Secondary battery

Abstract

A secondary battery which can achieve battery performance satisfactorily in a low temperature environment in cold climates or the like is provided. Further, a secondary battery having high capacity even in a low temperature environment in cold climates or the like is provided. A secondary battery includes a positive electrode, a negative electrode, and an electrolyte solution which contains a nonaqueous solvent and an electrolyte. The negative electrode includes a negative electrode active material layer. The negative electrode active material layer contains graphene, a binder, and a negative electrode active material containing a particulate alloy-based material. The nonaqueous solvent contains propylene carbonate and the electrolyte contains lithium perchlorate.

Description

technical field [0001] The present invention relates to a secondary battery. Background technique [0002] In recent years, portable electronic devices such as mobile phones, smartphones, e-book readers (e-books), portable game machines, and the like have spread widely. Accordingly, research and development on secondary batteries typified by lithium secondary batteries, which are driving power sources for these devices, has been actively conducted. In addition, the importance of secondary batteries in various applications is increasing due to increasing interest in global environmental issues and petroleum resource issues, and attention has been paid to hybrid vehicles and electric vehicles. [0003] Among secondary batteries, lithium secondary batteries are widely popular because of their high energy density, and lithium secondary batteries include lithium cobalt oxide (LiCoO 2 ) or lithium iron phosphate (LiFePO 4 ) and other active materials, negative electrodes made o...

AI Technical Summary

Problems solved by technology

[0009] However, when the amount of occlusion of carrier ions increases, the volume change due to occlusion and release of carrier ions in the charge-discharge cycle is large, the adhesion between the current collector and silicon decreases, and the battery characteristics deteriorate due to charge-discharge.

Furthermore, there is a serious problem that silicon is sometimes deformed or damaged, peeled off or micronized, and as a result, the function as a secondary battery cannot be maintained.

[0013] However, when a heater circuit is installed inside the battery in order to extract the battery performance of the secondary battery in a low-temperature environment as described in Patent Document 1, the structure of the battery element and the structure of the lead-out electrodes become complicated.

In addition, the manufacturing process of the secondary battery becomes complicated

Furthermore, in order to control the heater circuit, a special control unit is required outside the secondary battery, resulting in an increase in cost.

[0014] In addition, when columnar or powdery silicon is used for the negative electrode active material layer described in Patent Document 2 to increase the capacity of the secondary battery, when charging and discharging are repeated over 10 cycles as described in this document , since the carrier ions are occluded and deintercalated by the negative active material, the volume expansion and contraction cannot be avoided

Therefore, the deterioration of the negative electrode active material layer cannot be prevented, and in Patent Document 2, the use of a layer made of black lead for current collection is sought on the premise that silicon of the active material is peeled off from the current collector.

Therefore, it is difficult to maintain the reliability of the battery with the above structure

In addition, in this structure, whether the secondary battery can perform its function in a low temperature environment is not involved

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