JP2017216118A - Power storage device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device and a method for manufacturing the same capable of improving productivity of an electrode assembly by reducing the number of stacking processes.SOLUTION: An electrode assembly 12 of a secondary battery 10 includes electrode units 30. In each of the electrode units 30, one positive electrode 14 and one electrode accommodating separator 13 are integrated by an adhesive tape 31 adhered to an uncoated portion 15a of the positive electrode 14. The electrode assembly 12 has a layered structure in which a plurality of electrode units 30 are stacked.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power storage device including an electrode assembly that includes a plurality of positive electrode electrodes and electrode storage separators each having a negative electrode electrode stored in a bag-shaped separator, and a method for manufacturing the power storage device.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. As this type of secondary battery, for example, a battery having a stacked electrode assembly in which rectangular sheet-shaped positive electrodes, rectangular sheet-shaped negative electrodes, and separators that insulate them are alternately stacked is known. (For example, refer to Patent Document 1).

JP 2008-130360 A

  However, since the laminated structure of the electrode assembly undergoes a manufacturing process in which the positive electrode, the negative electrode, and the separator are sequentially stacked, the number of stacking processes increases. Therefore, there are problems that the tact time of production is long and the productivity is not good.

  The objective of this invention is providing the manufacturing method of the electrical storage apparatus which can reduce the number of stacking processes, and can improve the productivity of an electrode assembly, and an electrical storage apparatus.

  A power storage device for solving the above problems includes a positive electrode active material layer on both surfaces of a positive electrode metal foil, a positive electrode having an uncoated portion where the positive electrode metal foil is exposed, and a negative electrode active material on both surfaces of the negative electrode metal foil. A power storage device including an electrode assembly having a plurality of electrode storage separators each including a negative electrode including a material layer and stored in a bag-shaped separator, wherein the electrode assembly includes one positive electrode and one positive electrode An electrode unit in which the electrode storage separator is integrated by an adhesive tape attached to the uncoated part and the bag-like separator is alternately arranged between the negative electrode and the positive electrode via the bag-like separator. The gist of the present invention is that it is a layered structure in which a plurality of layers are stacked in a state of being positioned at a position.

  According to this, an electrode assembly is manufactured by stacking a plurality of electrode units. By stacking only one electrode unit, one positive electrode and one negative electrode can be laminated at the same time, and the positive electrode and the negative electrode can be insulated by a bag-like separator. Therefore, the number of stacking steps can be reduced and the time required for stacking can be reduced compared to the case where electrode assemblies are manufactured by stacking one by one with a separator interposed between the positive electrode and the negative electrode. The productivity of the assembly can be improved.

Moreover, about an electrical storage apparatus, it is preferable that the said electrode units adjacent to the lamination direction are non-joining.
According to this, compared with the case where it stacks, for example, joining electrode units, there is no joining process and the time which stacking requires can be shortened.

  In the power storage device, the adhesive tape is a single-sided tape having an adhesive surface on one side, and the adhesive tape is attached to a surface of the uncoated portion that does not face the electrode storage separator, and the uncoated surface. The pressure-sensitive adhesive surface that protrudes beyond the work part may be adhered to the bag-shaped separator.

  According to this, the adhesive surface of the adhesive tape is not exposed to the electrode unit. For this reason, when stacking the electrode units, the electrode units are not joined by the adhesive tape when the stacked positions are shifted.

The power storage device is a secondary battery.
A method of manufacturing a power storage device for solving the above problems includes a positive electrode having a positive electrode active material layer on both sides of a positive electrode metal foil, and an uncoated portion where the positive electrode metal foil is exposed, and both sides of the negative electrode metal foil. An electrode storage separator having a plurality of negative electrode electrodes each including a negative electrode active material layer in a bag-shaped separator, and a method of manufacturing a power storage device including a plurality of electrode assemblies each including a single positive electrode and a single positive electrode An electrode unit in which the electrode storage separator is integrated by an adhesive tape attached to the uncoated part and the bag-like separator, and the positive electrode and the negative electrode are alternately arranged via the bag-like separator. The negative electrode of the electrode housing separator separate from the electrode unit is positioned at the other end in the stacking direction, and the negative electrode of the electrode unit is positioned at one end in the stacking direction. And gist be positioned.

