JP2003109672A - Method of charging nonaqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance quick charging. SOLUTION: This method of charging a nonaqueous electrolyte battery provided with a positive electrode comprising a positive electrode active material capable of doping and dedoping lithium, a negative electrode comprising a negative electrode active material capable of doping and dedoping lithium, and a nonaqueous electrolyte interposed between the positive electrode and negative electrode, includes a first charging to carry out constant current charging with the charging current value IA in a range of 0.2 CmA-0.4 CmA of the rated capacity, and a second charging to carry out constant current charging with the charging current value IB in a range of 0.4 CmA-0.6 CmA of the rated capacity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for charging a non-aqueous electrolyte secondary battery.

[0002]

2. Description of the Related Art In recent years, with the widespread use of portable devices such as mobile phones and notebook computers and cordless devices, there is an increasing demand for batteries as a power source. In particular, it is required to develop a secondary battery that is small and lightweight, has a high energy density, and can be repeatedly charged and discharged. As such a battery, research and development of a non-aqueous electrolyte secondary battery, in particular, a lithium ion secondary battery using a lithium-containing composite oxide such as cobalt lithium for the positive electrode and a carbon material for the negative electrode has been actively conducted.

As a method of charging a non-aqueous electrolyte secondary battery such as such a lithium ion secondary battery, a method has been developed in which charging is performed with a constant current up to a predetermined voltage and then constant voltage charging is performed with a set voltage. There is.

[0004]

On the other hand, the demand for rapid charging of the driving power source is increasing with the portable equipment.

As a method of charging the non-aqueous electrolyte secondary battery, a rapid charging method in which the charging current value is set to a high value in the constant current charging section and charging is performed can be considered in order to shorten the charging time while keeping the above charging method.

However, the rapid charging by the high charging current has a problem that the rapid charging property is not improved because the battery performance is remarkably deteriorated in, for example, a lithium ion battery.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and an object thereof is to provide a method for charging a non-aqueous electrolyte with improved rapid chargeability.

[0008]

A method for charging a non-aqueous electrolyte battery according to the present invention comprises a positive electrode containing a positive electrode active material capable of doping and dedoping lithium, and a negative electrode active material capable of doping and dedoping lithium. A method for charging a non-aqueous electrolyte battery comprising a negative electrode containing the non-aqueous electrolyte interposed between the positive electrode and the negative electrode, wherein a rated capacity of 0.2 CmA to
After the first charging in which constant current charging is performed with the charging current value I _A in the range of 0.4 CmA, and the charging current value I _B in the range of 0.4 CmA to 0.6 CmA of the rated capacity after the first charging. Constant current charging and second charging are provided.

In the charging method for a non-aqueous electrolyte battery according to the present invention as described above, the constant current charging section is divided, and the optimum charging current value and charging time are selected in each section to impair the battery characteristics. Without charging time.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Specific embodiments of the present invention will be described below.

FIG. 1 is a vertical cross-sectional view showing one structural example of the non-aqueous electrolyte battery of the present invention. In this non-aqueous electrolyte battery 1, a layered body in which a film-shaped positive electrode 2 and a film-shaped negative electrode 3 are wound in close contact with each other with a separator 4 in between is loaded inside a battery can 5. .

The positive electrode 2 is produced by applying a positive electrode mixture containing a positive electrode active material and a binder onto a current collector and drying it. A metal foil such as an aluminum foil is used for the current collector.

As the positive electrode active material, a metal oxide, a metal sulfide or a specific polymer can be used depending on the type of the intended battery.

For example, when forming a lithium primary battery
If the positive electrode active material is TiS,_Two, MnO_Two,graphite,
FeS_TwoEtc. can be used. Also, lithium
When configuring a secondary battery, the positive electrode active material is Ti
S_Two, MoS_Two, NbSe_Two, V_TwoO₅Metal sulfide such as
Alternatively, oxides can be used. Also, Li_x
MO _Two(In the formula, M represents one or more transition metals, and x represents a battery.
It depends on the charging / discharging state, and is usually 0.05 or more, 1.
It is 10 or less. ) -Based lithium composite oxides, etc.
Can be used. This lithium composite oxide is
The transition metal M formed is preferably Co, Ni, Mn, or the like.
Good Specific examples of such a lithium composite oxide include
LiCoO_Two, LiNiO_Two, LiNi_yCo_1-yO
_Two(In the formula, 0 <y <1.), LiMn_TwoO_FourEtc.
Can be mentioned. These lithium composite oxides are
Positive electrode active material that can generate high voltage and has excellent energy density
Become quality. For the positive electrode 2, plural kinds of these positive electrode active materials are used.
You may use together.

