JPH11167929A - Square battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery having electrode group terminal connecting structure which is suitable for mass production and capable of increasing energy density, and provide a square battery at low cost. SOLUTION: In this square battery 1, the center line of the winding axis of an electrode group 2 wound flat is parallel to the opening surface of a square battery case 6, and the flat part of the electrode group 2 and the opening surface of the battery case 6 are positioned at right angles, the winding end of the electrode group 2 is positioned on the opening surface side, and the case 6 and a case 7 are connected through welding. At least part of the current collector 11 of a positive electrode positioned on the outermost side of the electrode group 2 is welded together with the case 6 and the case 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a prismatic battery.

[0002]

2. Description of the Related Art Conventionally, in the case of a rectangular cylindrical battery using an elliptical spiral electrode group, the elliptical spiral electrode group is arranged such that the winding axis of the spiral electrode group and the opening surface of the battery case are at right angles. Had been inserted.

However, in the case of this structure, when the electrode group is inserted, the edge of the end face of the electrode often comes in contact with the edge of the opening face of the battery case, turns off, the active material falls off, the electrode base material is bent, and the separator is bent. And the internal short circuit was caused.

Further, in order to minimize the above-mentioned inconvenience, it is necessary to make the thickness of the elliptical spiral electrode group 90% or less of the dimension of the opening surface. No density was obtained.

In order to solve such a problem, a center line of a flat wound electrode group winding axis is parallel to a rectangular battery case opening surface, and a plane portion of the electrode group and a battery case opening surface are aligned. Have been proposed to be inserted at right angles. (Hereinafter, it will be referred to as a flat-wound battery.) By the way, in a conventional battery (hereinafter, referred to as an elliptical spiral battery) in which an elliptical spiral electrode group is inserted so that its winding axis is perpendicular to the case opening surface. When an aluminum case metal case is used, the case serves as a positive electrode terminal, and the convex terminal provided on the case lid serves as a negative electrode terminal. In the electrical connection between these terminals and the electrodes, in the electrical connection of the positive electrode, the outermost electrode of the electrode is used as the positive electrode, an active material paste uncoated region is provided at the positive electrode end portion, and the current collector and the inner surface of the battery case are connected. Are connected by the contact of In addition, in order to further stabilize the internal resistance, a band-shaped aluminum plate is welded to a part of the uncollected aluminum current collector, and the lead and lid attached are spot-welded, or the lead is attached to the battery case and case lid. And connected by welding. Alternatively, a downward U-shaped slit is inserted in the corresponding portion, the current collector is bent into a rectangular lead, and the lead is raised in the direction of the case opening surface to spot-weld the lead and the lid, or the lead is connected to the battery. Connected by welding between the case and case lid.

On the other hand, in the electrical connection of the negative electrode, an area where the negative electrode mixture layer of the negative electrode current collector is not applied is provided at the center of the winding shaft, and a rectangular lead is attached by spot welding, or similarly to the positive electrode lead. Leads are provided by slit processing,
The lead is raised and connected to the negative terminal of the case lid.

[0007]

In the conventional elliptical spiral battery, welding of the lead to the electrode or cutting out and bending of the lead and attaching the lead to the terminal are essential steps as described above. I have. These steps are important parts for extracting energy to the outside in order to function as a battery, and are very important steps. However, these steps, on the other hand, are very complicated steps, and are unavoidable steps in mass production of batteries.

Further, when the lead is cut out, in a conventional battery in which the center line of the flat wound electrode group winding axis is perpendicular to the opening of the rectangular battery case, the lead is welded to the electrode as described above. Alternatively, when an electrode is cut out to form a bent lead, a space for welding or processing the lead in the thickness direction of the electrode group is required. Therefore, the amount of the active material to be filled is reduced, and as a result, the energy density of the battery is reduced.

Further, as the outer shape of the battery becomes smaller due to the progress of technology, the electrode plate becomes thinner and smaller, so that lead mounting such as lead mounting, lead cutting and bending, and the like become more complicated. This not only hinders mass production, but also increases costs.

