JPH0773902A - Activating method for secondary battery - Google Patents

Abstract

PURPOSE:To improve a discharge characteristic under the control of the activation condition of a battery such as high-current discharging or low-temperature discharging by sufficiently activating a secondary battery in a short time through storing the secondary battery for a fixed period at high temperature after the secondary battery is charged. CONSTITUTION:A secondary battery is charged, and then is stored for 7-240 hours (in particular, the degree of 15-72 hours is preferable) at 40-80 deg.C (in particular, 40-70 deg.C are preferable). A nickel-cadmium battery and a nickel-zinc battery, etc., are cited as an applicable secondary battery, and they are suitable, in particular, to activate a nickel-hydrogen battery. Various hydrogen storage alloys can be used as the negative electrode active material, and, in particular, when TiNi alloy containing AB2 Fe is used, this is suitable as negative electrode active material. At that time, a positive electrode, e.g. manufactured by a paste formula by using Ni (OH)2 is used as positive electrode active material, and the hydroxide aqueous solution of alkaline metal such as potassium hydroxide is used as an electrolyte.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for activating a secondary battery, and more particularly to a method for activating a secondary battery which can be sufficiently activated in a short time.

[0002]

2. Description of the Related Art As a conventional method for activating a secondary battery,
The charging / discharging of 150% charging with a charging current of about 0.1 C and discharging to about 0.9 V with a discharging current of about 0.2 C may be repeated several times [eg, electrochemical, 57 , No. 57] . 6
(1989), p. 48], the assembled battery was stored at a high temperature without being charged to activate the battery (for example,
U.S. Pat. No. 4,716,088) was unable to obtain sufficient discharge characteristics (in particular, large current discharge characteristics and low temperature discharge characteristics).

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the problems in the conventional method for activating a secondary battery as described above, and makes it possible to perform sufficient activation in a short time. The purpose is to provide a method of conversion.

[0004]

According to the present invention, a secondary battery is charged and then stored at a high temperature for a certain period so that it can be sufficiently activated in a short time.

As a result, it has become possible to improve discharge characteristics, such as discharge with a large current and discharge at a low temperature, which largely depend on the activated state of the battery.

In the present invention, the temperature during storage is
40-80 degreeC, especially 40-70 degreeC are preferable. That is, when the temperature during storage is lower than 40 ° C., sufficient activation is not performed, and when the temperature is higher than 80 ° C., the melting reaction of the alloy corresponding to the activation proceeds too much, the separator material and the organic material of the sealing part It is not preferable because a decomposition reaction of the material occurs.

As is clear from the above storage temperature, in the present invention, the high temperature during storage means a high temperature within a usable range of the battery, and does not mean a high temperature at which the battery cannot be used. Absent.

The storage time depends on the storage temperature, but is usually 7 to
It is about 240 hours, and particularly preferably about 15 to 72 hours. That is, when the storage time is shorter than 7 hours, sufficient activation cannot be performed, and when the storage time is longer than 240 hours, the residence time in the battery manufacturing process becomes long, resulting in inefficiency.

The present invention can be applied to activation of various secondary batteries. Typical examples of applicable secondary batteries are, for example, a nickel-hydrogen battery, a nickel-cadmium battery, and a nickel-hydrogen battery. The present invention is preferably applicable to activation of nickel-hydrogen batteries, such as zinc batteries.

As the negative electrode active material of the nickel-hydrogen battery, hydrogen storage alloys such as AB ₂ type, AB ₅ type, AB type and A ₂ B type can be used, but the present invention is particularly limited to AB _{2 type.}
Of a secondary battery using a system hydrogen storage alloy [A is Ti, Zr, (Mn), (V), etc., B is V, Ni, Cr, Co, Fe, Mn, etc.] as a negative electrode active material It can be suitably used for conversion.

Examples of the AB ₂ type hydrogen storage alloy include Ti ₁₆ Zr ₁₆ V ₂₂ Ni ₃₉ Cr ₇ and Ti ₁₆ Zr ₁₆ V _22.
Ni ₃₂ Cr ₇ CO ₇ , Ti ₁₅ Zr ₁₅ V _20.6 Ni ₃₀ Cr
_6.6 Co _6.6 Mn _3.6 Al _2.7 , Ti ₁₅ Zr ₁₅ V ₂₁ Ni
₃₁ Cr ₆ Co ₆ Fe ₆ , Ti ₁₅ Zr ₂₁ V ₁₅ Ni ₃₁ Cr ₆
Although Co ₆ Fe _{6 and the} like can be mentioned, the present invention is applicable to, for example, Ti ₁₅ Zr ₁₅ V ₂₁ Ni ₃₁ Cr ₆ Co ₆ Fe ₆ and Ti ₁₅ Z.
T containing Fe such as r ₂₁ V ₁₅ Ni ₃₁ Cr ₆ Co ₆ Fe ₆
It is particularly suitable when an iNi-based hydrogen storage alloy is used.

For the positive electrode of the nickel-hydrogen battery, for example, nickel monoxide (NiO), nickel dioxide (NiO) is used.
A nickel oxide such as O ₂ ), for example, a nickel hydroxide such as nickel hydroxide [Ni (OH) ₂ ] is used as a positive electrode active material, and either a sintering method or a paste method can be used. . However, the above nickel oxide and nickel hydroxide exist when the positive electrode is in a discharged state, and when the positive electrode is in a charged state, they exist as another compound.