As the binder of the above positive electrode mixture, a known binder which is usually used in a positive electrode mixture of a battery can be used, and a conductive agent or the like is also known in the above positive electrode mixture. Additives can be added.

The negative electrode 3 is produced by applying a negative electrode mixture containing a negative electrode active material and a binder onto a current collector and drying it. For the current collector, a metal foil such as a copper foil is used.

When constructing a lithium primary battery or a lithium secondary battery, it is preferable to use lithium, a lithium alloy, or a material capable of doping and dedoping lithium as the negative electrode material. As a material that can be doped or dedoped with lithium, for example, a carbon material such as a non-graphitizable carbon-based material or a graphite-based material can be used. Specifically, carbon materials such as pyrolytic carbons, cokes, graphites, glassy carbon fibers, organic polymer compound fired bodies, carbon fibers, and activated carbon can be used. Examples of the above cokes include pitch coke, nice coke, petroleum coke, and the like. Further, the above-mentioned organic polymer compound fired body refers to one obtained by firing a phenol resin, a furan resin or the like at an appropriate temperature to carbonize.

In addition to the above-mentioned carbon material, a polymer such as polyacetylene or polypyrrole or an oxide such as SnO ₂ can be used as a material that can be doped or dedoped with lithium. Further, as the lithium alloy, a lithium-aluminum alloy or the like can be used.

As the binder for the above-mentioned negative electrode mixture, a known binder which is usually used for a negative electrode mixture for lithium ion batteries can be used, and also a known additive for the above-mentioned negative electrode mixture. Etc. can be added.

The non-aqueous electrolytic solution is prepared by dissolving an electrolyte in a non-aqueous solvent.

As the electrolyte, it is possible to use a known electrolyte that is usually used in a battery electrolyte. For example, LiClO ₄ , LiAsF ₆ , LiP
_{F 6, LiBF 4, LiB (} C 6 H 5) 4, CH 3 SO
₃ Li, CF ₃ SO ₃ Li, LiCl, LiBr and the like. Further, as the non-aqueous solvent, various non-aqueous solvents conventionally used for non-aqueous electrolytic solutions can be used.
For example, propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 2
-Methyltetrahydrofuran, 1,3-dioxolane,
4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile,
Examples include propionitrile, anisole, acetic acid ester, butyric acid ester, propionic acid ester and the like.

And, such a non-aqueous electrolyte battery 1 is
It is manufactured as follows.

For the positive electrode 2, a positive electrode mixture containing a positive electrode active material and a binder is uniformly applied onto a metal foil such as an aluminum foil, which is a positive electrode current collector, and dried to form a positive electrode active material layer. It is produced by forming. As the binder of the positive electrode mixture, a known binder can be used, and a known additive or the like can be added to the positive electrode mixture.

For the negative electrode 3, a negative electrode mixture containing a negative electrode active material and a binder is uniformly applied onto a metal foil such as a copper foil which is a negative electrode current collector and dried to form a negative electrode active material layer. It is produced by forming. As the binder for the negative electrode mixture, a known binder can be used, and a known additive or the like can be added to the negative electrode mixture.

The positive electrode 2 and the negative electrode 3 obtained as described above are brought into close contact with each other via a separator 4 made of, for example, a microporous polypropylene film, and wound in a spiral shape many times to form a wound layer body. To be done.

