JP2007213948A - Manufacturing method of electrode group for rectangular battery, and electrode group for rectangular battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing technique for minimizing weaving in winding an electrode group into a nearly oval shape when a winding type manufacturing method is employed in formation of the electrode group in a manufacturing process of a rectangular battery. <P>SOLUTION: This manufacturing technique includes: an active material filling process for filling or applying an active material in/to a positive electrode core material in a positive electrode plate 1 and a negative electrode core material in a negative electrode plate 2; a rolling process for rolling the positive electrode plate 1 and the negative electrode plate 2 to set the thickness thereof at a predetermined value; and a winding process for winding the positive electrode plate 1 and the negative electrode plate 2 to set each cross section thereof into a nearly oval shape while projecting respective core material exposure parts 4 and 5 in the positive electrode plate 1 and the negative electrode plate 2 in directions opposite to each other from the facing part of both the electrode plates 1 and 2. The core material exposure parts 4 and 5 have, at equal intervals, guide holes each having a longitudinal direction in the winding circumferential direction. In the winding process, by using pin-like tools 8 piercing the guide holes, the pin-like tools 8 are made to pierce the guide holes in every winding. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a prismatic battery electrode group formed by winding a strip-shaped positive electrode plate, a strip-shaped negative electrode plate, and a strip-shaped separator, and a rectangular battery electrode group.

  In recent years, portable information devices such as mobile phones and notebook computers have become widespread. These devices aim to further improve performance, weight, and size. For this reason, secondary batteries used as power sources for such portable information devices are also required to be smaller and lighter and have higher energy density.

  On the other hand, expectations for electric vehicles are rising from the external environment such as rising gasoline prices and consideration for global warming. A so-called hybrid vehicle that uses a gasoline engine and an electric motor as a power source is also commercially available.

  Needless to say, a secondary battery is used as a power source in electric vehicles and hybrid vehicles. The secondary battery is also required to be smaller and lighter, have higher energy density and output, have a longer life, lower cost, and improve reliability.

Storage space is limited for both portable information devices, electric and hybrid vehicles.
On the other hand, many of the conventional secondary batteries have a cylindrical shape, which is not preferable because a gap is generated when stored in a limited storage space.
Therefore, rectangular batteries are the mainstream instead of cylindrical batteries. As a representative technique related to the prismatic battery, there is a technique described in Patent Document 1, for example.

  In Patent Document 1, “in the electrode plate group in which a large number of positive plates and a large number of negative plates are laminated via separators, the opposite side edges of the positive and negative plates protrude from the opposing portions of the electrode plates. By making the protruding portion a lead portion, the average distance from the entire surface of the electrode plate to the current collector plate is shortened. Thereby, while reducing the resistance value inside a battery, the utilization factor of an electrode active material is raised and a battery output is improved. Is described.

  Patent Document 2 discloses that “a pair of current collectors are provided at both ends of an electrode group formed by winding a belt-like positive electrode plate, a belt-like negative electrode plate, and a belt-like separator. Thereby, the opposing area of the electrode plate is increased, and the resistance value inside the battery is reduced. Is described.

JP 2001-93508 A Japanese Patent Laid-Open No. 2001-266928

  The prismatic battery proposed in Patent Document 1 (Japanese Patent Laid-Open No. 2001-93508) described above is a technique in which a positive electrode plate and a negative electrode plate having a predetermined size are stacked via a separator to form an electrode plate group. In order to realize the demand for higher output using this technique, the reaction area between the positive electrode plate and the negative electrode plate is increased by increasing the number of electrode plates. Increasing the number of electrode plates increases the number of electrode plate processing steps and increases the manufacturing cost.

  The technique proposed in Patent Document 2 (Japanese Patent Laid-Open No. 2001-266928) described above discloses a technique for forming a wound electrode plate group. If this technology can be used as it is, the number of electrode plate processing steps, which is a drawback of the technology disclosed in Patent Document 1, will not be greatly increased, and the demand for higher output can be realized at lower cost.

However, it has been found that the manufacturing process for forming the winding type electrode plate group for the prismatic battery is likely to cause “winding deviation” in the winding process. This will be described with reference to FIGS.
3 and 4 show an electrode group 17 formed by being wound through a belt-like positive electrode plate 1, a belt-like negative electrode plate 2, and a belt-like separator 3. FIG. 5 shows a state in which the pair of current collectors 12 and 12 are joined to the end faces of the core material exposed portions 4 and 5 in the electrode group 17.

