JPH05159781A - Nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To improve reliability of a battery without worsening a high rate charge/discharge characteristic of the battery by constituting a surface of a negative pole current collector of copper coated with nickel or titanium. CONSTITUTION:Chargeable/dischargeable negative and positive poles 1, 4 with metal oxide serving as an active material and a nonaqueous electrolyte are provided in a battery, and a surface of its negative pole current collector 3 is constituted of copper coated with nickel or titanium. In the negative pole current collector 3, nickel plating or titanium plating is applied by ordinary electric plating to a copper-made disk of predetermined thickness and diameter. In this way, apprehension of causing deterioration of essential reliability of the battery is not provided at all without melting the negative pole current collector in addition to excellence in a high rate charge/discharge characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery provided with a positive electrode, a negative electrode and a non-aqueous electrolyte, and more particularly to improvement of a negative electrode current collector.

[0002]

2. Description of the Related Art Non-aqueous electrolyte batteries using a positive electrode and a negative electrode using lithium as an active material have been attracting attention for their high energy density and excellent storage characteristics, and active research and development are still being conducted. .. Among them, a non-aqueous electrolyte battery using a carbon material or a metal oxide material for a negative electrode is a promising battery system because it has a high energy density and excellent cycle characteristics.

On the other hand, in this type of battery, metallic copper is used as a negative electrode current collector. This is because copper has a low electric resistance, excellent workability, and does not alloy with lithium.

[0004]

However, in this type of battery, since the dissolution potential in the non-aqueous electrolyte solution is low with respect to lithium, the potential of the negative electrode fluctuates as the battery is charged and discharged, and the potential of 1 to 2 V (vs. Li). However, when the battery is short-circuited or over-discharged, the negative electrode potential may become 3 V (vs. Li) or more, and the metal copper of the negative electrode current collector is dissolved, which causes deterioration of the battery characteristics.

On the other hand, examples of metal materials having a high melting voltage include nickel and titanium, but these materials have a large electric resistance, so that when they are used for the negative electrode current collector, the high rate charge / discharge characteristics of the battery deteriorate.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and carbon which can be charged and discharged,
A negative electrode using a metal oxide as an active material, a positive electrode, and a non-aqueous electrolyte solution, and the surface of the negative electrode current collector is made of nickel or copper coated with titanium.

[0007]

According to the present invention, the reliability of the battery can be improved without deteriorating the high rate charge / discharge characteristics of the battery.

[0008]

EXAMPLES The present invention will be described in detail below with reference to a comparison between examples of the present invention and comparative examples.

(Embodiment 1) FIG. 1 is a half sectional view of a flat type non-aqueous electrolyte secondary battery as one embodiment of the present invention.
Reference numeral 1 is a negative electrode made of a coke material that can be charged and discharged, and is pressure-bonded to a negative electrode current collector 3 fixed to the inner bottom surface of a negative electrode can 2 made of nickel-plated iron. The negative electrode current collector 3
Since it has the main characteristics of the present invention, the details will be described later. 4 is a positive electrode and is 85% by weight of cobalt oxide which is a rechargeable active material, 10% by weight of acetylene black as a conductive agent and 5% by weight of a fluororesin as a binder, and sufficiently mixed and molded. It was done. Then, this was pressure-bonded to a positive electrode current collector 6 also made of aluminum, which was fixed to the inner bottom surface of the positive electrode can 5 made of aluminum.
Reference numeral 7 is a separator made of a polypropylene porous film, in which propylene carbonate is impregnated with an electrolyte solution in which lithium hexafluorophosphate (lithium fluorine Lewis acid) as a lithium salt is dissolved at a rate of 1 mol / l. .. Reference numeral 8 is an insulating packing, and the size of this battery is 24 mm in diameter and 3 mm in height.

The details of the negative electrode current collector 3 will now be described. Nickel plating is applied to the entire circumference of a copper disk having a thickness of 3.0 mm and a diameter of 24 mm by ordinary electroplating. The thickness of the plating layer is about 1 μm. The battery using the nickel-plated negative electrode current collector 3 in this way was designated as Battery A of the present invention.

(Comparative Example 1) A battery was manufactured in the same manner as in Example 1 except that copper was used as the negative electrode current collector 3. This battery was used as a comparative battery X.

(Comparative Example 2) A battery was manufactured in the same manner as in Example 1 except that nickel was used as the negative electrode current collector 3.
This battery was used as a comparative battery Y.

Using these batteries A, X and Y, high rate discharge characteristics were compared. The discharge conditions at this time were a discharge current of 0.5 mA and 5 mA, and a discharge end voltage of 2.0V. The results are shown in FIG. From this, the battery A of the present invention using nickel-plated copper for the negative electrode current collector 3,
Also, it is understood that the comparative battery X using copper has excellent high rate discharge characteristics.

Next, Table 1 shows the internal resistances of the batteries A, X and Y after short-circuiting them for 3 days.

[0015]

[Table 1]

As is clear from Table 1, when both ends of the battery are short-circuited and the battery is over-discharged,
In the comparative battery X using copper as the negative electrode current collector 3, melting occurs due to the low melting voltage of the copper, and as a result, the internal resistance rises and the original reliability of the battery deteriorates.

As described above, the battery A of the present invention using nickel-plated copper for the negative electrode current collector 3 and the comparative battery X using copper are excellent in terms of high-efficiency discharge characteristics. In the above, the battery A of the present invention and the comparative battery Y are superior, and it is understood from the above results that the battery A of the present invention is an excellent battery satisfying both characteristics of high efficiency discharge and reliability.

In the battery A of the present invention described above,
Although the negative electrode current collector 3 having nickel plated on the surface of copper was used, the same result was obtained with titanium other than nickel.
In addition to electroplating, electroless plating may be used as a plating method, and a method of coating the copper surface using a method such as vapor deposition or coating is effective.

Besides the rechargeable coke, pyrolytic carbon, graphite, iron oxide, niobium oxide, tungsten oxide, etc. can be used as the negative electrode 1.

Furthermore, even if nickel oxide or manganese oxide is used as the positive electrode 4, the same performance as that of cobalt oxide is exhibited.

[0021]

As is apparent from the above description, the present invention comprises a negative electrode using chargeable / dischargeable carbon or a metal oxide as an active material, a positive electrode, and a non-aqueous electrolyte solution. Since the surface of nickel is used as the current collector of nickel or copper coated with titanium is used, it is excellent in high-rate discharge characteristics, and the original reliability of the battery decreases without the negative electrode current collector melting. There is no fear of coming.

[Brief description of drawings]

FIG. 1 is a sectional view of a battery of the present invention.

FIG. 2 is a high rate discharge characteristic diagram of a battery of the present invention and a comparative battery.

[Explanation of symbols]

 1 Negative electrode 3 Negative electrode current collector 4 Positive electrode A Battery of the present invention X, Y Comparative battery

Front page continuation (72) Inventor Hiroshi Watanabe 2-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Ryuji Oshita 2-18-2 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. Within

Claims (1)

[Claims] 1. A chargeable / dischargeable carbon or negative electrode using a metal oxide as an active material, a positive electrode, and a non-aqueous electrolyte solution. The surface of the negative electrode is nickel or a negative electrode current collector. A non-aqueous electrolyte battery characterized by using copper coated with titanium.