Patent Document 1, the space on the left and right where the wound positive electrode core body exposed portion and the wound negative electrode core body exposed portion are arranged, and An upper space is required between the sealing plate and the wound electrode body, which causes difficulty in increasing the volumetric energy density of the secondary battery.

On the other hand, when an electrode body having a positive electrode core body exposed portion and a negative electrode core body exposed portion provided at one end thereof is used as in the square secondary battery disclosed in Patent Document 2, the volumetric energy density is increased. It becomes easy to obtain a square secondary battery with a high energy density. However, even if an electrode body having a positive electrode core body exposed portion and a negative electrode core body exposed portion provided at one end is used, the volumetric energy density is high in the conventional manufacturing method, particularly the conventional method of assembling the current collecting portion. It was difficult to manufacture a further improved square secondary battery.

An object of the present invention is to provide a polygonal secondary battery having a high volumetric energy density.

The method for manufacturing a homogeneous rectangular secondary battery of the present invention is as follows.
An electrode body including a positive electrode plate and a negative electrode plate,
An exterior body having an opening and accommodating the electrode body,
A sealing plate that seals the opening and
A positive electrode current collector electrically connected to the positive electrode plate and
A method for manufacturing a rectangular secondary battery including a negative electrode current collector electrically connected to the negative electrode plate.
An attachment step of attaching the positive electrode current collector and the negative electrode current collector to the sealing plate, and
In the lateral direction of the sealing plate
On one side of the sealing plate, a first electrode body element including the positive electrode plate having the first positive electrode tab portion and the negative electrode plate having the first negative electrode tab portion is arranged.
On the other side of the sealing plate, a second electrode body element including the positive electrode plate having the second positive electrode tab portion and the negative electrode plate having the second negative electrode tab portion is arranged.
The first positive electrode tab portion and the second positive electrode tab portion are electrically connected to the positive electrode current collector, and the first negative electrode tab portion and the second negative electrode tab portion are electrically connected to the negative electrode current collector. Connection process and
It has a grouping step of combining the first electrode body element and the second electrode body element into one.

According to the above method, the volume occupied by the current collector including the tab portion and the current collector can be made very small, so that a square secondary battery having a higher volume energy density can be easily obtained.

In the connection step, the arrangement of each electrode body element and the order of connection between each tab portion and the current collector are not particularly limited. In the connection step, after the first electrode body element and the second electrode body element are arranged on both sides of the sealing plate, the first positive electrode tab portion and the second positive electrode tab portion are electrically connected to the positive electrode current collector, and the first electrode body element and the second electrode body element are electrically connected to the positive electrode current collector. 1 The negative electrode tab portion and the second negative electrode tab portion may be electrically connected to the negative electrode current collector. Further, in the connection step, the first electrode body element is arranged on one side of the sealing plate, the first positive electrode tab portion is electrically connected to the positive electrode current collector, and the first negative electrode tab portion is electrically connected to the negative electrode current collector. The second electrode body element is arranged on the other side of the sealing plate, the second positive electrode tab portion is electrically connected to the positive electrode current collector, and the second negative electrode tab portion is electrically connected to the negative electrode current collector. May be connected.

The positive electrode current collector is arranged on the sealing plate via a positive electrode insulating member.
It is preferable that the negative electrode current collector is arranged on the sealing plate via the negative electrode insulating member.

The first electrode body element includes a plurality of the positive electrode plates and a plurality of the negative electrode plates.
The first positive electrode tab portion is laminated, and the first negative electrode tab is laminated.
The second electrode body element includes a plurality of the positive electrode plates and a plurality of the negative electrode plates.
It is preferable that the second positive electrode tab portion is laminated and the second negative electrode tab is laminated.

In the grouping step, it is preferable that one surface of the first electrode body element and one surface of the second electrode body element are brought into contact with each other.

In the grouping step, it is preferable to bend the first positive electrode tab portion, the second positive electrode tab portion, the first negative electrode tab portion, and the second negative electrode tab portion.

In the connection process
An auxiliary conductive member is connected in advance to at least one of the first positive electrode tab portion, the second positive electrode tab portion, the first negative electrode tab portion, and the second negative electrode tab portion.
At least one of the first positive electrode tab portion, the second positive electrode tab portion, the first negative electrode tab portion, and the second negative electrode tab portion is the positive electrode current collector or the negative electrode current collector via the auxiliary conductive member. It is preferably electrically connected to the body.

According to the present invention, it is possible to provide a polygonal secondary battery having a high volumetric energy density.

It is a perspective view of the rectangular secondary battery which concerns on embodiment. It is sectional drawing along the line II-II of FIG. It is sectional drawing along the line III-III of FIG. It is sectional drawing along the IV-IV line of FIG. It is sectional drawing along the VV line of FIG. It is sectional drawing along the VI-VI line of FIG. It is a top view of the positive electrode plate and the negative electrode plate which concerns on embodiment. It is a top view of the electrode body element which concerns on embodiment. It is sectional drawing of the vicinity of the current cutoff mechanism along the longitudinal direction of a sealing plate. It is sectional drawing of the vicinity of the current cutoff mechanism along the lateral direction of a sealing plate. It is a figure which shows the battery inner surface side of the sealing plate which attached the current collector and the like. It is sectional drawing along the XII-XII line of FIG. It is a figure corresponding to FIG. 12 of the rectangular secondary battery which concerns on a modification. It is a top view of the auxiliary member. It is a figure corresponding to FIG. 12 of the rectangular secondary battery which concerns on a modification. It is sectional drawing of the electrode body element used in the rectangular secondary battery which concerns on the modification.