  According to this, an electrode assembly in which the negative electrode is positioned at both ends in the stacking direction is manufactured by stacking a plurality of electrode units and stacking electrode storage separators on the electrode units. By stacking only one electrode unit, one positive electrode and one negative electrode can be laminated at the same time, and the positive electrode and the negative electrode can be insulated by a bag-like separator. Therefore, the number of stacking steps can be reduced and the time required for stacking can be reduced compared to the case of manufacturing an electrode assembly by stacking one by one with a separator interposed between the positive electrode and the negative electrode. The productivity of the assembly can be improved.

Moreover, about the manufacturing method of an electrical storage apparatus, it is preferable to stack | stack the said electrode units adjacent in the lamination direction, without joining.
According to this, compared with the case where it stacks, for example, joining electrode units, there is no joining process and the time which stacking requires can be shortened.

  According to the present invention, the productivity of the electrode assembly can be improved by reducing the number of stacking steps.

Sectional drawing which shows the secondary battery of embodiment. The disassembled perspective view which shows the component of an electrode assembly. The perspective view which shows an electrode unit. Sectional drawing which shows the inside of a secondary battery. The perspective view which shows the process of loading an electrode unit.

Hereinafter, an embodiment in which a power storage device and a method for manufacturing a power storage device are embodied in a secondary battery and a method for manufacturing a secondary battery will be described with reference to FIGS.
As shown in FIG. 1, a secondary battery 10 as a power storage device includes a rectangular parallelepiped case 11 and an electrode assembly 12 accommodated in the case 11. The case 11 includes a case main body 11a made of metal having a bottomed rectangular tube shape (for example, made of aluminum or aluminum alloy) and a lid 11b that closes an opening of the case main body 11a. An electrolyte (electrolytic solution) (not shown) is accommodated in the case 11. The secondary battery 10 of this embodiment is a lithium ion secondary battery.

  The secondary battery 10 includes a positive electrode terminal 18 a fixed to the lid 11 b so as to protrude outside the case 11, and a negative electrode terminal 19 a fixed to the lid 11 b so as to protrude outside the case 11. The positive electrode terminal 18a is electrically connected to the electrode assembly 12 via the positive electrode conductive member 18b. The negative electrode terminal 19a is electrically connected to the electrode assembly 12 via the negative electrode conductive member 19b. The secondary battery 10 includes an insulating member 23 in the case 11 that insulates the negative electrode conductive member 19b and the positive electrode conductive member 18b from the lid 11b.

  As shown in FIG. 2, the electrode assembly 12 includes a plurality of positive electrodes 14 and a plurality of electrode storage separators 13. The electrode assembly 12 is a laminated type in which positive electrodes 14 and electrode storage separators 13 are alternately laminated to form a layer.

  The positive electrode 14 includes a rectangular sheet-like positive metal foil (for example, aluminum foil) 15 and a positive electrode active material layer 16 that covers both surfaces of the positive metal foil 15. The positive electrode 14 includes a first edge portion 14 a at one edge portion of the edge portions along the long side of the positive electrode metal foil 15. The positive electrode 14 includes an uncoated portion 15a along the first edge portion 14a. The uncoated portion 15 a is an exposed portion of the positive electrode metal foil 15 along the first edge portion 14 a of the positive electrode 14. The uncoated portion 15a includes a positive electrode tab 17 having a shape protruding from the first edge portion 14a.

  In the present embodiment, the side along the first edge portion 14 a is one side of the positive electrode 14. Moreover, in the positive electrode 14, the edge part along the other long side which is the other side of the 1st edge part 14a is made into the 2nd edge part 14b, and the 1st edge part 14a and the 2nd edge part 14b are connected. Edge portions along the pair of short sides are respectively referred to as third edge portions 14c.