“Winding misalignment” refers to a direction perpendicular to the longitudinal direction of the positive electrode plate 1, the negative electrode plate 2, and the separator 3 during the winding of the long strip-shaped positive electrode plate 1, negative electrode plate 2, and separator 3 (see FIG. 5). That is, the sheet is wound while being shifted in the vertical direction).

  When this winding deviation occurs, there are irregularities on the end faces of the core material exposed portions 4 and 5 of the electrode group 17, so that bonding failure occurs when the current collector plates 12 and 12 are bonded. As a further undesirable state, there is a possibility that a short circuit will occur before the current collector plates 12 are joined.

  The problem to be solved by the present invention is to minimize winding misalignment when winding in a substantially oval shape when a winding type manufacturing method is adopted in forming the electrode plate group in the manufacturing process of the rectangular battery. To provide manufacturing technology.

  As means for solving the above problems, the present application discloses the following invention.

(Claim 1)
According to the first aspect of the present invention, a strip-shaped positive electrode plate (1) and a strip-shaped negative electrode plate (2) are disposed, and a separator (3) is positioned between the positive electrode plate (1) and the negative electrode plate (2). The present invention relates to a manufacturing method for manufacturing an electrode group by winding them.
That is, an active material filling step of filling or applying an active material to the positive electrode core material in the positive electrode plate (1) and the negative electrode core material in the negative electrode plate (2), and the positive electrode plate (1) and the negative electrode plate (2) rolling step of rolling to a predetermined thickness, and the core material exposed portions (4, 5) in the positive electrode plate (1) and the negative electrode plate (2) so that the cross section is substantially oval. And a winding step of winding so that the cross section is substantially oval while protruding from opposite portions of the bipolar plates (1, 2) to opposite sides. In the core material exposed portions (4, 5) of the positive electrode plate (1) and the negative electrode plate (2), guide holes (6) at least partially matching when overlapped by winding are formed. And in the said winding process, it is the manufacturing method of the electrode group for square batteries which made it wind, inserting the pin-shaped jig | tool (8) in the said guide hole (6) for every turn.

The pin-shaped jig (8) is fitted in the guide hole (6) in the core exposed portion (4, 5) for each turn, and the displacement in the direction perpendicular to the longitudinal direction of the electrode plate, that is, the winding displacement of the electrode group. Can be almost suppressed.
If the occurrence of winding deviation can be suppressed, the reduction of the contact area between the positive electrode plate (1) and the negative electrode plate (2) can be eliminated, and the accompanying output decrease can be prevented. In addition, when welding the current collector to the electrode group, this contributes to suppressing welding variation due to insufficient contact and stabilizes the output characteristics of the final prismatic battery.

The pin-shaped jig (8) is desirably provided on both sides along the winding direction of the core material exposed portion (4) of the positive electrode plate (1) and the core material exposed portion (5) of the negative electrode plate (2). This is because if the pin-shaped jig (8) is on both sides, it is easier to prevent winding displacement than on one side.
More preferably, two pin-shaped jigs (8) are provided on each side. This is because winding deviation can be effectively prevented. In the case of one by one, it is desirable to provide at diagonal positions.

  When the pin-shaped jig (8) is wound in a substantially oval shape with a chamfered plate-shaped winding core as a core material, for example, the pin-shaped jig (8) is erected on the plate-shaped body that forms the winding core. It is easy to handle and convenient. (In FIG. 1, the winding core is not shown). However, the present invention is not limited to this method.

(Claim 2)
Invention of Claim 2 limited the manufacturing method of the electrode group for square batteries of Claim 1,
The guide hole (6) is an oval hole whose longitudinal direction is the winding direction.

The reason why the guide hole (6) is “oval” is to make it easier for the pin-shaped jig (8) to penetrate in the winding process.
The diameter of the pin-shaped jig (8) is equal to or smaller than the short diameter of the guide hole (6) made of an oval hole, but the closer to the short diameter, the more preferable it contributes to prevention of winding displacement.

(Claim 3)
Invention of Claim 3 limited the manufacturing method of the electrode group for square batteries in any one of Claim 1 and Claim 2,
An active material of the positive electrode plate (1) has nickel hydroxide as a main component, and the active material of the negative electrode plate (2) has a hydrogen storage alloy as a main component. Related.
That is, the present invention is suitable as a method for producing a prismatic battery electrode group for a nickel metal hydride battery.