The configuration of the polygonal secondary battery 20 according to the embodiment will be described below. The present invention is not limited to the following embodiments.

As shown in FIGS. 1 to 6, the square secondary battery 20 includes a square exterior body 1 having an opening and a sealing plate 2 for sealing the opening. The square exterior body 1 and the sealing plate 2 are preferably made of metal, and can be made of, for example, aluminum or an aluminum alloy. The square exterior body 1 has a bottom portion 1a, a pair of large area side walls 1b, and a pair of small area side walls 1c. The square exterior body 1 is a square bottomed tubular exterior body having an opening at a position facing the bottom portion 1a. In the square exterior body 1, a laminated electrode body 3 in which a plurality of positive electrode plates and a plurality of negative electrode plates are laminated via a separator is housed together with an electrolyte.

The positive electrode plate 4 has a positive electrode core made of metal and a positive electrode active material layer 4a containing a positive electrode active material formed on the positive electrode core body. The positive electrode plate 4 has a positive electrode core body exposed portion 4b on one end side where the positive electrode core body is exposed. It is preferable to use an aluminum foil or an aluminum alloy foil as the positive electrode core. The negative electrode plate 5 has a negative electrode core made of metal and a negative electrode active material layer 5a containing a negative electrode active material formed on the negative electrode core body. The negative electrode plate 5 has a negative electrode core body exposed portion 5b on one end side where the negative electrode core body is exposed. It is preferable to use a copper foil or a copper alloy foil as the negative electrode core. In the square secondary battery 20, the positive electrode core body exposed portion 4b constitutes the positive electrode tab portion 4c, and the negative electrode core body exposed portion 5b constitutes the negative electrode tab portion 5c.

In the electrode body 3, the positive electrode tab portion 4c is laminated on the end portion on the sealing plate 2 side to form a positive electrode tab group (4x, 4y), and the negative electrode tab portion 5c is laminated to form the negative electrode tab group (4c). 5x, 5y) are arranged in a configured state. The laminated positive electrode tab portion 4c is connected to the lead portion 6c of the positive electrode current collector 6. Then, the positive electrode terminal 7 is electrically connected to the positive electrode current collector 6. The laminated negative electrode tab portion 5c is connected to the lead portion 8c of the negative electrode current collector 8. Then, the negative electrode terminal 9 is electrically connected to the negative electrode current collector 8. A pressure-sensitive current cutoff mechanism 40 is provided in the conductive path between the positive electrode plate 4 and the positive electrode terminal 7. The current cutoff mechanism 40 operates when the pressure inside the battery becomes a predetermined value or more, and the current is cut off by cutting the conductive path between the positive electrode plate 4 and the positive electrode terminal 7. A pressure-sensitive current cutoff mechanism 40 may be provided in the conductive path between the negative electrode plate 5 and the negative electrode terminal 9.

The positive electrode terminal 7 is attached to the sealing plate 2 in a state of being electrically insulated from the sealing plate 2 by the internal insulating member 10 and the external insulating member 11. Further, the negative electrode terminal 9 is attached to the sealing plate 2 in a state of being electrically insulated from the sealing plate 2 by the internal insulating member 12 and the external insulating member 13. It is preferable that the inner side insulating members 10 and 12 and the outer side insulating members 11 and 13 are made of resin, respectively. The positive electrode terminal 7 is provided with a terminal through hole 7x, and the terminal through hole 7x is sealed by a terminal plug 7y.

The electrode body 3 is housed in the square exterior body 1 in a state of being covered with the insulating sheet 14. As the insulating sheet 14, it is preferable to use a box-shaped bent resin sheet or a bag-shaped resin sheet. The sealing plate 2 is joined to the opening edge of the square exterior body 1 by laser welding or the like. The sealing plate 2 has an electrolytic solution injection hole 15, and the electrolytic solution injection hole 15 is sealed by a sealing plug 16 after the electrolytic solution is injected. The sealing plate 2 is formed with a gas discharge valve 17 that operates when the pressure inside the battery exceeds a predetermined value and discharges the gas inside the battery to the outside of the battery. The operating pressure of the gas discharge valve 17 is set to a value higher than the operating pressure of the current cutoff mechanism 40.

Next, a method of manufacturing the square secondary battery 20 will be described.

[Preparation of positive electrode plate]
A positive electrode slurry containing lithium nickel-cobalt-manganese composite oxide as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, a carbon material as a conductive agent, and N-methylpyrrolidone (NMP) is prepared. This positive electrode slurry is applied to both sides of a rectangular aluminum foil having a thickness of 15 μm as a positive electrode core. Then, by drying this, N-methylpyrrolidone in the positive electrode slurry is removed, and a positive electrode active material layer is formed on the positive electrode core body. Then, the positive electrode active material layer is compressed so as to have a predetermined thickness. The positive electrode plate thus obtained is cut into a predetermined shape.

[Manufacturing of negative electrode plate]
A negative electrode slurry containing graphite as a negative electrode active material, styrene-butadiene rubber (SBR) as a binder, carboxymethyl cellulose (CMC) as a thickener, and water is prepared. This negative electrode slurry is applied to both sides of a rectangular copper foil having a thickness of 8 μm as a negative electrode core. Then, by drying this, the water in the negative electrode slurry is removed, and the negative electrode active material layer is formed on the negative electrode body. Then, the negative electrode active material layer is compressed so as to have a predetermined thickness. The negative electrode plate thus obtained is cut into a predetermined shape.