Accordingly, the present invention has been made to solve the above-mentioned problem, and an object of the present invention is to mass-produce without a complicated lead processing and mounting process to an electrode plate as in the prior art. Another object of the present invention is to provide a battery having a terminal connection structure for an electrode group that is suitable for integration and can improve the energy density, and to provide an inexpensive battery.

[0011]

In order to achieve the above-mentioned object, the present invention is directed to a flat-wound electrode group winding axis in which the center line is parallel to the opening of the rectangular battery case, and the plane of the electrode group is flat. The battery is inserted so that the portion and the opening surface of the battery case are positioned at a right angle, and the winding end of the electrode group is positioned on the case opening surface side, and the case and the case lid are welded and connected. And a current collector for the electrode located on the outermost side of the electrode group, wherein at least a part of the current collector is welded together with the case and the case lid.

A second invention according to the first invention is characterized in that the case and the case lid are made of aluminum or an aluminum alloy, the electrode located outside the electrode group is a positive electrode, and the positive electrode current collector is It is characterized by being aluminum or an aluminum alloy.

A third invention according to the first invention is characterized in that the case and the case lid are made of iron-nickel plated steel or stainless steel, the outermost electrode of the electrode group is a negative electrode, and the negative electrode It is characterized in that the electric body is copper.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below.

FIG. 1 is an explanatory longitudinal sectional view showing one embodiment of the present invention, and is an example applied to a prismatic nonaqueous electrolyte secondary battery.

In the figure, 1 is a non-aqueous electrolyte secondary battery, 2
Denotes an electrode group, 3 denotes a positive electrode, 4 denotes a negative electrode, 5 denotes a separator, 6 denotes a battery case also serving as a positive electrode terminal having an inner dimension of 8 mm × 34 mm × 48 mm, and 7 denotes a case lid.

11 is a positive electrode lead, 13 is a negative electrode lead, 1
Reference numeral 4 denotes a negative electrode terminal, 15 denotes a negative electrode lead connection body, and 8 denotes an electrolyte injection hole sealing plug (not shown).

The positive electrode plate 3 was manufactured as follows. 86 parts by weight of LiCoO ₂ having an average particle diameter of 6 μm, 5 parts by weight of acetylene black as a conductive agent, and 9 parts by weight of polyvinylidene fluoride as a binder are mixed, and N-methyl-2-pyrrolidone is added as appropriate. And applied to both sides of an aluminum foil having a thickness of 20 μm to a thickness of 100 μm on one side, followed by drying and rolling. Then, by cutting, a strip-shaped positive electrode plate 3 having a thickness of 0.16 mm and a width of 30 mm was produced. However, the outermost and outermost electrode group 2
Only 95 mm corresponding to the end portion was a single-side coated portion, and only 10 mm of the front end was a non-coated portion on both sides.
This uncoated portion also serves as the positive electrode lead 11.

The negative electrode plate 4 was manufactured as follows. Scale-like artificial graphite (LONZAKS25) with an average particle size of 25 μm and an average particle size of 2
1: 3 by weight ratio with 0 μm spheroidal graphite (MCMB made by Osaka Gas)
86 parts by weight of the graphite mixture and 14 parts of polyvinylidene fluoride as a binder were mixed, N-methyl-2-pyrrolidone was appropriately added to form a paste, and a copper plate having a thickness of 14 μm was formed to a thickness of 100 μm on one side. After being coated on both sides, it was dried and rolled. Then, the thickness is reduced to 0.
A strip-shaped negative electrode plate 4 having a width of 22 mm and a width of 31 mm was produced.
However, only 95 mm corresponding to the inner surface of the battery case 6 corresponding to the outermost periphery of the electrode group 2 was an uncoated portion on one side, and only 10 mm corresponding to the tip portion was an uncoated portion on both surfaces. This uncoated portion also serves as the negative electrode lead 13.