Next, the insulating plate 6 is inserted into the bottom of the iron-made battery can 5 having nickel plated inside, and the wound layer body is further housed. Then, in order to collect current from the negative electrode, one end of a negative electrode lead 7 made of nickel, for example, is pressed onto the negative electrode 3 and the other end is welded to the battery can 5. This allows the battery can 5
Becomes conductive with the negative electrode 3 and becomes an external negative electrode of the non-aqueous electrolyte battery 1. Further, in order to collect current from the positive electrode 2, one end of a positive electrode lead 8 made of, for example, aluminum is attached to the positive electrode 2
Attached to the battery lid 1 at the other end through a thin plate 9 for cutting off the current.
It is electrically connected to 0. The thin plate 9 for cutting off current cuts off current according to the internal pressure of the battery. This allows
The battery lid 10 is electrically connected to the positive electrode 2 and serves as an external positive electrode of the non-aqueous electrolyte battery 1.

Next, a non-aqueous electrolytic solution is injected into the battery can 5. This non-aqueous electrolytic solution is prepared by dissolving an electrolyte in a non-aqueous solvent.

Next, the battery lid 5 is fixed by caulking the battery can 5 via the insulating sealing gasket 11 coated with asphalt, and the cylindrical non-aqueous electrolyte battery 1 is manufactured.

In this non-aqueous electrolyte battery 1,
As shown in FIG. 1, a center pin 12 connected to the negative electrode lead 7 and the positive electrode lead 8 is provided, and a safety valve device for venting internal gas when the internal pressure of the battery becomes higher than a predetermined value. 13 and a PTC element 14 for preventing a temperature rise inside the battery.

Then, the battery manufactured as described above is charged, and during charging, the present invention prevents the deterioration of the battery performance and shortens the charging time by dividing the constant current charging section. It proposes a charging method to be performed.

A charging method for the initial charging of the above non-aqueous electrolyte secondary battery, here a lithium ion secondary battery, will be described with reference to FIG. FIG. 2 shows changes in the charging voltage and current with respect to time for the initial charging of the lithium-ion secondary battery, with the charging voltage and charging current as the vertical axis and the time axis as the horizontal axis.

First, in the first charging, as shown in FIG. 2, constant current charging is performed for a predetermined charging time t _A at a predetermined charging current value I _A. The charging current value I _A is 0.2 CmA to 0.
The current value is equivalent to the range of 4 CmA. When the first charging current value I _A is lower than 0.2 CmA, it is necessary to increase the second charging current value I _B in order to shorten the charging time. Then, if the second charging current value I _B is increased, the capacity may be reduced or lithium may be deposited on the electrodes. Further, when higher than 0.4CmA the _{I A,} the capacity is lowered. The charging current value I _A is 0.2 CmA to 0.
By setting the range to 4 CmA, it is possible to shorten the charging time without causing a capacity decrease or lithium deposition.

The charging time t _A is set in advance so that 40% to 75% of the rated capacity is charged in the first charging with the charging current value I _A. Charging time t _A is 40%
In the following cases, it is necessary to increase the second charging current value I _B in order to shorten the charging time. Then, when the second charging current value I _B is increased, there arises a problem that the capacity is reduced or lithium is deposited on the electrode. If the charging time t _A is higher than 75%, the charging time cannot be shortened. Charge time t _A is 40% of the rated capacity
By setting the charging time to 75%, it is possible to shorten the charging time without causing a capacity decrease or lithium deposition.

Next, in the second charging, first the charging current value
I_BConstant current charging at. And the preset voltage value
V₁When it reaches, switch to constant voltage charging. Charging
Flow value I_BIs a voltage equivalent to 0.4 CmA to 0.6 CmA.
Let it be the current price. Charging current value I_BIs lower than 0.4 CmA
In that case, the charging time cannot be shortened. Also, I _B
Is higher than 0.6 CmA, the lithium on the electrode
Will be deposited. Charging current value I_B0.4 CmA ~
By setting the range to 0.6 CmA, lithium precipitation occurs.
The charging time can be shortened without doing so. In addition,
Electricity time t_BIs the remaining battery capacity due to the first charge,
When the capacity equivalent to 25% to 60% of the rated capacity can be charged
In between.

Here, in the present invention, the first charging current value I
_A is set to be lower than the second charging current value I _B.
By setting the first charging current value I _A lower than the second charging current value I _B, it is possible to prevent deterioration of the battery characteristics. It has been confirmed by experiments that the capacity decreases by about 3% when the charging current value I _A is set higher than I _B.