An alkaline aqueous solution is used as the electrolytic solution of the nickel-hydrogen battery, and examples of the alkaline aqueous solution include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide. An aqueous solution is used.

[0014]

EXAMPLES Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to only those examples.

Example 1 A negative electrode produced by a sintering method using Ti ₁₅ Zr ₂₁ V ₁₅ Ni ₃₁ Cr ₆ Co ₆ Fe ₆ belonging to the AB ₂ type TiNi type hydrogen storage alloy as a negative electrode active material, and a positive electrode active material. As Ni
Having a positive electrode prepared by a paste method using (OH) ₂ ,
A nickel-hydrogen battery having a nominal capacity of 1100 mAh, which is an aqueous solution prepared by adding 7 g / l of lithium hydroxide to an aqueous solution of potassium hydroxide having a concentration of 30 parts by weight, is used as an electrolytic solution of 0.1 C.
After charging at a rate of 15 hours, it was stored in an environment of 70 ° C. for 72 hours.

Each of the 10 batteries was discharged at a rate of 0.2 C to 1.0 V and the standard capacity was measured.
After charging for 15 hours at the 1C rate, the battery was discharged at the 1C rate and the discharge capacity was measured.

The results are shown in Table 1 below as large current discharge characteristics. In Table 1, the discharge capacity and the utilization rate of the obtained discharge capacity with respect to the standard capacity are shown as the actual efficiency.

Next, 0.1 of each of the 10 batteries is used.
After being charged with C for 15 hours, it was left in an environment of 0 ° C. for 24 hours, discharged at 0 ° C. and a current of 0.5 C rate to 1.0 V, and the discharge capacity was measured.

The results are shown in Table 2 as low temperature discharge characteristics. In addition, in Table 2 as well as the discharge capacity,
The utilization rate of the obtained discharge capacity with respect to the standard capacity is shown as the actual efficiency.

Comparative Example 1 As a negative electrode active material, Ti ₁₅ Zr ₂₁ V ₁₅ N was used as in Example 1.
Using i ₃₁ Cr ₆ Co ₆ Fe ₆ , a nickel-hydrogen battery having a nominal capacity of 1100 mAh was produced in the same manner as in Example 1, and the battery was charged in an environment of 70 ° C. without charging the battery.
Stored for 4 hours. That is, Comparative Example 1 is intended to be activated by the conventional method.

This battery was discharged to 1.0 V at a rate of 0.2 C in the same manner as in Example 1, the standard capacity was measured, and then the battery was charged again at a rate of 0.1 C for 15 hours to give 1 C as in Example 1. The high current discharge characteristics at rate were measured, followed by 0.
After charging at 1C for 15 hours, it was left in an environment of 0 ° C for 24 hours, and discharged at a temperature of 0 ° C at a rate of 0.5C to 1.0V as in Example 1, and the low temperature discharge characteristics were measured. The respective results are shown in Tables 1 and 2.

[0022]

[Table 1]

[0023]

[Table 2]

As shown in Table 1, in Comparative Example 1 in which activation was attempted by the conventional method, only 66.3 to 72.8% of the discharge capacity was obtained with respect to the standard capacity in high current discharge. On the other hand, in Example 1 of the present invention, a discharge capacity of 87.4 to 95.4% was obtained with respect to the standard capacity, and the large current discharge characteristics were excellent.

Further, as shown in Table 2, in Comparative Example 1 in which activation was attempted by the conventional method, only a discharge capacity of 2.3 to 6.8% of the standard capacity was obtained at low temperature discharge. On the other hand, in Example 1 of the present invention, the discharge capacity of 53.0 to 67.2% was obtained with respect to the standard capacity, and the low temperature discharge characteristics were excellent.

Example 2 A nickel-metal hydride battery manufactured in the same manner as in Example 1 was used.
After charging at C rate for 15 hours, it was stored at 45 ° C. for 240 hours.

This battery was measured for high current discharge characteristics at a 1C rate in the same manner as in Example 1 and also for low temperature discharge characteristics at 0 ° C. As a result, performance equivalent to that of Example 1 was obtained.

Example 3 A nickel-hydrogen battery produced in the same manner as in Example 1 was replaced with 0.1
After charging at C rate for 15 hours, it was stored at 60 ° C. for 120 hours.

This battery was measured for high current discharge characteristics at a 1C rate in the same manner as in Example 1 and also for low temperature discharge characteristics at 0 ° C. As a result, performance equivalent to that of Example 1 was obtained.

[0030]

As described above, according to the present invention, after the secondary battery is charged, the secondary battery is stored at a high temperature for a certain period of time, whereby sufficient activation can be performed in a short time. As a result, it has become possible to improve discharge characteristics such as large current discharge characteristics and low temperature discharge characteristics that are affected by the activation state of the battery.

Claims (6)

[Claims] 1. A method of activating a secondary battery, which comprises storing a charged secondary battery at a high temperature to activate the secondary battery in a short time. 2. The method for activating a secondary battery according to claim 1, wherein the secondary battery is a nickel-hydrogen battery. 3. The method for activating a secondary battery according to claim 1, wherein the negative electrode active material is an AB ₂ type hydrogen storage alloy. 4. The AB ₂ type hydrogen storage alloy of the negative electrode active material comprises:
The method for activating a secondary battery according to claim 3, wherein the TiNi-based alloy contains Fe. 5. The method for activating a secondary battery according to claim 1, wherein the storage temperature is 40 to 70 ° C. 6. The method for activating a secondary battery according to claim 1, wherein the storage time is 15 to 72 hours.