FIG. 7 is a plan view of the positive electrode plate 4 ((a) in FIG. 7) and the negative electrode plate 5 ((b) in FIG. 7) after cutting. The positive electrode plate 4 has a rectangular region in which positive electrode active material layers 4a are formed on both sides of the positive electrode core body, and a positive electrode core body exposed portion 4b is formed as a positive electrode tab portion 4c on one side thereof. The negative electrode plate 5 has a rectangular region in which negative electrode active material layers 5a are formed on both sides of the negative electrode core body, and a negative electrode core body exposed portion 5b is formed as a negative electrode tab portion 5c on one side thereof. The size of the positive electrode plate 4 is slightly smaller than the size of the negative electrode plate 5. It is preferable to provide an insulating layer or a protective layer 4d having a higher electrical resistance than the positive electrode core at the root of the positive electrode tab portion 4c. It is also possible to connect another conductive member to the positive electrode core body exposed portion 4b to the negative electrode core body exposed portion 5b to form the positive electrode tab portion 4c to the negative electrode tab portion 5c.

[Preparation of electrode body element]
Fifty positive electrode plates 4 and 51 negative electrode plates 5 are manufactured by the above method, and these are laminated via a rectangular separator made of polyolefin to prepare a laminated electrode body element (3x, 3y). As shown in FIG. 8, in the laminated electrode body element (3x, 3y), the positive electrode tab portion 4c of each positive electrode plate 4 is laminated at one end, and the negative electrode tab portion 5c of each negative electrode plate 5 is laminated. It is made to be. Separator is arranged on both outer surfaces of the electrode body elements (3x, 3y), and each electrode plate and the separator can be fixed in a laminated state by tape 18 or the like. Alternatively, an adhesive layer may be provided on the separator so that the separator and the positive electrode plate 4 and the separator and the negative electrode plate 5 are adhered to each other. The size of the separator in a plan view is the same as that of the negative electrode plate 5 or larger than that of the negative electrode plate 5. The positive electrode plate 4 may be arranged between the two separators so that the peripheral edge of the separator is heat-welded, and then the positive electrode plate 4 and the negative electrode plate 5 may be laminated.

<Attachment of positive electrode terminal and current cutoff mechanism to the sealing plate>
FIG. 9 is a cross-sectional view of the vicinity of the current cutoff mechanism 40 along the longitudinal direction of the sealing plate 2. FIG. 10 is a cross-sectional view of the vicinity of the current cutoff mechanism 40 along the lateral direction of the sealing plate 2.

A through hole is formed in the sealing plate 2 as a positive electrode terminal mounting hole 2a. The outer side insulating member 11 is arranged on the battery outer surface side of the positive electrode terminal mounting hole 2a, and the inner side insulating member 10 and the conductive member 41 are arranged on the battery inner surface side. Then, the positive electrode terminal 7 is inserted from the outside of the battery into the through holes formed in each of the external insulating member 11, the sealing plate 2, the internal insulating member 10, and the conductive member 41, and the tip of the positive electrode terminal 7 is inserted into the conductive member 41. Tighten up. Further, it is preferable to weld the crimped portion at the tip of the positive electrode terminal 7 onto the conductive member 41.

The conductive member 41 preferably has a cup shape having an opening 41x on the electrode body 3 side. The conductive member 41 has a base portion 41a arranged in parallel with the sealing plate 2 and a tubular portion 41b extending from the base portion 41a toward the electrode body 3. The tubular portion 41b may be cylindrical or may be a rectangular tubular portion. The conductive member 41 is made of metal, and is preferably made of, for example, aluminum or an aluminum alloy. The positive electrode terminal 7 is connected to the base portion 41a. The positive electrode terminal 7 and the conductive member 41 may be integrated. In this case, the positive electrode terminal 7 is inserted into the through hole of each component from the inside of the battery and crimped on the outside of the battery.

The internal insulating member 10 is an electrode body from both ends of the insulating member main body 10a arranged between the sealing plate 2 and the base portion 41a of the conductive member 41 and the sealing plate 2 of the insulating member main body 10a in the lateral direction. It has a pair of insulating member first side walls 10b extending to the three sides, and a pair of insulating member second side walls 10c extending from both ends of the insulating member main body 10a in the longitudinal direction toward the electrode body 3. A convex portion 10d is formed on the outer surface of the first side wall 10b of the insulating member.

Next, the deformable plate 42 is arranged so as to close the opening 41x on the electrode body 3 side of the conductive member 41, and the outer peripheral edge of the deformable plate 42 is joined to the conductive member 41 by laser welding or the like. As a result, the opening 41x on the electrode body 3 side of the conductive member 41 is airtightly sealed. The deformed plate 42 is made of metal, and is preferably made of, for example, aluminum or an aluminum alloy. The deformable plate 42 preferably has the same shape as the opening 41x of the conductive member 41. In the square secondary battery 20, the deformed plate 42 has a circular shape in a plan view.

Next, the insulating plate 43 is arranged on the surface of the deformed plate 42 on the electrode body 3 side. The insulating plate 43 includes an insulating plate main body 43a arranged between the deformed plate 42 and the current collector main body 6a of the positive electrode current collector 6, and both ends of the insulating plate main body 43a in the lateral direction. It has a pair of insulating plate first side walls 43b extending from the sealing plate 2 side. The insulating plate main body 43a is formed with an insulating plate through hole 43c, a first protrusion 43d1, a second protrusion 43d2, a third protrusion 43d3, and a fourth protrusion 43d4. Further, a recess 43e is formed on the inner surface of the first side wall 43b of the insulating plate.