  The electrode storage separator 13 includes a bag-shaped separator 20 and a negative electrode 24 stored in the bag-shaped separator 20. The negative electrode 24 includes a rectangular sheet-like negative electrode metal foil (for example, copper foil) 25 and a negative electrode active material layer 26 that covers both surfaces of the negative electrode metal foil 25. The negative electrode 24 includes a first edge 24 a at one of the edges along the long side of the negative electrode metal foil 25. The negative electrode 24 has a negative electrode tab 27 having a shape protruding from the first edge 24a.

  In the present embodiment, the side along the first edge 24 a is one side of the negative electrode 24. Moreover, in the negative electrode 24, the edge part along the other long side which is the other side of the 1st edge part 24a is made into the 2nd edge part 24b, and the 1st edge part 24a and the 2nd edge part 24b are connected. Edge portions along the pair of short sides are respectively referred to as third edge portions 24c.

  The length of the first edge 24 a of the negative electrode 24 is longer than the length of the first edge 14 a of the positive electrode 14, and the length of the second edge 24 b of the negative electrode 24 is the length of the positive electrode 14. Longer than the length of the second edge 14b. Further, the length of the third edge 24 c of the negative electrode 24 is longer than the length of the third edge 14 c of the positive electrode 14. Therefore, the negative electrode 24 is slightly larger than the positive electrode 14, and the negative electrode active material layer 26 is slightly larger than the positive electrode active material layer 16.

  The bag-like separator 20 includes rectangular sheet-like separator members 21 that face each other. Each separator member 21 is made of an insulating resin (for example, polyethylene). The two separator members 21 have the same shape and the same size, and are slightly larger than the negative electrode 24. Each separator member 21 has a protruding portion 22 that protrudes from the first to third edge portions 24 a to 24 c of the negative electrode 24 in a state where the negative electrode 24 is overlapped. The bag-shaped separator 20 is manufactured by welding the protruding portions 22 of the separator member 21. The welded portion of the bag-like separator 20 is formed by welding the protruding portion 22 along the first to third edge portions 24 a to 24 c which are the four sides of the negative electrode 24.

The electrode assembly 12 includes an electrode unit 30.
As shown in FIG. 3 or FIG. 4, the electrode unit 30 has a structure in which one positive electrode 14 and one electrode storage separator 13 are integrated. In the electrode unit 30, the positive electrode 14 and the electrode storage separator 13 are integrated with an adhesive tape 31. The adhesive tape 31 is a single-sided tape having an adhesive surface 31a on one side.

  The adhesive tape 31 is attached to the outer surface of the uncoated portion 15 a of the positive electrode 14 that does not face the electrode storage separator 13. The adhesive tape 31 sticks to one side of the uncoated part 15a, and the adhesive surface protrudes from the edge of the uncoated part 15a. The adhesive surface 31 a that protrudes beyond the uncoated portion 15 a is adhered to the bag-shaped separator 20 of the electrode storage separator 13. In addition, the adhesive tape 31 is affixed over the whole uncoated part 15a of the positive electrode 14, and has covered the whole surface of the uncoated part 15a.

  In the stacking direction of the electrode assembly 12, the adhesive tape 31 overlaps a part of the negative electrode active material layer 26. However, in the negative electrode active material layer 26, the portion where the adhesive tape 31 overlaps is a portion that protrudes from the positive electrode active material layer 16, and the adhesive tape 31 does not overlap the positive electrode active material layer 16. The electrode unit 30 has a two-layer structure of the electrode housing separator 13 and the positive electrode 14.

  The electrode assembly 12 has a layered structure in which the electrode storage separators 13 and the positive electrodes 14 are alternately stacked, and the electrode storage separator 13 is stacked at the other end in the stacking direction. In the electrode assembly 12, the electrode units 30 adjacent to each other in the stacking direction are not joined. However, the electrode assembly 12 is held in a laminated state by a holding tape (not shown), and the entire surface of the positive electrode active material layer 16 is maintained facing the negative electrode active material layer 26 via the separator member 21.

