Battery, method of charging and discharging the battery and charge-discharge control device for the battery

a technology of battery and control device, which is applied in the direction of secondary cell servicing/maintenance, non-aqueous electrolyte cells, cell components, etc., can solve the problems of increasing the capacity of the battery, accelerating the electrolyte solution, and reducing the collection property of current, so as to reduce the structural fracture of the anode and improve the cycle characteristics

Inactive Publication Date: 2005-09-29
SONY CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0007] In view of the foregoing, it is an object of the invention to provide a battery capable of improving cycle characteristics through reducing a structural fracture of an an

Problems solved by technology

However, in a currently typical lithium secondary battery which uses lithium cobalt oxide for a cathode and graphite for an anode, its battery capacity has reached the saturation point, so it is extremely difficult to significantly increase its capacity.
However, when charge and discharge are repeated, the anode with a high capacity is broken into small pieces due to severe expansion and shrinkage of an active material, thereby a current collecting property declines, and the decomposition of an

Method used

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  • Battery, method of charging and discharging the battery and charge-discharge control device for the battery
  • Battery, method of charging and discharging the battery and charge-discharge control device for the battery
  • Battery, method of charging and discharging the battery and charge-discharge control device for the battery

Examples

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examples

[0077] Examples of the invention will be described in detail below referring to the drawings. In the following examples, like components are donated by like numerals as of the above embodiment.

examples 1-1 through 1-6

[0078] Coin-type secondary batteries with a diameter of 20 mm and a thickness of 16 mm shown in FIG. 1 were formed. The cathode 12 was formed through the following steps. At first, lithium carbonate (LiCO3) and cobalt carbonate (CoCO3) were mixed at a molar ratio of LiCO3:CoCO3=0.5:1 to form a mixture, and the mixture was fired for 5 hours at 900° C. in air to obtain lithium cobalt oxide (LiCoO2) as a cathode active material. Next, the lithium cobalt oxide, graphite as an electrical conductor and polyvinylidene fluoride as a binder were mixed at a mass ratio of lithium cobalt oxide:graphite:polyvinylidene fluoride=91:6:3 to form a mixture. Next, the mixture was dispersed in N-methyl-2-pyrrolidone as a dispersion medium to form mixture slurry, and the mixture slurry was applied to the cathode current collector 12A made of aluminum foil with a thickness of 20 μm, and dried, the mixture slurry was pressurized to form the cathode active material layer 12B, and then the cathode current c...

examples 2-1 through 2-3

[0088] Secondary batteries were formed as in the case of Example 1-5 or Example 1-6, except that the composition of the electrolyte solution was changed. As the electrolyte solution, an electrolyte solution formed through adding 1,3-dioxol-2-one (VC) or 4-vinyl-1,3-dioxolane-2-one (VEC) to the electrolyte solution used in Examples 1-1 through 1-6, that is, the electrolyte solution including the solvent which included ethylene carbonate and dimethyl carbonate at a mass ratio of 1:1 and LiPF6 which was dissolved in the solvent at a concentration of 1 mol / l was used. At that time, the contents of VC and VEC in the electrolyte solution were changed as shown in Tables 2 and 3 in Examples 2-1 through 2-3.

[0089] A charge-discharge test was carried out on the secondary batteries of Examples 2-1 through 2-3 as in the case of Examples 1-5 and 1-6 to determine their capacity retention ratios in the 100th cycle and measure the Li / Si ratio in the anode 14 and the potential of the anode 14 vs. L...

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Abstract

Provided is a battery capable of improving cycle characteristics through reducing a structural fracture according to charge and discharge of an anode and a reaction of the with an electrolyte. An anode active material layer includes at least one kind selected from the group consisting of a simple substance and alloys of Si capable of forming an alloy with Li. A cathode and an anode are formed so that the molar ratio Li/Si in the anode at the time of charge is 4.0 or the potential of the anode vs. Li is 0.04 V or more through adjusting, for example, a ratio between a cathode active material and an anode active material. Moreover, the cathode and the anode are formed so that the molar ratio Li/Si in the anode at the time of discharge is 0.4 or more, or the potential of the anode vs. Li is 1.4 V or less.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a battery comprising an anode which includes silicon (Si) as an element and is capable of inserting and extracting lithium (Li), a method of charging and discharging the battery, and a charge-discharge control device for the battery. [0003] 2. Description of the Related Art [0004] In recent years, as mobile devices have become more sophisticated and multifunctional, a demand for higher capacity of secondary batteries as power sources for the mobile devices has been made. As a secondary battery which meets the demand, a lithium secondary battery is cited. However, in a currently typical lithium secondary battery which uses lithium cobalt oxide for a cathode and graphite for an anode, its battery capacity has reached the saturation point, so it is extremely difficult to significantly increase its capacity. Therefore, using lithium metal for an anode has been considered since a long tim...

Claims

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Application Information

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IPC IPC(8): H01M4/134H01M4/1395H01M4/36H01M4/38H01M4/64H01M4/66H01M10/05H01M10/052H01M10/0567H01M10/0569H01M10/42H01M10/44
CPCH01M4/0404H01M4/0471H01M4/134H01M4/1395H01M4/38Y02E60/122H01M10/052H01M10/0569H01M10/44H01M2004/021H01M2010/4292H01M4/661H01M4/386Y02E60/10H01M4/02H01M4/64H01M10/05
Inventor KUBOTA, TADAHIKO
Owner SONY CORP
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