A protruding portion 42a formed in the central portion of the deformed plate 42 is inserted into the insulating plate through hole 43c formed in the insulating plate main body portion 43a. Further, the inner surface of the insulating plate first side wall 43b is arranged so as to face the outer surface of the insulating member first side wall 10b. Then, the insulating member 10 and the insulating plate 43 are connected by fitting the convex portion 10d with the concave portion 43e. The recess 43e may be used as a through hole.

A flange portion 41c is provided at the end of the conductive member 41 on the electrode body 3 side. Then, it is preferable to provide a hook fixing portion for being hooked on the flange portion 41c of the conductive member 41 on the surface of the insulating plate main body portion 43a on the sealing plate 2 side. As a result, the insulating plate 43 is fixed to the conductive member 41.

<Positive current collector>
As shown in FIGS. 9 to 11, the positive electrode current collector 6 has a current collector main body 6a, a lead portion 6c, and a current collector connecting portion 6b that connects the current collector main body 6a and the lead portion 6c.

A connection through hole 6d is formed in the current collector main body 6a, and a thin wall portion 6e is formed around the connection through hole 6d. Further, in the thin portion 6e, an annular groove portion 6f is formed so as to surround the connection through hole 6d. The thickness (residual thickness) of the groove portion 6f is smaller than that of the thin portion 6e. Here, the annular groove portion 6f becomes a fragile portion and breaks as the deformation plate 42 is deformed. That is, this fragile part is a part to be broken. It is not necessary to provide both the thin-walled portion 6e and the groove portion 6f because the conductive path may be cut by breaking the fragile portion. Only the thin-walled portion 6e or only the groove portion 6f may be provided. Alternatively, the thin-walled portion 6e and the groove portion 6f may not be provided, and the connecting portion between the deformable plate 42 and the current collector main body portion 6a may be a fragile portion. Alternatively, the deformable plate 42 may be provided with a fragile portion such as a thin-walled portion or a groove portion. The connection through hole 6d is not an indispensable configuration, and a thin portion provided in the current collector main body 6a can be connected to the deformed plate 42.

The current collector main body 6a is provided with a first fixing through hole 6y1, a second fixing through hole 6y2, a third fixing through hole 6y3, and a fourth fixing through hole 6y4. Recesses are provided around each of the first fixing through hole 6y1, the second fixing through hole 6y2, the third fixing through hole 6y3, and the fourth fixing through hole 6y4.

[Installation of positive electrode current collector]
The above-mentioned positive electrode current collector 6 is arranged on the surface of the insulating plate 43 on the electrode body 3 side. At this time, the first protrusion 43d1, the second protrusion 43d2, the third protrusion 43d3, and the fourth protrusion 43d4 formed on the insulating plate 43 are formed in the positive electrode current collector 6, respectively, through the first fixing through hole 6y1. It is inserted into the second fixing through hole 6y2, the third fixing through hole 6y3, and the fourth fixing through hole 6y4. Then, the positive electrode current collector 6 is fixed to the insulating plate 43 by expanding the diameters of the tips of the first protrusion 43d1, the second protrusion 43d2, the third protrusion 43d3, and the fourth protrusion 43d4. As a result, the first fixing portion 70a, the second fixing portion 70b, the third fixing portion 70c, and the fourth fixing portion 70d are formed. In addition, each protrusion may be press-fitted into the fixing through hole.

Gas is sent from the outside of the battery through the terminal through hole 7x formed in the positive electrode terminal 7, and the deformed plate 42 is pressed against the current collector main body 6a of the positive electrode current collector 6. In this state, the edge of the connection through hole 6d provided in the current collector main body 6a of the positive electrode current collector 6 and the deformed plate 42 are joined by laser welding or the like. The connection through hole 6d is not an indispensable configuration, and the current collector main body 6a that does not have the connection through hole 6d can be joined to the deformed plate 42. The terminal through hole 7x is sealed with a terminal plug 7y.

As shown in FIGS. 9 to 11, the current collector main body 6a of the positive electrode current collector 6 is arranged on the inner surface of the insulating plate 43 on the battery side. At the end of the current collector main body 6a, a current collector connecting portion 6b extending from the current collector main body 6a to the sealing plate 2 side is provided. A lead portion 6c is provided so as to extend from the end of the current collector connecting portion 6b on the sealing plate 2 side to the gas discharge valve 17 side along the sealing plate 2. The lead portion 6c is arranged parallel to the sealing plate 2. The lead portion 6c is arranged on the sealing plate 2 via the lead portion insulating member 19 (positive electrode insulating member). The lead portion insulating member 19 may be integrally formed with the internal insulating member 10 or the insulating plate 43.

<Attachment of negative electrode terminal to sealing plate>
A through hole is formed in the sealing plate 2 as a negative electrode terminal mounting hole 2b. The outer side insulating member 13 is arranged on the outer surface side of the negative electrode terminal mounting hole 2b, and the inner side insulating member 12 and the current collector main body 8a of the negative electrode current collector 8 are arranged on the inner surface side. A through hole 8d is provided in the current collector main body 8a. Then, the negative electrode terminal 9 is inserted from the outside of the battery into the through holes formed in each of the external insulating member 13, the sealing plate 2, the internal insulating member 12, and the current collector main body 8a of the negative electrode current collector 8. The tip of the negative electrode terminal 9 is crimped onto the negative electrode current collector 8. Then, the crimped portion of the negative electrode terminal 9 is welded to the negative electrode current collector 8. The internal insulating member 12 serves as a negative electrode insulating member. When the current cutoff mechanism 40 is not provided on the positive electrode side, the positive electrode current collector 6 and the sealing plate 2 of the positive electrode terminal 7 can be attached in the same configuration as the negative electrode side.