The separator 5 has a thickness of 25 μm and a width of 33 μm.
mm, a porosity of 40%, an average through-hole diameter of 0.01 μm, and a breaking strength of 0.7 kg. Then, the positive electrode plate 3 and the negative electrode plate 4 were flatly wound with the separator 5 interposed therebetween, thereby producing an electrode group 2.

The configuration of the nonaqueous electrolyte battery 1 is such that the electrode group 2 in which the positive electrode plate 3 and the negative electrode plate 4 are wound flat through the separator 5 has the center axis of the winding shaft as shown in FIG. 0.3m thickness
The battery case 6 was inserted into the battery case 6 in a direction parallel to the opening of the square aluminum battery case 6 and at a right angle to the plane portion 20 of the electrode group 2 and the opening of the battery case 6.

Next, the negative electrode terminal collector 13 (negative electrode lead 13) located on the outermost periphery is connected to the negative electrode lead connector 15 on the back of the case lid by needle caulking, while the outermost electrode terminal terminal is provided. The case 6 and the case lid 7 were fitted together while sandwiching the current collector 11 (positive lead 11) of the positive electrode between the battery case 6 and the case lid 7. At this time, a portion of the positive electrode current collector 11 at the tip of 5 mm is outside the case. Next, Case 6
And case lid 7, and case 6, current collector 11 and case lid 7
Was sealed with a YAG laser in which a continuous wave and a pulse wave were synthesized. As a result, the positive electrode lead 11 and the case also serving as the positive electrode terminal were electrically connected. Also, a portion of the current collector 11 at the tip of 5 mm, which was outside the case, was cut at the time of laser welding and separated from the battery. (FIG. 4
Next, 1M LiPF ₆ / ethylene carbonate (EC)
A predetermined amount of electrolyte solution of + diethyl carbonate (DEC) (1: 1) was injected under vacuum and sealed.

[Conventional Example] FIG. 2 is an exploded explanatory view showing a conventional example, and is an example applied to a prismatic nonaqueous electrolyte secondary battery.

In the figure, 1 is a non-aqueous electrolyte secondary battery, 2
Is an electrode group, 3 is a positive electrode (not shown), 4 is a negative electrode (not shown), 5 is a separator (not shown), and 6 is an inner dimension of 8 mm ×
Battery case also serving as 34 mm x 48 mm positive terminal, 7
Is a case lid.

11 is a positive electrode lead, 13 is a negative electrode lead, 1
Reference numeral 4 denotes a negative electrode terminal, 15 denotes a negative electrode lead connection body, and 8 denotes an electrolyte injection hole sealing plug (not shown).

The positive electrode plate 3 was manufactured as follows. 86 parts by weight of LiCoO ₂ having an average particle diameter of 6 μm, 5 parts by weight of acetylene black as a conductive agent, and 9 parts by weight of polyvinylidene fluoride as a binder are mixed, and N-methyl-2-pyrrolidone is added as appropriate. And applied to both sides of an aluminum foil having a thickness of 20 μm to a thickness of 100 μm on one side, followed by drying and rolling. Then, by cutting, a strip-shaped positive electrode plate 3 having a thickness of 0.16 mm and a width of 39 mm was produced.

However, only 70 mm facing the inner surface of the battery case 6 corresponding to the outermost periphery of the electrode group 2 was an uncoated portion 30 on one side, and the 20 mm of the leading end processed portion was an uncoated portion on both sides.

The negative electrode plate 4 was manufactured as follows. Scale-like artificial graphite (LONZAKS25) with an average particle size of 25 μm and an average particle size of 2
1: 3 by weight ratio with 0 μm spheroidal graphite (MCMB made by Osaka Gas)
86 parts by weight of the graphite mixture and 14 parts of polyvinylidene fluoride as a binder were mixed, and N-methyl-2-pyrrolidone was appropriately added to form a paste, and a 14 μm-thick copper plate having a thickness on one side of 100 μm was obtained. After being coated on both sides, it was dried and rolled. Then, the thickness is reduced to 0.
A belt-shaped negative electrode plate 4 having a width of 22 mm and a width of 40 mm was produced. However, the winding start portion 10 located at the center of the electrode group 2
mm was the uncoated portion 31 on one side. (See FIG. 3) Next, the uncoated portions of both sides of the positive electrode 3 were 20 mm long × 10 m wide.
A downward U-shaped slit was provided in parallel with the winding axis of m, and the rectangular upper portion was turned back to form a rectangular positive electrode lead.