That is, the present invention prevents the deterioration of the battery characteristics by lowering the charging current value in the first charging than the charging value in the second charging and the charging current after the second charging. An excellent charging method that shortens the charging time by increasing the value is provided.

As described above, in the present invention, by dividing the constant current charging section having an influence on the charging time and selecting the optimum charging current value and charging time in each section, the battery characteristics are not impaired. The charging time can be shortened.

In the above-described embodiment, the case where the non-aqueous electrolyte battery is charged in two steps has been described as an example, but the present invention is not limited to this and multi-step of two or more steps. It can also be applied when charging a non-aqueous electrolyte battery. In that case, the first charging current value I
_A may be set lower than the charging current value I _C after the second stage. By setting the first charging current value I _A lower than the charging current value I _C after the second stage, it is possible to prevent the deterioration of the battery characteristics.

Further, in the above-described embodiment, the non-aqueous electrolyte battery using the non-aqueous electrolyte in which the electrolyte salt is dissolved in the non-aqueous solvent has been described as the non-aqueous electrolyte. Is not limited to this, a solid electrolyte battery using a solid electrolyte containing an electrolyte salt, a gel electrolyte battery using a gel electrolyte impregnated with a non-aqueous solvent and an electrolyte salt in an organic polymer Any of these can be applied.

As the above-mentioned solid electrolyte, both inorganic solid electrolytes and polymer solid electrolytes can be used as long as they are materials having lithium ion conductivity. Examples of the inorganic solid electrolyte include lithium nitride and lithium iodide.
The solid polymer electrolyte is composed of an electrolyte salt and a polymer compound that dissolves the electrolyte salt, and the polymer compound is an ether polymer such as poly (ethylene oxide) or its cross-linked product, a poly (methacrylate) ester system, or an acrylate system. They can be used alone, or can be copolymerized or mixed in the molecule.

As the matrix of the gel electrolyte, various polymers can be used as long as they absorb the non-aqueous electrolyte and gel. For example, fluorine-based polymers such as poly (vinylidene fluoride) and poly (vinylidene fluoride-co-hexafluoropropylene), ether-based polymers such as poly (ethylene oxide) and its cross-linked products, and poly (acrylonitrile), etc. Can be used. In particular, it is desirable to use a fluoropolymer because of its redox stability. Ionic conductivity is imparted by containing an electrolyte salt.

Further, in the above-mentioned embodiment, the cylindrical secondary battery has been described as an example, but the battery to which the present invention is applied is not limited to this, and the battery having a rectangular shape or the like is used. It is also applicable to batteries and batteries of various sizes such as large size.

[0043]

EXAMPLES Next, Examples and Comparative Examples conducted to confirm the effects of the present invention will be described. It should be noted that, in the examples shown below, specific compounds, numerical values, and the like are described, but it goes without saying that the present invention is not limited to these.

First, a sample non-aqueous electrolyte battery was prepared as follows.

First, a negative electrode was prepared as follows.
90 parts by weight of graphite as a negative electrode active material and 10 parts by weight of polyvinylidene fluoride as a binder were mixed to prepare a negative electrode mixture. Next, the negative electrode mixture was dispersed in N-methyl-2-pyrrolidone (NMP) to form a slurry. Then, this slurry is uniformly applied to both sides of a strip-shaped copper foil having a thickness of 10 μm, which is a negative electrode current collector, and dried to form a negative electrode active material layer, followed by compression molding with a roll press machine to prepare a negative electrode. did.

Next, a positive electrode was prepared as follows. A positive electrode mixture was prepared by mixing 85 parts by weight of LiCoO ₂ as a positive electrode active material, 5 parts by weight of scaly graphite as a conductive agent, and 10 parts by weight of polyvinylidene fluoride as a binder.

Next, the positive electrode mixture was dispersed in N-methyl-2-pyrrolidone (NMP) to form a slurry. Then, this slurry was uniformly applied on both sides of an aluminum foil having a thickness of 20 μm to be a positive electrode current collector, dried to form a positive electrode active material layer, and then compression-molded by a roll press machine to produce a positive electrode. .