<Connection between tab and current collector>
As shown in FIGS. 11 and 12, the first electrode body element 3x is arranged on one side of the sealing plate 2 in the lateral direction (vertical direction in FIG. 11 and horizontal direction in FIG. 12), and the second electrode is placed on the other side. The body element 3y is arranged. Then, the first positive electrode tab group 4x of the first electrode body element 3x is arranged on the lead portion 6c of the positive electrode current collector 6, and the first negative electrode tab group 5x of the first electrode body element 3x is placed on the negative electrode current collector 8. It is arranged on the lead portion 8c. Further, the second positive electrode tab group 4y of the second electrode body element 3y is arranged on the lead portion 6c of the positive electrode current collector 6, and the second negative electrode tab group 5y of the second electrode body element 3y is placed on the negative electrode current collector 8. It is arranged on the lead portion 8c. At this time, in the first electrode body element 3x, each positive electrode tab portion 4c constituting the first positive electrode tab group 4x is bundled on the lower surface 3x2 side of the first electrode body element 3x. Further, each negative electrode tab portion 5c constituting the first negative electrode tab group 5x is bundled on the lower surface 3x2 side of the first electrode body element 3x. Similarly, in the second electrode body element 3y, each positive electrode tab portion 4c constituting the second positive electrode tab group 4y is bundled on the lower surface 3y2 side of the second electrode body element 3y to form the second negative electrode tab group 5y. Each negative electrode tab portion 5c is bundled on the lower surface 3y2 side of the second electrode body element 3y.

Then, a high energy ray such as a laser beam is irradiated from above to the first positive electrode tab group 4x and the second positive electrode tab group 4y arranged on the lead portion 6c of the positive electrode current collector 6, and the first positive electrode tab group 4x And the second positive electrode tab group 4y is welded to the lead portion 6c. Further, a high energy ray such as a laser beam is irradiated from above to the first negative electrode tab group 5x and the second negative electrode tab group 5y arranged on the lead portion 8c of the negative electrode current collector 8, and the first negative electrode tab group 5x And the second negative electrode tab group 5y is welded to the lead portion 8c. As a result, welded portions 50x, 50y, 60x and 60y are formed.

For each of the first electrode body element 3x and the second electrode body element 3y, the positive electrode tab portions 4c are joined to each other by welding or the like in advance before the tab portions are connected to the current collector, and the preliminary joint portions 51x and 51y are joined in advance. It is preferable to form. Similarly, on the negative electrode side, it is preferable to join the negative electrode tab portions 5c to each other in advance to form a preliminary joint portion. The preliminary joint portions 51x and 51y are preferably provided at positions facing the lead portion 6c of the positive electrode current collector 6. As a result, when the positive electrode tab portion 4c is curved in the gathering step, the bending process is suppressed from being hindered by the preliminary joint portion. It is more preferable that the pre-joining portions 51x and 51y are provided in the region of the positive electrode tab portion 4c after the bending treatment, which is arranged parallel to the lead portion 6c.

<Preparation of electrode body>
The first positive electrode tab group 4x, the second positive electrode tab group 4y, the first negative electrode tab group 5x and the second so that the upper surface 3x1 of the first electrode body element 3x and the upper surface 3y1 of the second electrode body element 3y in FIG. 12 are in contact with each other. Bend the negative electrode tab group 5y. As a result, the first electrode body element 3x and the second electrode body element 3y form one electrode body 3 as shown in FIGS. 3 to 6.

<Assembly of square secondary battery>
The electrode body 3 attached to the sealing plate 2 is covered with the insulating sheet 14 and inserted into the square exterior body 1. Then, the sealing plate 2 and the square exterior body 1 are joined by laser welding or the like to seal the opening of the square exterior body 1. Then, a non-aqueous electrolyte containing an electrolyte solvent and an electrolyte salt is injected through the electrolyte injection hole 15 provided in the sealing plate 2. Then, the electrolytic solution injection hole 15 is sealed with the sealing plug 16.

<Manufacturing method of polygonal secondary battery>
According to the above method, the structure of the current collector including the connection portion between the positive electrode tab portion 4c and the positive electrode current collector 6 and the connection portion between the negative electrode tab portion 5c and the negative electrode current collector 8 can be easily achieved without complicating the structure. The space occupied by the current collector can be made smaller. Therefore, a polygonal secondary battery having a higher volumetric energy density can be manufactured by a simpler method.

Further, after connecting the positive electrode tab portion 4c to the positive electrode current collector 6 or connecting the negative electrode tab portion 5c to the negative electrode current collector 8, it is necessary to bend the positive electrode current collector 6 to the negative electrode current collector 8. Therefore, it is possible to prevent damage to the connection portion between the positive electrode tab portion 4c and the positive electrode current collector 6 or the connection portion between the negative electrode tab portion 5c and the negative electrode current collector 8.

A modified example will be described below. In the modified example, the same reference numerals as those of the square secondary battery 20 are given to the same configuration as the above-mentioned square secondary battery 20. Further, a portion not particularly described can have the same configuration as the above-mentioned rectangular secondary battery 20.

<Modification example 1>
FIG. 13A is a diagram corresponding to FIG. 12 of the rectangular secondary battery according to the first modification. As shown in FIG. 13 (a), with the metal auxiliary member 30 arranged on the first positive electrode tab group 4x and the second positive electrode tab group 4y, the first positive electrode tab group 4x and the second positive electrode tab group 4y can be connected to the lead portion 6c of the positive electrode current collector 6.

