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Positive electrode for lithium-ion secondary cell, and lithium-ion secondary cell

A secondary battery, lithium ion technology, used in secondary batteries, battery electrodes, electrode carriers/current collectors, etc., can solve the problems of low internal resistance, unclear density of active material layers, and difficulty in making high capacity, and achieve internal The effect of low resistance, fast charge and discharge output power, and high output power

Inactive Publication Date: 2017-05-17
MITSUBISHI MATERIALS CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0020] The positive electrode for a lithium ion secondary battery described in Patent Document 6 has an active material layer with a thickness of about 140 μm, which is thicker than a conventional active material layer with a thickness of about 100 μm. Increase the capacity of lithium-ion secondary batteries using this positive electrode
[0021] Thus, it has been difficult to manufacture lithium-ion secondary batteries with high capacity and low internal resistance

Method used

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  • Positive electrode for lithium-ion secondary cell, and lithium-ion secondary cell
  • Positive electrode for lithium-ion secondary cell, and lithium-ion secondary cell
  • Positive electrode for lithium-ion secondary cell, and lithium-ion secondary cell

Examples

Experimental program
Comparison scheme
Effect test

Embodiment I

[0145] (1) Fabrication of electrochemical cells

Embodiment 1

[0146] In Examples 1-6, the positive electrode for lithium ion secondary batteries of this invention using LCO as an active material was produced, and it was applied to the positive electrode of an electrochemical cell. The electrochemical cells of Examples 1 to 6 differ in the depth of the pores formed in the active material layer, but have the same other structures. Therefore, the fabrication method of the electrochemical cells will be described using Example 1 as an example.

[0147] First, LCO as an active material, PVDF as a binder, and AB as a conductive additive were measured in a mass ratio of 95:3:2. Thereafter, the measured amount of PVDF was added to N-methyl-2-pyrrolidone (NMP) as a solvent, and stirred for 20 minutes. Furthermore, LCO and AB were added and stirred to obtain a positive electrode slurry whose viscosity was adjusted to 5 Pa·s.

[0148] Next, prepare an aluminum foil with a thickness of 15 μm cut into a size of 3 cm × 3 cm as a collector, and apply t...

Embodiment 5

[0209] The electrochemical cell of Example 5 has a hole penetrating through the active material layer and forming a bottom with aluminum foil. On the other hand, the electrochemical cell of Example 6 has a through hole penetrating the aluminum foil and the active material layer. In this way, when comparing Example 5 and Example 6, there is a difference between Example 5 and Example 6 whether or not through-holes are formed in the aluminum foil. However, the discharge capacity values ​​of the electrochemical cells of Example 5 and Example 6 were equal. In this way, even if through-holes are formed in the aluminum foil, the performance of the battery will not be degraded.

[0210] (3-2) Relationship between the center spacing of the pores of the active material layer and the characteristics of the electrochemical cell

[0211] As shown in Table 2, the embodiment The electrochemical cell, the center interval of the hole is Pores were formed at the positive electrode at inte...

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Abstract

This positive electrode (2) for a lithium-ion secondary cell is provided with a collector (5) and an active material layer (6) formed on the surface of the collector (5). The active material layer (6) has a plurality of holes (7) formed on the surface thereof, has an active material density that is 68-83% of the true density of the active material contained in the active material layer (6), and has a thickness of 150-1,000 [mu]m, and therefore has more of the active material. When used in a lithium-ion secondary cell, the positive electrode (2) provides a lithium-ion secondary cell in which electrons are transferred and lithium ions are inserted and desorbed not only on the surface of the active material layer (6) but also at positions located deep from the surface of the active material layer (6) in the thickness direction; the active material located deep from the surface of the active material layer (6) in the thickness direction can be effectively utilized; and charging / discharging can be performed more rapidly at a higher capacity.

Description

technical field [0001] The invention relates to a positive electrode for a lithium ion secondary battery and the lithium ion secondary battery. Background technique [0002] Lithium-ion secondary batteries have attracted attention as high-capacity secondary batteries, and various developments for improving the performance of lithium-ion secondary batteries are underway (see Patent Documents 1 to 6, etc.). [0003] Patent Document 1 discloses the following electrodes. This electrode includes: a current collecting layer having conductivity and formed in a thin film; an active material layer having concavities and convexities formed on a side opposite to the current collecting layer; and an adhesive layer bonding the current collecting layer and the active material layer. In the electrode disclosed in Patent Document 1, the distance from the surface of the active material layer to the collector layer is reduced in the concave portion of the active material layer, and the inter...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/136H01M4/36H01M4/505H01M4/525H01M4/58H01M4/74H01M10/0525H01M10/0585H01M4/131
CPCH01M4/136H01M4/505H01M4/525H01M10/0525H01M4/131H01M4/485H01M4/5825H01M2004/021Y02E60/10Y02P70/50H01M4/13H01M4/364H01M4/80H01M4/74H01M4/623H01M4/625H01M2004/028
Inventor 秋草顺清水翔柳繁成
Owner MITSUBISHI MATERIALS CORP
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