Functional Components of an Electrochemical Energy Storage Device

The functional components of electrochemical energy storage devices have been depicted in Figure 7.1. The electrodes are chosen depending on the potential difference criteria.

The purpose of a negative electrode is to give electrons to the load during discharge, whereas the purpose of a positive electrode is to accept the electrons from the source during recharge.

The electrolytes are meant for ionic transport during recharge and discharge to maintain the electrodynamic equilibrium. Moreover, an electrolyte should be able to withstand the potential difference without dissociation. The details regarding the different functionalities with Figure 7.1 as the focal point have been tabulated in Table 7.2.

Correlation with Power Grid

Generally, a storage system reserves energy by accumulating economically available electrical energy and provides electricity when necessary, attracting premium in terms of monetary aspects or for essential services. Energy storage is a malleable resource for a power grid that can be relied upon for delivering a range of services.

Charge storage model of a non-faradaic energy storage cell

FIGURE 7.1 Charge storage model of a non-faradaic energy storage cell.

TABLE 7.2

Understanding the Essential Functional Components of an Energy Storage Cell

Component's

Name

Illustration of the Components

Supplementary Description

Negative

electrode

Graphene nanostructures, silicon forests

Graphene layers with intercalated lithium ions [7]. Reproduced with permission of the International Union of Crystallography, (http://journals.iucr.org/)

Positive

electrode

Intercalation structures such as olivine electrodes, spinel electrodes, etc.

Low cost, low toxicity lithium ferrous olivine phosphate structure with lithium ions shown as big spheres [7]. Reproduced with permission of the International Union of Crystallography, (http://journals.iucr.org/)

Electrolyte

solvents

Solvents have a common feature of slightly negatively charged oxygen atoms due to the double bonding, which causes polarization-induced dissolution

Examples of electrolyte solvents: ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. Solvents do not participate in the cell electrochemistry However, the wettability of the electrolyte with the electrode plays a very crucial role in enhancing the efficacy of the electrodes for enhancing the mass transfer mobility in the electrolyte

This is achieved by building proper interfacial contacts for the electrodes and choosing appropriate electrolytes [S]

TABLE 7.2 (Continued)

Understanding the Essential Functional Components of an Energy Storage Cell

Component's

Name

Illustration of the Components

Supplementary Description

Electrolyte

salts

The electrolyte is generally known by its salt name

Which could be either of the following - hexafluorophosphate, tetrafhioroborate, perchlorate etc.

Separators

Separation is achieved by dint of nanoscopic structures

It is a permeable nano-membrane with cavities large enough to allow ions to pass through unbridled, but small enough that the bipolar electrode particles are electronically insulated

Current

collector

Typically like the aluminum foil used in food packaging, but much reduced thickness

The high potential region uses aluminum foil; whereas the low potential region uses copper foil

Energy Asset Arbitrage

Energy is an invaluable asset, as the strength of the economy of a nation depends upon its energy security and self-dependence. However, the pricing of energy varies a lot across the different contours of its harvesting. Electrical energy being the entropically most favored form of energy facilitates energy exchange across different modes of energy. The different types of energies harnessed from different avenues differ in their prices depending on various factors related to their demand and supply. A conventional power grid has little provision for amply rewarding electrical energy subscribers who might be generating excess energy by renewable energy harvesting. Energy storage devices allow' the proprietor or person interested in energy harvesting to gain maximum benefits from energy, by allowing them to store and wait till they get satisfactory premium for their energy harnessing efforts. This is done by utilizing arbitrage concepts from the finance sector, w'hich help a business entity to make profits by capitalizing on the difference in price of a commodity across different sectors.

Demand Side Management

The load consumption pattern at consumer premises varies depending on the requirements of the utilization of the connected capacity. The grid authorities have laid clear-cut guidelines for power consumption pertaining to time-segmentation of the day. During peak hours of load consumption, the current drawn from the grid is very high. Hence it is advisable that non-vital power consumption may be avoided during peak hours. During off-peak hours, when the vital industrial activities are dormant, the essential domestic load utilization may be carried out, and such a practice is very much encouraged and incentivised. However, such practices of demand side management can be efficiently implemented only when the supply and utilization are decoupled through energy storage devices.

Assurance of Reliability

It balances rapid transients in demand and supply, particularly where high-inertia alternators (e.g., steam turbines) have become obsolescent. The temporal decoupling of energy supply and utilization allows us to maintain the electricity utilization if the electricity supply is disrupted by contingencies. The success of distributed energy resources in delivering the promise of reliability depends on energy storage devices.

Infrastructure's Utility Optimization and Infrastructure's Deployment Deferment

Millennial entrepreneurs strongly believe that successful business start-ups operate on the asset-lite model. This means that entrepreneurial endeavors in the field of power sector must be done with minimal infrastructure requirements, focusing more on creating a problem-solving product and platform. Energy storage devices and systems are pivotal in the optimum utilization of the existing infrastructure and delaying the need for infrastructure deployment unless it is absolutely essential. This is true even in the utilization at consumer premises, apart from being witnessed in the generation, transmission, and distribution.

Predictability Enhancement of Non-conventional Resources

The renewable resources of energy which steer the incorporation of distributed generation in the existing power grids have given considerable advantages except for being dependent on geographical conditions. The deployment of energy storage systems has facilitated the accumulation of abundance of energy from renewable sources for reserving and dispatching it when there is a deficit of insolation or windage power.

 
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