  As shown in FIG. 1, in the electrode assembly 12, the plurality of electrode units 30 and one electrode storage separator 13 are arranged such that the positive electrode tabs 17 are arranged in a row along the stacking direction, and the negative electrode tabs 27 are stacked in a state of being arranged in a row along the stacking direction. A positive electrode terminal 18a is connected to all the laminated positive electrode tabs 17 via a positive electrode conductive member 18b, and a negative electrode terminal 19a is connected to all the laminated negative electrode tabs 27 via a negative electrode conductive member 19b. Yes.

  As shown in FIG. 4, the electrode housing separator 13 of the electrode unit 30 is located at one end in the stacking direction of the electrode assembly 12, and the electrode housing separator 13 different from the electrode unit 30 is positioned at the other end in the stacking direction. To position. Therefore, the negative electrode 24 accommodated in the bag-shaped separator 20 is positioned at both ends of the electrode assembly 12 in the stacking direction. The negative electrodes 24 at both ends in the stacking direction of the electrode assembly 12 are insulated from the case 11 by the bag-shaped separator 20. And the negative electrode 24 and the positive electrode 14 are alternately located through the bag-shaped separator 20 along the lamination direction of the electrode assembly 12.

Next, a method for manufacturing the electrode assembly 12 will be described.
First, the electrode unit 30 is manufactured.
As shown in FIG. 3, the positive electrode active material layer 16 is opposed to the negative electrode active material layer 26 with the separator member 21 interposed therebetween, and the electrode storage separator 13 and the positive electrode 14 are overlapped, and the positive electrode tape 31 is attached to the positive electrode active material layer 16. The electrode 14 and the electrode storage separator 13 are joined.

  Next, as shown in FIG. 5, the electrode unit 30 is placed on the lamination table 40. At this time, the electrode storage separator 13 is on the lower side and the positive electrode 14 is on the upper side. Then, another electrode unit 30 is stacked on the electrode unit 30 on the stacking table 40. At this time, the electrode unit 30 is stacked so that the electrode storage separator 13 is on the lower side and the positive electrode 14 is on the upper side. The electrode unit 30 is stacked at a position where the entire surface of the positive electrode active material layer 16 faces the negative electrode active material layer 26 of the negative electrode 24. Thereafter, a predetermined number of electrode units 30 are stacked in the same manner as described above. Finally, one electrode storage separator 13 different from the electrode unit 30 is stacked on the electrode unit 30 which is the other end in the stacking direction. At this time, the electrode storage separator 13 is stacked on the entire surface of the positive electrode active material layer 16 of the positive electrode 14 of the electrode unit 30 at a position where the negative electrode active material layer 26 faces. Then, the electrode assembly 12 is manufactured.

According to the above embodiment, the following effects can be obtained.
(1) The electrode assembly 12 has a layered structure in which a plurality of electrode units 30 and one electrode storage separator 13 are stacked. The electrode unit 30 has a structure in which one positive electrode 14 and one electrode storage separator 13 are integrated in advance. For this reason, by stacking only one electrode unit 30, one positive electrode 14 and one negative electrode 24 can be stacked simultaneously, and the positive electrode 14 and the negative electrode 24 are insulated by the bag-shaped separator 20. It can be in the state. Therefore, as compared with the case where the separators are interposed between the positive electrode 14 and the negative electrode 24 and stacked one by one, the number of stacking steps can be reduced, and the time required for stacking can be shortened. Productivity can be improved.

  (2) The adhesive tape 31 is attached to the uncoated part 15 a of the positive electrode 14. For this reason, the area of the positive electrode active material layer 16 is not reduced by sticking the adhesive tape 31, and the capacity of the secondary battery 10 is not reduced.