The positive electrode and the negative electrode obtained as described above are brought into close contact with each other through a separator made of a microporous polypropylene film having a thickness of 25 μm, and wound in a spiral shape many times to form a wound layer body. It was made.

Next, an insulating plate was inserted into the bottom of an iron-made battery can having nickel plated inside, and a wound layer body was housed. Then, in order to collect the current of the negative electrode, one end of a negative electrode lead made of nickel was pressure-bonded to the negative electrode, and the other end was welded to a battery can. Further, in order to collect current from the positive electrode, one end of a positive electrode lead made of aluminum was attached to the positive electrode, and the other end was electrically connected to the battery lid through a thin plate for current interruption. This thin plate for current interruption interrupts the current according to the internal pressure of the battery.

Then, a non-aqueous electrolytic solution was injected into the battery can. This non-aqueous electrolytic solution was prepared by dissolving LiPF ₆ as an electrolyte at a concentration of 1.0 mol / l in a mixed solvent of an equal volume of ethylene carbonate and dimethyl carbonate.

Finally, the battery lid is fixed by caulking the battery can through the insulating sealing gasket coated with asphalt, and a cylindrical non-aqueous electrolyte battery having a diameter of about 17 mm and a height of about 67 mm is obtained. It was made. The rated capacity of this battery is 1410 mAh.

Then, the obtained battery was charged, but the charging conditions were changed to evaluate the difference in charging time and capacity depending on the charging method.

<Sample 1> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.1 CmA. The charging time was the time at which 30% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.7 CmA.

<Sample 2> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.1 CmA. The charging time was the time at which 50% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.7 CmA.

<Sample 3> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.2 CmA. The charging time was the time at which 30% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.4 CmA.

<Sample 4> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.2 CmA. The charging time was the time at which 30% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.7 CmA.

<Sample 5> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.2 CmA. The charging time was the time for which 75% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.7 CmA.

<Sample 6> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.4 CmA. The charging time was the time at which 35% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.4 CmA.

<Sample 7> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.4 CmA. The charging time was the time for which 65% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.3 CmA.

<Sample 8> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.4 CmA. The charging time was the time for which 99% of the rated capacity was charged. After that, in the subsequent second charging, charging was performed at a current value corresponding to the rated capacity of 0.5 CmA.

<Sample 9> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.6 CmA. The charging time was the time at which 30% of the rated capacity was charged. Then, in the subsequent second charge, charging was performed at a current value corresponding to the rated capacity of 0.7 CmA.

<Sample 10> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.6 CmA. The charging time was the time at which 30% of the rated capacity was charged. After that, in the second charge,
Charging was performed at a current value corresponding to the rated capacity of 0.3 CmA.

<Sample 11> In this example, the sample battery was charged in two stages. First, in the first charging, charging was performed with a current value corresponding to the rated capacity of 0.6 CmA. The charging time was the time for which 80% of the rated capacity was charged. After that, in the second charge,
Charging was performed at a current value corresponding to the rated capacity of 0.3 CmA.

The charging time, the capacity, and the amount of deposited lithium of each battery charged by changing the charging conditions as described above were measured,
evaluated. The results are shown in Table 1. The charging time is
The time required to complete the charging was 300 minutes or less. In addition, the capacity was 0.2 C discharge capacity at 4.2 V charge, and a value of 1540 mAh or more was considered good. The lithium deposition amount is a value quantifying the amount of lithium deposited on the negative electrode during charging, and a value of 150 or less was considered good.

[0065]

[Table 1]

As is clear from Table 1, in the first charging, the charging time cannot be shortened in Samples 1 and 2 whose charging current value I _A is lower than 0.2 CmA. In this case, in order to shorten the charging time, the second charging current value I _B must be increased. Then, as will be described later, when the second charging current value I _B is increased, the capacity is reduced or lithium is deposited on the electrodes. In addition, sample 9-11 was higher than 0.4CmA the _{I A}
Then, the capacity has decreased. Therefore, it was found that by setting the charging current value I _A in the range of 0.2 CmA to 0.4 CmA, the charging time can be shortened without causing a capacity decrease or lithium deposition.