FIG. 14 is a plan view of the auxiliary member 30. Two slits 30b are formed in the main body 30a of the auxiliary member 30. The slit portion 30b is arranged so as to extend along the longitudinal direction of the sealing plate 2. Bent portions 30c are formed at both ends of the main body portion 30a (both ends in the lateral direction of the sealing plate 2). The bent portion 30c is bent from the main body portion 30a so as to stand up from the main body portion 30a.

As a connection procedure, first, the first positive electrode tab group 4x and the second positive electrode tab group 4y are sandwiched between the auxiliary member 30 and the lead portion 6c of the positive electrode current collector 6. Then, by irradiating the edge of the slit 30b provided in the auxiliary member 30 with a high energy ray such as a laser beam, the auxiliary member 30, the first positive electrode tab group 4x to the second positive electrode tab group 4y, and the positive electrode collection The lead portion 6c of the electric body 6 is welded. When the auxiliary member 30 is provided with the bent portion 30c, it is possible to prevent the metal spatter generated during welding from scattering toward the electrode body element (3x, 3y) side and damaging the electrode body element (3x, 3y).

As shown in FIG. 13A, the first positive electrode tab group 4x is formed in two rows with the welded portions 50x separated from each other in the lateral direction of the sealing plate 2, so that the lead portion 6c of the positive electrode current collector 6 is formed. More firmly connected. The same applies to the welded portion 50y.

As for the negative electrode side, an auxiliary member can be used in the same manner as the positive electrode side. The auxiliary member on the positive electrode side is preferably made of aluminum or an aluminum alloy. The auxiliary member on the negative electrode side is preferably made of copper or a copper alloy.

<Modification 2>
FIG. 13B is a diagram corresponding to FIG. 12 of the rectangular secondary battery according to the second modification. The difference between the modified example 2 and the modified example 1 is the form of the auxiliary member 30, and the way of bundling the positive electrode tab portion 4c and the negative electrode tab portion 5c. It is also possible to divide the auxiliary member 30 into two as in the second modification. That is, one auxiliary member 30 is connected to the first positive electrode tab group 4x, and the other auxiliary member 30 is connected to the second positive electrode tab group 4y. Further, as in the second modification, the positive electrode tab portion 4c may be bundled in the central portion in the stacking direction of the electrode plates in each of the first electrode body element 3x and the second electrode body element 3y.

<Modification example 3>
FIG. 13C is a diagram corresponding to FIG. 12 of the rectangular secondary battery according to the third modification. The difference between the modified example 3 and the modified example 1 is the form of the auxiliary member 30. As in the third modification, the thin portion 30d can be provided instead of providing the slit 30b in the auxiliary member 30. Then, the thin portion 30d is irradiated with a high energy ray such as a laser beam, and the auxiliary member 30 is welded to the first positive electrode tab group 4x to the second positive electrode tab group 4y and the lead portion 6c of the positive electrode current collector 6. Can be done.

<Modification example 4>
FIG. 15 is a diagram corresponding to FIG. 12 of the rectangular secondary battery according to the modified example 4. As shown in FIG. 15, in a state where the electrode body elements (3x, 3y) are tilted with respect to the sealing plate 2, the first positive electrode tab group 4x, the second positive electrode tab group 4y, the first negative electrode tab group 5x, and the first negative electrode tab group 5x. 2 The negative electrode tab group 5y can be connected to the positive electrode current collector 6 and the negative electrode current collector 8, respectively. According to such a method, when the positive electrode lead portion 4c and the negative electrode lead portion 5c are bent in order to combine the first electrode body element 3x and the second electrode body element 3y into one, the positive electrode lead portion 4c and the negative electrode lead portion 4c and the negative electrode lead portion are bent. It is possible to reduce the load applied to the joint portion 5c, the positive electrode lead portion 4c and the positive electrode current collector 6, or the connection portion between the negative electrode lead portion 5c and the negative electrode current collector 8. Therefore, a more reliable rectangular secondary battery can be obtained. The angle θ formed by the electrode body element (3x, 3y) and the sealing plate 2 is preferably 5 ° to 70 °, more preferably 5 ° to 60 °.

<Modification 5>
In the modified examples 1 to 3, an example in which the auxiliary member 30 and the positive electrode tab group (4x, 4y) are simultaneously welded to the lead portion 6c of the positive electrode current collector 6 is shown. However, the auxiliary conductive member can be connected to the positive electrode tab group (4x, 4y) or the negative electrode tab group (5x, 5y) in advance. Then, the auxiliary conductive member joined to the positive electrode tab group (4x, 4y) or the negative electrode tab group (5x, 5y) can be connected to the current collector.

FIG. 16 is a diagram in which an auxiliary conductive member is connected to the first positive electrode tab group 4x of the first electrode body element 3x with respect to the square secondary battery according to the modified example 5. As shown in FIG. 16A, the auxiliary conductive member 300 can be connected to the first positive electrode tab group 4x of the first electrode body element 3x by welding. The welded portion 500x is formed by welding. Then, after that, the auxiliary conductive member 300 is connected to the lead portion 6c of the positive electrode current collector 6. As a method of connecting the auxiliary conductive member 300 to the lead portion 6c of the positive electrode current collector 6, both ends of the auxiliary conductive member 300 can be laser welded to the lead portion 6c of the positive electrode current collector 6.