  (3) In the electrode assembly 12, the electrode units 30 adjacent in the stacking direction are not joined. For this reason, when stacking the electrode units 30, there is no need to attach a joining member such as the adhesive tape 31, and the production speed of the electrode assembly 12 can be increased.

  (4) In the electrode assembly 12, the uncoated portion 15 a of the positive electrode 14 is covered with the adhesive tape 31. For this reason, when a force is applied to the secondary battery 10 in the stacking direction of the electrode assembly 12 and the secondary battery 10 is crushed, the uncoated portion 15a of the positive electrode 14 and the negative electrode tab 27 of the negative electrode 24 Short circuit can be suppressed. The uncoated portion 15a and the negative electrode tab 27 are metal foils, and when they are short-circuited, the resistance is small and the calorific value is likely to be large. However, since the short circuit can be suppressed by the adhesive tape 31, it is possible to suppress an increase in the amount of heat generated by the secondary battery 10 at the time of the collapse.

  (5) In the electrode unit 30, the adhesive tape 31 is affixed on the surface which does not oppose the electrode storage separator 13 among both surfaces of the uncoated part 15a. The adhesive surface 31 a of the adhesive tape 31 is not exposed outside the electrode unit 30. For this reason, when the electrode units 30 are stacked, the other electrode unit 30 can be prevented from sticking to the adhesive surface 31 a of the adhesive tape 31. For this reason, when the position where the electrode unit 30 is stacked is displaced, the electrode units 30 are not joined to each other, and the labor for correcting the displacement can be saved.

  (6) The adhesive tape 31 is a single-sided tape having an adhesive surface 31a only on one side. When manufacturing the electrode unit 30, if the adhesive tape 31 is stuck from the uncoated part 15a toward the electrode containing separator 13 in a state where the electrode housing separator 13 and the positive electrode 14 are overlapped, the uncoated part 15a. The adhesive tape 31 is attached to the bag-like separator 20 and the adhesive surface 31a protruding from the uncoated part 15a is attached. For this reason, manufacture of the electrode unit 30 becomes easier than the case where the positive electrode 14 and the electrode storage separator 13 are stuck in a predetermined position using a double-sided tape.

In addition, you may change the said embodiment as follows.
In the electrode unit 30, the adhesive tape 31 is a double-sided tape, and the adhesive tape 31 has a surface facing the electrode storage separator 13 on both surfaces of the uncoated portion 15 a and an electrode storage separator 13 facing the uncoated portion 15 a. The positive electrode 14 and the electrode storage separator 13 may be integrated.

(Circle) the electrode units 30 adjacent to the lamination direction may be joined by the double-sided tape.
If the positive electrode 14 and the electrode storage separator 13 can be integrated with the adhesive tape 31, the adhesive tape 31 may not be attached to cover the entire surface of the uncoated part 15a. For example, the uncoated part The adhesive tape 31 may be stuck in a state where a part of 15a is exposed.

Alternatively, the positive electrode 14 and the electrode storage separator 13 may be integrated by attaching a plurality of adhesive tapes 31 to the uncoated portion 15a.
The electrode housing separator 13 welds all the protruding portions 22 protruding from the first to third edge portions 24 a to 24 c of the negative electrode 24 in the pair of separator members 21, and welds the welded portions along the four sides of the negative electrode 24. It was set as the structure which has. However, the structure of the electrode storage separator 13 is not limited to this. For example, the long rectangular separator member 21 is bent from the middle in the longitudinal direction, the second edge 24b of the negative electrode 24 is brought into contact with the bent side, and the negative electrode 24 is sandwiched between the bent separator member 21. And in the separator member 21, the part protruded from both the 3rd edge parts 24c of the negative electrode 24 is welded, it is good also as the bag-shaped separator 20, and it is good also as the electrode storage separator 13. FIG.

  In the embodiment, the welded portion is formed along the entire first to third edge portions 24 a to 24 c of the negative electrode 24, but the weld portion is the first to third edge portions of the negative electrode 24. You may form in spots along 24a-24c.

