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Negative electrode for secondary cell,secondary cell, and method for producing negative electrode for secondary cell

A secondary battery and production method technology, which is applied to secondary batteries, battery electrodes, non-aqueous electrolyte battery electrodes, etc., can solve the problems of process yield decline, frequent chamber cleaning, etc., and achieve the effect of improving mechanical strength

Inactive Publication Date: 2008-11-05
NEC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Moreover, in the case of industrial production, a large amount of active material adheres to the inside of the chamber of the vacuum deposition equipment, causing many problems in production such as the need for frequent cleaning of the chamber
Therefore, it is conceivable that the process yield will decrease from the perspective of battery characteristics

Method used

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  • Negative electrode for secondary cell,secondary cell, and method for producing negative electrode for secondary cell
  • Negative electrode for secondary cell,secondary cell, and method for producing negative electrode for secondary cell
  • Negative electrode for secondary cell,secondary cell, and method for producing negative electrode for secondary cell

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] The present invention is described in detail with Example 1 below. The structure of the battery in this example is the same as figure 1 The same as shown, comprising a first layer 2a and a second layer 3a superimposed on a copper foil 1a providing a collector. Graphite is used as the main component of the carbon negative electrode of the first layer 2a. The second layer is mainly composed of Si powder dispersed in a binder, and is formed by a coating method. Next, the production method of the battery will be described.

[0055]First, as shown in FIG. 3, a first layer 2a made of graphite with a thickness of about 50 μm is deposited on a copper foil 20 with a length of about 2000 m and a thickness of 10 μm, which serves as a negative electrode collector which is an elastic support. The first layer 2a made of graphite is formed by mixing graphite powder, polyvinylidene fluoride dissolved in N-methyl-2-pyrrolidone as a binder, and a conductive additive to form Paste, t...

Embodiment 2

[0067] The negative electrode was produced in the same manner as in Example 1, except that the active material contained in the second layer 3a was Li:Si alloy, and then the performance of the battery was evaluated. The experimental results are shown in Table 1. The initial charge / discharge efficiency in Example 2 was 92.4%, while that in Comparative Example 2 was 84.4%. It can be understood from the experimental results that the initial charge / discharge efficiency in Example 2 is high compared with Comparative Example 2 in which the second layer 3a (Li:Si alloy) is formed by vacuum deposition.

[0068] Assuming that the discharge capacity for one cycle is 100% when expressed as a percentage, the ratio of the discharge capacity for 500 cycles (C500 / C1 discharge capacity ratio) is greater than 80%, that is, even after the 500th cycle, the discharge capacity remains the same. It can maintain more than 80% of the initial capacity, which is much better than Comparative Example 2 ...

Embodiment 3

[0072] Produce negative pole with the same method as embodiment 1, only the active material that the second layer 3a contains is SiO X , and then evaluate the performance of the battery. The experimental results are shown in Table 1.

[0073] The initial charge / discharge efficiency in Example 3 was 89.1%, while that in Comparative Example 3 was 74.3%. It can be understood from the experimental results that the second layer 3a (SiO X ) is formed by vacuum deposition method Compared with Comparative Example 3, the initial charge / discharge efficiency in Example 3 is high.

[0074] Assuming that the discharge capacity for one cycle is expressed as a percentage, it is 100%, and the ratio of the discharge capacity for 500 cycles (C500 / C1 discharge capacity ratio) is greater than 80%, that is, even after the 500th cycle, the discharge capacity It can still maintain more than 80% of the initial capacity, which is much better than Comparative Example 3 (it is damaged after 200 cycle...

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Abstract

A multilayer negative electrode having a carbon layer as a first layer, realizing high battery capacity in the range of voltages at which a battery is actually used while maintaining high charge / discharge efficiency and good cycle characteristics by a simple method. A first layer (2a) the major component of which is carbon and a second layer (3a) the major component of which is filmy material having lithium ion conductivity are stacked on copper foil (1a). The second layer (3a) is formed by dispersing at least one kind of metal particles, alloy particles, and metal oxide particles in a solution in which a binder is dissolved and applying and drying the coating solution.

Description

technical field [0001] The invention relates to a negative pole for a secondary battery, a secondary battery and a production method for the negative pole for a secondary battery. Background technique [0002] With the widespread use of mobile terminal machines such as portable phones and notebook type personal computers, the role of secondary batteries used as power sources for such mobile terminal machines has been gaining importance. These secondary batteries for terminal equipment are required to be miniaturized / lightweight, and have a high capacity and have characteristics that are not easily deteriorated when they are discharged and recharged many times. [0003] Examples of secondary batteries include lithium-ion secondary batteries, whose negative electrodes actually use carbon materials such as graphite and hard carbon that can absorb and emit lithium ions in view of high energy density, excellent charge-discharge cycle characteristics, and high safety . However, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/02H01M4/04H01M4/38H01M10/05H01M4/13H01M4/133H01M4/134H01M4/139H01M4/1393H01M4/1395H01M4/36H01M4/40H01M10/052H01M10/0525H01M10/0566
CPCY02E60/12H01M10/0587H01M4/525H01M10/0525H01M4/1393H01M4/134H01M4/405H01M4/133H01M4/505H01M4/1391H01M4/1395H01M4/366H01M4/485H01M4/38H01M4/139Y02E60/122H01M4/131H01M4/386H01M4/387Y02E60/10H01M4/13
Inventor 宇津木功二山本博规入山次郎森满博三浦环坂内裕宫地麻里子山崎伊纪子
Owner NEC CORP
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