Next, 50 mm × 50 mm
A lead made of a 3 mm wide nickel foil was attached by spot welding.

The separator 5 has a thickness of 25 μm and a width of 42 μm.
mm, a porosity of 40%, an average through-hole diameter of 0.01 μm, and a breaking strength of 0.7 kg.

Then, the positive electrode plate 3 and the negative electrode plate 4 were wound in an elliptical spiral shape with the separator 5 interposed therebetween, whereby an electrode group 2 was produced.

The structure of the nonaqueous electrolyte battery 1 is the same as that of the electrode group 2
Was inserted into the battery case 6 such that the center line of the winding shaft was perpendicular to the opening surface of the aluminum prismatic battery case 6 having a thickness of 0.3 mm as shown in FIG.

Next, the negative electrode lead 13 is connected to the negative electrode lead connector 15 on the back of the case lid by spot welding, and the case 6 and the case lid 7 are held while the positive electrode lead 11 is sandwiched between the battery case 6 and the case lid 7. Mated. Next, the joints between the case 6 and the case lid 7 and between the case 6 and the current collector 11 and the case lid 7 were welded and sealed by laser. As a result, the positive electrode current collector 11 and the case also serving as the positive electrode terminal were electrically connected.

Next, a predetermined amount of an electrolyte of 1M LiPF ₆ / ethylene carbonate (EC) + diethyl carbonate (DEC) (1: 1) was injected in a predetermined amount from the injection hole and sealed.

Next, each battery was set to 1 CmA 4.1 V
, And discharged at 0.5 CmA until the terminal voltage reached 2.7 V to determine the discharge capacity.
As a result, the battery according to the present invention and the conventional battery had a discharge capacity of 900 mAh, whereas the conventional battery had a discharge capacity of 850 mAh.

That is, it was found that the energy density of the battery of the present invention was improved even though the battery volume was the same as that of the conventional battery.

In addition, the flat wound electrode group 2 is set so that its central axis is parallel to the opening surface of the battery case 6 and the electrode group 2
The current collectors of the positive electrode and the negative electrode also serve as leads, and the current collector, which is the lead of one of the electrodes together with the sealing of the case and the case lid, is inserted so that the flat part is perpendicular to the opening surface. By combining the configurations of connecting the bodies, the lead processing and the step of attaching the lead to the electrode plate can be eliminated from the conventional process.

Further, conventionally, both the positive electrode and the negative electrode had to be connected to the terminals, respectively. However, since the connection between the lead (current collector) of one electrode and the terminal is performed together with the sealing, the connection is made. The complicated steps are eliminated, and further mass production becomes possible. Therefore, an inexpensive, small, and lightweight battery can be provided.

In the above embodiments, the prismatic non-aqueous electrolyte secondary battery has been described. However, the present invention is not limited to this. The prismatic lithium primary battery, the prismatic nickel cadmium secondary battery, the prismatic nickel zinc secondary battery, the prismatic nickel It goes without saying that the same effect can be obtained in a rectangular battery such as a hydrogen secondary battery employing a flat spiral electrode group.