O If the electrode storage separator 13 and the positive electrode 14 can be integrated by the adhesive tape 31, the adhesive tape 31 may be stuck to the positive electrode tab 17 among the uncoated parts 15a.
Regarding the manufacture of the electrode assembly 12, in the embodiment, the stacking is started from the electrode unit 30 and finally the one electrode storage separator 13 is stacked. However, the stacking order may be reversed. On the lamination table 40, the one electrode storage separator 13 which will be located in one end of the lamination direction is mounted, and the electrode unit 30 is stacked on the electrode storage separator 13. At this time, the positive electrode 14 of the electrode unit 30 is on the lower side, and the electrode storage separator 13 is on the upper side. Thereafter, a predetermined number of electrode units 30 are stacked, and when the electrode unit 30 positioned at the other end in the stacking direction is stacked, the electrode assembly 12 is manufactured.

  The method of stacking the electrode unit 30 may be other than the method of stacking the electrode unit 30 and the electrode storage separator 13 on the stacking table 40. For example, the electrode unit 30 and the electrode storage separator 13 may be dropped by their own weight and stacked.

  The secondary battery 10 is a lithium ion secondary battery, but is not limited thereto, and may be another secondary battery. In short, any material may be used as long as ions move between the positive electrode active material and the negative electrode active material and transfer charge.

  -It may be embodied in a power storage device such as an electric double layer capacitor.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 12 ... Electrode assembly, 13 ... Electrode storage separator, 14 ... Positive electrode, 15 ... Positive electrode metal foil, 15a ... Uncoated part, 16 ... Positive electrode active material layer, 20 ... Bag 24, negative electrode, 25 ... negative electrode metal foil, 26 ... negative electrode active material layer, 30 ... electrode unit, 31 ... adhesive tape, 31a ... adhesive surface.

Claims (6)

A positive electrode provided with a positive electrode active material layer on both sides of the positive metal foil, and an uncoated portion where the positive metal foil is exposed;
A negative electrode having negative electrode active material layers on both sides of a negative electrode metal foil, an electrode storage separator having a plurality of electrode storage separators stored in a bag-shaped separator,
The electrode assembly includes:
An electrode unit in which one positive electrode and one electrode storage separator are integrated with an adhesive tape attached to the uncoated portion and the bag-shaped separator is interposed via the bag-shaped separator. A power storage device having a layered structure in which a plurality of the negative electrodes and the positive electrodes are alternately stacked.   The power storage device according to claim 1, wherein the electrode units adjacent in the stacking direction are not joined.   The pressure-sensitive adhesive tape is a single-sided tape having a pressure-sensitive adhesive surface on one side, and the pressure-sensitive adhesive tape is affixed to a surface of the uncoated part that does not face the electrode storage separator and protrudes beyond the uncoated part. The power storage device according to claim 1 or 2, wherein an adhesive surface is attached to the bag-like separator.   The power storage device according to any one of claims 1 to 3, wherein the power storage device is a secondary battery. A positive electrode provided with a positive electrode active material layer on both sides of the positive metal foil, and an uncoated portion where the positive metal foil is exposed;
A negative electrode having a negative electrode active material layer on both sides of a negative electrode metal foil, an electrode storage separator having a plurality of electrode storage separators stored in a bag-shaped separator,
An electrode unit in which one positive electrode and one electrode storage separator are integrated with an adhesive tape attached to the uncoated portion and the bag-shaped separator is interposed via the bag-shaped separator. A plurality of the positive electrode and the negative electrode are alternately stacked, the negative electrode of the electrode unit is positioned at one end in the stacking direction, and the electrode storage separator different from the electrode unit is positioned at the other end in the stacking direction A method of manufacturing a power storage device, wherein the negative electrode is positioned.   The method for manufacturing a power storage device according to claim 5, wherein the electrode units adjacent in the stacking direction are stacked without being joined.

Images