Further, as shown in FIG. 16B, the first positive electrode tab group 4x of the first electrode body element 3x is sandwiched between the two auxiliary conductive members 300 and 301, and the first positive electrode tab group 4x is assisted. The conductive members 300 and 301 can be connected in advance. A welded portion 500y is formed on the first positive electrode tab group 4x, the auxiliary conductive member 300, and the auxiliary conductive member 301. Then, at least one of the auxiliary conductive members 300 and 301 is connected to the lead portion 6c of the positive electrode current collector 6. The method of connecting the first positive electrode tab group 4x to the auxiliary conductive members 300 and 301, and the method of connecting at least one of the auxiliary conductive members 300 and 301 to the lead portion 6c of the positive electrode current collector 6 are not particularly limited, and resistance welding is used. Ultrasonic welding, laser welding and the like can be used. Further, the first positive electrode tab group 4x and the auxiliary conductive members 300 and 301 may be connected in advance by caulking or the like, and then at least one of the auxiliary conductive members 300 and 301 may be welded to the lead portion 6c of the positive electrode current collector 6. it can.

<Others>
The present invention may be applied to at least one of the positive electrode side and the negative electrode side.

The method of connecting the positive electrode tab portion and the positive electrode current collector and the method of connecting the negative electrode tab portion and the negative electrode current collector are not particularly limited, and resistance welding, welding by irradiation with high energy rays such as a laser, ultrasonic welding, etc. should be used. Can be done. As the high energy ray, a laser, an electron beam, an ion beam or the like can be used.

The electrode body element is not limited to the laminated type. A strip-shaped positive electrode plate and a strip-shaped negative electrode plate can also be wound around the strip-shaped separator to form an electrode body element.

1 ... Square exterior
1a ・ ・ ・ Bottom 1b ・ ・ ・ Large area side wall 1c ・ ・ ・ Small area side wall 2 ・ ・ ・ Seal plate
2a ・ ・ ・ Positive terminal mounting hole 2b ・ ・ ・ Negative terminal mounting hole

3 ... Electrode body 3x ... First electrode body element 3y ... Second electrode body element

4 ... Positive electrode plate 4a ... Positive electrode active material layer 4b ... Positive electrode core body exposed part
4c ... Positive electrode tab part 4d ... Protective layer 4x ... 1st positive electrode tab group 4y ... 2nd positive electrode tab group

5 ... Negative electrode plate 5a ... Negative electrode active material layer 5b ... Negative electrode core body exposed part 5c ... Negative electrode tab part 5x ... First negative electrode tab group 5y ... Second negative electrode tab group

6 ... Positive electrode current collector 6a ... Current collector main body 6b ... Current collector connection 6c ... Lead
6d ・ ・ ・ Through hole for connection 6e ・ ・ ・ Thin wall part
6f ... Groove 6y1 ... First fixing through hole 6y2 ... Second fixing through hole
6y3 ・ ・ ・ 3rd fixing through hole 6y4 ・ ・ ・ 4th fixing through hole

7 ... Positive electrode terminal 7x ... Terminal through hole 7y ... Terminal plug 8 ... Negative current collector 8a ... Current collector body 8c ... Lead part 8d ... Through hole

9 ... Negative electrode terminals 10, 12 ... Internal side insulating member 10a ... Insulating member main body 10b ... Insulating member first side wall
10c ... Insulation member second side wall 10d ... Convex portions 11, 13 ... External side insulation member 14 ... Insulation sheet 15 ... Electrolyte solution injection hole 16 ... Sealing plug 17 ...・ Gas discharge valve 18 ・ ・ ・ Tape 19 ・ ・ ・ Lead insulation member

20 ... Square secondary battery

30 ... Auxiliary member 30a ... Main body 30b ... Slit 30c ... Bent part 30d ... Thin wall part

40 ... Current cutoff mechanism 41 ... Conductive member
41a ・ ・ ・ Base part 41b ・ ・ ・ Cylindrical part 41c ・ ・ ・ Flange part 42 ・ ・ ・ Deformed plate
42a ... Protruding part 43 ... Insulating plate 43a ... Insulating plate main body 43b ... Insulating plate first side wall
43c ・ ・ ・ Insulation plate through hole 43d1 ・ ・ ・ First protrusion 43d2 ・ ・ ・ Second protrusion
43d3 ... 3rd protrusion 43d4 ... 4th protrusion

50x, 50y ... Welded parts 51x, 51y ... Auxiliary joints 60x, 60y ... Welded parts

70a ... 1st fixing part 70b ... 2nd fixing part 70c ... 3rd fixing part 70d ... 4th fixing part 300 ... Auxiliary conductive member 301 ... Auxiliary conductive member

500x ・ ・ ・ Welded part 500y ・ ・ ・ Welded part

Claims (10)