In the present invention, in the case of a non-aqueous electrolyte secondary battery, a host having a large capacity is used as the host material of the negative electrode. By applying the present invention, the non-aqueous electrolyte secondary A secondary battery can also be provided. For example, amorphous carbon, SnO, S
nO ₂ , Sn _1-x M _x O (M = Hg, P, B, Si, Ge
Or Sb, provided that 0 ≦ X <1), Sn _1-x M _x O ₂ (M =
Hg, P, B, Si, Ge or Sb, provided that 0 ≦ X <
_{1), Sn 3 O 2 (} OH) 2, Sn 3-x M x O 2 (OH)
₂ (M = Mg, P, B, Si, Ge, Sb, As or M
n, where 0 ≦ X <3), LiSiO ₂ , SiO ₂ , Si
O, SiO _2-x (0 ≦ X <1), Si _1-x M _x O (M = H
g, P, B, Si, Ge or Sb, provided that 0 ≦ X <
1), Si _1-x M _x O ₂ (M = Hg, P, B, Si, Ge or Sb, where 0 ≦ X <1), Si _1-x M _x O _{2 -y} (M = H
g, P, B, Si, Ge or Sb, provided that 0 ≦ X <1,
0 ≦ y <1) or one or more selected from LiSnO _2. Further, in a non-aqueous electrolyte secondary battery, the positive electrode, the negative electrode, the separator, the non-aqueous electrolyte, A combination of a positive electrode, a negative electrode, an organic or inorganic solid electrolyte as a separator and a non-aqueous electrolyte,
Or a positive electrode, a negative electrode, a separator, may be a combination with an organic or inorganic solid electrolyte and a non-aqueous electrolyte,
It is not particularly limited. In addition, the separator means an inorganic solid powder or the like settled by a separator or an organic binder, and any known one can be used. It goes without saying that a known non-aqueous electrolyte can also be used. In addition, a configuration in which an organic solid electrolyte (particularly, PAN, PEO, or the like) is formed on the upper surface of the positive electrode mixture layer and / or the negative electrode mixture layer may be employed.

[0041]

As described above, the prismatic battery of the present invention has the following features.
Inserting the flat electrode group so that its central axis is parallel to the opening surface of the battery case, and the plane part of the electrode group is parallel to the opening surface; , And connecting the current collector, which is the lead of one of the electrodes, together with the case and the lid of the case lid, completely eliminates the lead processing and the step of attaching the lead to the electrode plate from the conventional process. be able to.

In addition, conventionally, both the positive and negative leads had to be connected to the terminals, respectively.
Since the connection between the lead (current collector) of one electrode and the terminal is performed together with the sealing, complicated steps are eliminated, and further mass production becomes possible.

Therefore, it is possible to provide an inexpensive, small, and lightweight prismatic battery. Moreover, the energy density can be improved without changing the external dimensions of the prismatic battery.

The industrial value of the present invention is extremely large.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a prismatic battery according to the present invention.

FIG. 2 is an exploded explanatory view showing an embodiment of a conventional prismatic battery.

FIG. 3 is an explanatory diagram of a negative electrode according to one embodiment of a conventional prismatic battery.

FIG. 4 is an enlarged explanatory view of an end portion showing one embodiment of a prismatic battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte secondary battery 2 Electrode group 3 Positive electrode 4 Negative electrode 5 Separator 6 Battery case 7 Battery cover 8 Electrolyte injection hole sealing plug 11 Positive electrode lead 12 Positive electrode terminal 13 Negative electrode lead 14 Negative electrode terminal 15 Negative electrode lead connection body

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01M 10/40 H01M 10/40 Z

Claims (3)

[Claims] An electrode group is wound so that the center line of a flatly wound electrode group winding axis is parallel to a rectangular battery case opening surface, and a plane portion of the electrode group and the battery case opening surface are positioned at right angles. In a prismatic battery in which a group winding end is inserted so as to be located on a case opening surface side and the case and the case lid are connected by welding, a current collector of an electrode located on an outermost electrode group, A prismatic battery wherein at least a part thereof is welded together with the case and the case lid. 2. The method according to claim 1, wherein the case and the case lid are made of aluminum or an aluminum alloy, the electrode located on the outermost side of the electrode group is a positive electrode, and the positive electrode current collector is aluminum or an aluminum alloy. Claim 1
The prismatic battery as described. 3. The method according to claim 1, wherein the case and the case lid are made of iron-nickel-plated steel or stainless steel, the outermost electrode of the electrode group is a negative electrode, and the negative electrode current collector is copper. The prismatic battery according to claim 1.