Regarding the charging time t _A , the charging time t
_A sample having _A of 40% or less cannot shorten the charging time. In this case, in order to shorten the charging time, it is necessary to increase the second charging current value I _B. When the second charging current value I _B is increased, the capacity is reduced or lithium is deposited on the electrodes. Further, in the samples 8 and 11 having the charging time t _A higher than 75%, the charging time cannot be shortened. Charging time t _A
It can be seen that in the sample in which is set to the time when 40% to 75% of the rated capacity is charged, the charging time can be shortened without causing capacity decrease or lithium deposition.

Next, in the second charging, the charging current value I _B
In Samples 7, 10, and 11 where is less than 0.4 CmA, the charging time cannot be shortened. Also, the samples _{I B} higher than 0.6CmA 1,2,4,5,9, lithium is accidentally deposited on the electrode. The charging current value _{I B} in a range of from 0.4CmA～0.6CmA, it was found that it is possible to shorten the charging time without causing lithium deposition.

Furthermore, in Samples 10 and 11 in which the first charging current value was increased and the second charging current value was decreased,
The charging current has dropped. It can be seen that a sufficient capacity is obtained in the sample in which the first charging current value is reduced and the second charging current value is increased.

From the above results, it is possible to prevent the deterioration of the battery characteristics by making the charging current value in the first charging lower than the charging value in the second charging and the charging current value after the second charging. It was found that the charging time can be shortened by increasing the.

Specifically, in the first charging, constant current charging is performed with a charging current value I _A in the range of the rated capacity of 0.2 CmA to 0.4 CmA, and in the second charging, the rated capacity of 0. Four
Constant current charging is performed with a charging current value I _{B in} the range of CmA to 0.6 CmA. At this time, the first charging time t _{A is set} to the time when 40% to 75% of the rated capacity is charged.

[0072]

According to the present invention, by dividing the constant current charging section that affects the charging time and selecting the optimum charging current value and charging time in each section, the charging time can be maintained without degrading the battery characteristics. Can be shortened.
That is, the present invention prevents the deterioration of the battery characteristics by lowering the charging current value in the first charging from the charging value in the second charging and increasing the charging current value after the second charging. By doing so, an excellent charging method that shortens the charging time can be realized.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing one structural example of a non-aqueous electrolyte battery charged by a charging method to which the present invention is applied.

[Fig. 2] Regarding the initial charging of a lithium-ion secondary battery,
It is a figure showing change of charging voltage and current with time.

[Explanation of symbols]

1 non-aqueous electrolyte battery, 2 positive electrode, 3 negative electrode, 4
Separator, 5 battery cans, 10 battery lid

Continued front page    F-term (reference) 5G003 AA01 BA01 CA03 CA15                 5H029 AJ02 AK02 AK03 AK05 AL02                       AL06 AL07 AL08 AL12 AL16                       AM03 AM04 AM05 AM07 BJ02                       BJ14 CJ16 HJ17 HJ18 HJ19                 5H030 AA02 AS11 AS14 BB02 BB03                       BB04 FF43

Claims (3)

[Claims] 1. A positive electrode containing a positive electrode active material capable of doping and dedoping lithium, a negative electrode containing a negative electrode active material capable of doping and dedoping lithium, and interposed between the positive electrode and the negative electrode. When charging a non-aqueous electrolyte battery provided with a non-aqueous electrolyte, a first charge in which constant current charging is performed with a charging current value I _A in a range of a rated capacity of 0.2 CmA to 0.4 CmA, and the first charging described above. After charging, the rated capacity of 0.4 CmA to 0.
And a second charge for performing constant-current charge at a charge current value I _{B in} the range of 6 CmA. 2. The first charge is 40% of the rated capacity.
The method for charging a non-aqueous electrolyte battery according to claim 1, wherein a capacity corresponding to ˜75% is charged. Wherein in the second charging, switching from constant current charging to constant voltage charging when the charging current reaches a predetermined voltage value V _1, characterized in that the constant voltage charging at the voltage value V ₁ The method for charging a non-aqueous electrolyte battery according to claim 1.