The first electrode body element and the second electrode body element including the positive electrode plate and the negative electrode plate, respectively,
An electrode body including the first electrode body element and the second electrode body element,
An exterior body having an opening and accommodating the electrode body,
A sealing plate that seals the opening and
The positive electrode terminal provided on the sealing plate and
The negative electrode terminal provided on the sealing plate and
A positive electrode current collector electrically connected to the positive electrode plate and the positive electrode terminal,
The negative electrode plate and the negative electrode current collector electrically connected to the negative electrode terminal are provided.
The positive electrode plate has a positive electrode tab portion and has a positive electrode tab portion.
The negative electrode plate has a negative electrode tab portion and has a negative electrode tab portion.
The positive electrode current collector is arranged between the sealing plate and the electrode body.
The negative electrode current collector is a method for manufacturing a rectangular secondary battery arranged between the sealing plate and the electrode body.
The first electrode body element is arranged on one side of the sealing plate in the lateral direction of the sealing plate, and the second electrode body element is arranged on the other side of the sealing plate in the lateral direction of the sealing plate. The positive electrode tab portion of the first electrode body element and the positive electrode tab portion of the second electrode body element are electrically connected to the positive electrode terminal via the positive electrode current collector, and the first electrode body element is described. The first step of setting the negative electrode tab portion and the negative electrode tab portion of the second electrode body element to be electrically connected to the negative electrode terminal via the negative electrode current collector.
After the first step, there is a second step of combining the first electrode body element and the second electrode body element into one.
In the state after the second step, the positive electrode tab portion is connected to the surface of the positive electrode current collector located on the electrode body side, and the negative electrode tab portion is connected to the electrode body side of the negative electrode current collector. A method of manufacturing a square secondary battery connected to the surface on which it is located. The method for manufacturing a rectangular secondary battery according to claim 1, wherein an insulating member is arranged between the sealing plate and the negative electrode current collector. The first electrode body element includes a plurality of the positive electrode plates and a plurality of the negative electrode plates.
The positive electrode tab portion of the first electrode body element is laminated, and the negative electrode tab portion of the first electrode body element is laminated.
The second electrode body element includes a plurality of the positive electrode plates and a plurality of the negative electrode plates.
The method for manufacturing a square secondary battery according to claim 1 or 2, wherein the positive electrode tab portion of the second electrode body element is laminated, and the negative electrode tab portion of the second electrode body element is laminated. The manufacture of a square secondary battery according to claim 1 or 2, wherein the first electrode body element and the second electrode body element are formed by winding the positive electrode plate and the negative electrode plate with a separator. Method. The position where the positive electrode tab portion of the first electrode body element and the welded portion where the positive electrode current collector is welded is separated from the positive electrode tab portion of the second electrode body element and the welded portion where the positive electrode current collector is welded. Formed in
The position where the negative electrode tab portion of the first electrode body element and the welded portion where the negative electrode current collector is welded is separated from the negative electrode tab portion of the second electrode body element and the welded portion where the negative electrode current collector is welded. The method for manufacturing a square secondary battery according to any one of claims 1 to 4, which is formed in 1. A first electrode body element including a first positive electrode plate having a first positive electrode tab portion and a first negative electrode plate having a first negative electrode tab portion,
A second electrode body element including a second positive electrode plate having a second positive electrode tab portion and a second negative electrode plate having a second negative electrode tab portion,
An electrode body including the first electrode body element and the second electrode body element,
An exterior body having an opening and accommodating the electrode body,
A sealing plate that seals the opening and
The positive electrode terminal provided on the sealing plate and
The negative electrode terminal provided on the sealing plate and
A positive electrode current collector that electrically connects the first positive electrode plate, the second positive electrode plate, and the positive electrode terminal.
A negative electrode current collector for electrically connecting the first negative electrode plate, the second negative electrode plate, and the negative electrode terminal is provided.
The positive electrode current collector is arranged between the sealing plate and the electrode body.
The negative electrode current collector is arranged between the sealing plate and the electrode body.
The first positive electrode tab portion and the second positive electrode tab portion are connected to a surface of the positive electrode current collector located on the electrode body side.
The first negative electrode tab portion and the second negative electrode tab portion are a method for manufacturing a square secondary battery connected to a surface of the negative electrode current collector located on the electrode body side.
A step of manufacturing the first electrode body element and the second electrode body element, and
The first electrode body element and the second electrode body element are oriented so that the first positive electrode tab portion and the second positive electrode tab portion face each other and the first negative electrode tab portion and the second negative electrode tab portion face each other. The positive electrode current collector and the negative electrode current collector are arranged between the first electrode body element and the second electrode body element, and the first positive electrode tab portion and the second positive electrode tab portion are the positive electrode. A step of connecting to the current collector and setting the first negative electrode tab portion and the second negative electrode tab portion to be connected to the negative electrode current collector.
The first positive electrode tab portion and the second positive electrode tab portion are electrically connected to the positive electrode terminal via the positive electrode current collector, and the first negative electrode tab portion and the second negative electrode tab portion are the negative electrode current collector. It has a step of putting together the first electrode body element and the second electrode body element in a state of being electrically connected to the negative electrode terminal via a body.
Manufacturing method of polygonal secondary battery. The method for manufacturing a rectangular secondary battery according to claim 6, wherein an insulating member is arranged between the sealing plate and the negative electrode current collector. The first electrode body element includes a plurality of the first positive electrode plates and a plurality of the first negative electrode plates.
The first positive electrode tab portion is laminated, and the first negative electrode tab portion is laminated.
The second electrode body element includes a plurality of the second positive electrode plates and a plurality of the second negative electrode plates.
The method for manufacturing a rectangular secondary battery according to claim 6 or 7, wherein the second positive electrode tab portion is laminated and the second negative electrode tab portion is laminated. The first positive electrode plate and the first negative electrode plate are wound around the separator to prepare the first electrode body element.
The method for manufacturing a square secondary battery according to claim 6 or 7, wherein the second positive electrode plate and the second negative electrode plate are wound via a separator to produce the second electrode body element. The welded portion where the first positive electrode tab portion and the positive electrode current collector are welded is formed at a position separated from the welded portion where the second positive electrode tab portion and the positive electrode current collector are welded.
6. to claim 6, wherein the welded portion in which the first negative electrode tab portion and the negative electrode current collector are welded is formed at a position separated from the welded portion in which the second negative electrode tab portion and the negative electrode current collector are welded. 9. The method for manufacturing a square secondary battery according to any one of 9.