(Claim 4)
Invention of Claim 4 limited the electrode group for square batteries in any one of Claim 1 and Claim 2,
The active material of the positive electrode plate (1) is mainly composed of a lithium-containing metal compound, and the active material of the negative electrode plate (2) is mainly composed of a carbon material.
That is, this invention is suitable also as a manufacturing method of the square battery electrode group for lithium ion batteries.

(Claim 5)
According to the fifth aspect of the present invention, a strip-shaped positive electrode plate (1) and a strip-shaped negative electrode plate (2) are disposed, and a separator (3) is positioned between the positive electrode plate (1) and the negative electrode plate (2). Thus, the present invention relates to an electrode group that is manufactured by being wound so that the cross section is substantially oval.
That is, the core material exposed portions (4, 5) in the positive electrode plate (1) and the negative electrode plate (2) are wound while projecting from the opposite portions of the two electrode plates to the opposite sides, and overlapped by the winding. In this case, the rectangular battery electrode group is characterized in that a guide hole (6) at least partially matching is formed.

  If the active material of the positive electrode plate (1) is mainly composed of nickel hydroxide and the active material of the negative electrode plate (2) is mainly composed of a hydrogen storage alloy, the prismatic shape of the nickel metal hydride battery It becomes a battery electrode group.

  If the active material of the positive electrode plate (1) is based on a lithium-containing metal compound and the active material of the negative electrode plate (2) is based on a carbon material, the active material for a lithium ion battery It becomes a square battery electrode group.

  According to the present invention, the core material exposed portion in the positive electrode plate and the negative electrode plate is provided with a guide hole that at least partially matches when overlapped by winding, and the pin-shaped jig is inserted into the guide hole for each turn. Therefore, it is possible to minimize the winding deviation when forming the electrode plate group in the manufacturing process of the rectangular battery.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a manufacturing procedure of an electrode group for a prismatic battery according to the present invention.
In this embodiment, the positive electrode plate, the separator, and the negative electrode plate that are cut into predetermined dimensions as shown in FIG. It is formed by winding.

  The core material exposed portions 4 and 5 in the positive electrode plate 1 and the negative electrode plate 2 are provided with guide holes 6 having an oval shape with the circumferential direction of winding as a longitudinal direction at equal intervals. The core material exposed portions 4 and 5 in the positive electrode plate 1 and the negative electrode plate 2 penetrate the guide hole 6 through the pin-shaped jig 8 for each winding.

  Although not shown in FIG. 1, the chamfered plate-shaped winding core is wound as a core material so as to form a substantially oval shape, and the pin-shaped jig 8 forms the winding core. Stands on a plate-like body. The position is one at a diagonal position.

The diameter of the pin-shaped jig 8 was almost the same as the short diameter of the guide hole 6 which is an oval hole.
When the winding is completed, the pin-shaped jig 8 is removed, and the winding core (not shown) is also removed.

The positive electrode plate 1 is formed by filling a foamed nickel core material with a positive electrode active material mainly composed of nickel hydroxide. The width of the foamed nickel core material is 45 mm, the width of the filling part is 40 mm, and a 5 mm uncoated part (core material exposed part 4) not filled with the positive electrode active material is provided at one end in the width direction. . Then, after the nickel lead having the same width as that of the core material exposed portion 4 is joined to the uncoated portion, the guide holes 6 are provided at equal intervals.
In addition, the capacity | capacitance of the positive electrode plate 1 is about 7 Ah.

The negative electrode plate 2 is a metal porous plate (punching metal) coated with a paste mainly composed of a fine powder of a hydrogen storage alloy as a negative electrode active material. Further, an uncoated portion (core material exposed portion 5) where no negative electrode active material is applied is provided 5 mm from one end in the width direction. In the core exposed portion 5, the guide holes 6 are provided at equal intervals.
The capacity of the negative electrode plate is about 10 Ah.

  In addition, what has the guide hole 6 previously as a core material of the positive electrode plate 1 and the negative electrode plate 2 is also employable.

  Separator 3 concerning this embodiment is formed with the nonwoven fabric made from the polypropylene which performed sulfonation processing. A polyamide resin non-woven fabric can also be employed.

  The positive electrode plate 1 and the negative electrode plate 2 are in a state in which the positive and negative core material exposed portions 4 and 5 protrude from the opposite portions to the opposite sides while the respective active material portions are opposed to each other through the separator 3. Then, the chamfered winding core (not shown) is wound so as to form a substantially oval shape so that the winding height is 50 mm. Moreover, the pin-shaped jig | tool 8 is inserted in the guide hole 6 for every winding, and an electrode group is formed.

In the above-described embodiment, the nickel metal hydride battery has been exemplified. However, the present invention can also be used for a technique for manufacturing a lithium ion battery.
Other than using aluminum foil as the core material of the positive electrode plate, lithium-containing metal compound (for example, lithium cobaltate) as the active material, copper foil as the core material of the negative electrode plate, and carbon material (for example, graphite) as the active material This is because the basic electrode group structure is the same as that of a nickel metal hydride battery.

  FIG. 2A is a measurement of variations related to the winding height (total height) of 20 cells of the electrode group manufactured in the above-described embodiment. Moreover, FIG. 2B measures the dispersion | variation regarding the winding height of 20 cells of electrode groups manufactured by the conventional manufacturing method shown in FIG.

  As shown in FIG. 2A, the variation (σ value) of the electrode group manufactured in the above embodiment is suppressed to less than half compared to the electrode group manufactured by the conventional manufacturing method shown in FIG. 2B. I understand that.

  Furthermore, the result of having measured the flatness (unevenness of the surface which welds a current collector plate) of the core material exposure part of the said electrode group is shown to FIG. 2C and FIG. 2D. Similar to the data relating to the winding height of the electrode group described above, the flatness of the electrode group manufactured in the above-described embodiment is as shown in FIG. 2C. The electrode group manufactured by the conventional manufacturing method shown in FIG. The variation is smaller than that of 0 and is in the vicinity of 0 (mm). That is, it can be seen that there are few irregularities and it is extremely close to a flat surface.

  As is clear from the above examples, the displacement of the electrode plate was suppressed by inserting the pin-shaped jig through the guide hole every time in the technique according to the present invention, that is, in the winding process.

  The present invention can be used mainly in the field of manufacturing secondary batteries and in the field of manufacturing secondary battery parts and members.

It is a perspective view which shows the manufacture procedure of the electrode group for square batteries which concerns on this invention. It is a bar graph which shows the experimental result by an Example. It is a perspective view which shows the manufacture procedure of the conventional square battery electrode group. It is the perspective view and side view which show the conventional square battery electrode group. It is a perspective view which shows the manufacturing procedure of the conventional square battery unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Core material exposed part (positive electrode)
DESCRIPTION OF SYMBOLS 5 Core material exposed part (negative electrode) 6 Guide hole 8 Pin-shaped jig | tool 12 Current collecting plate 121 Upper part of current collecting plate 122 Welding part 17 Electrode group

Claims (5)

A production method for producing an electrode group by winding a belt-like positive electrode plate and a belt-like negative electrode plate with a separator positioned between the positive electrode plate and the negative electrode plate,
An active material filling step of filling or applying an active material to the positive electrode core material in the positive electrode plate and the negative electrode core material in the negative electrode plate;
A rolling step of rolling the positive electrode plate and the negative electrode plate to a predetermined thickness;
A winding step of winding each core material exposed portion in the positive electrode plate and the negative electrode plate so that the cross-section is substantially oval while projecting from the opposing portions of the two electrode plates to the opposite sides;
In the core material exposed portion in the positive electrode plate and the negative electrode plate, a guide hole that at least partially matches when overlapped by winding is formed,
In the winding step, the rectangular battery electrode group is produced by winding the pin-shaped jig through the guide hole for each turn.   The method of manufacturing a rectangular battery electrode group according to claim 1, wherein the guide hole is an oval hole having a winding direction as a longitudinal direction.   3. The prismatic battery according to claim 1, wherein an active material of the positive electrode plate contains nickel hydroxide as a main component, and an active material of the negative electrode plate contains a hydrogen storage alloy as a main component. Manufacturing method for electrode group.   3. The prismatic battery according to claim 1, wherein the active material of the positive electrode plate is mainly composed of a lithium-containing metal compound, and the active material of the negative electrode plate is mainly composed of a carbon material. Manufacturing method for electrode group. An electrode group produced by winding a belt-like positive electrode plate and a belt-like negative electrode plate so that a separator is positioned between the positive electrode plate and the negative electrode plate so that the cross section is substantially oval,
Each of the core plate exposed portions in the positive electrode plate and the negative electrode plate is wound while projecting from opposite portions of the both electrode plates to the opposite sides, and at least a part of the guide holes that are coincident with each other when wound are formed. An electrode group for a rectangular battery, wherein the electrode group is formed.

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