**1. Introduction**

In Ecuador, the presence of hybrid vehicles in recent years has had a growth in sales. These vehicles have a traction system based on an electric motor coupled to a combustion engine and a high voltage battery as an energy source. The presence of more than 20,000 vehicles sold from 2009 to 2020 (**Figure 1**) [1], raises concern especially about the high-voltage battery, which in some cases has already reached its useful life. In the country there are no recycling procedures and regulations for the treatment of the different chemical compounds of this type of batteries, this may generate a large environmental impact in the future.

These batteries are generally made of Nickel Hydride metal (NiHm), according to studies presented in [2–4] indicate that their reuse is possible to store energy in a SLB process. Its application in second-life energy storage systems would help in our country to generate NiHm battery reuse projects that in the future would reduce the environmental impact and pollution that these batteries could cause.

**Figure 2.**

*Types of NiHm batteries in HEV presents in Ecuador. a) Prius C battery, b) Toyota Highlander battery.*

The high-voltage batteries for hybrid vehicles with the most presence in Ecuador are of the NiHm type (**Figure 2**). The battery set is made up of several modules connected in series, these modules are of type NP2 and NP2.5. In addition, it has a control system based on high voltage relays, a cooling system that is activated based on the temperature sensors and a battery management module that is responsible for the supervision of each of the modules.

The NiHm batteries are robust systems that has higher capacity and low maintenance compared to nickel cadmium battery (NiCd). Several laboratories have developed feasibility studies on the use of NiHm batteries in their second life. The studies focus on analyzing the behavior of reused batteries vs new batteries of different chemical compounds, the results show that the use of these batteries in stationary systems is possible with good results [5]. If we consider that SBL systems with lithium-ion batteries are currently being implemented in different countries and show high efficiency and are less expensive, it is due to a high presence of Electric vehicles in these countries [6–15]. But if we compare them with our country, the greatest presence of batteries in the recycling process is that of hybrid vehicles based on NiHm, which allows us to generate an alternative for reuse in energy storage systems.

#### *The Second Life of Hybrid Electric Vehicles Batteries Methodology of Implementation in Ecuador DOI: http://dx.doi.org/10.5772/intechopen.99058*

In continental Ecuador, the battery energy storage system is limited, there are no projects that are developed in this line. In the Galapagos Islands there are projects that consider energy storage based on lead-acid batteries and lithium ion batteries. These projects represent a little less than 5% of all generation capacity on the islands [16]. For all this and the presence of hybrid vehicles, it is proposed to use NiHm batteries as energy storage as an additional supply and with this contribute to caring for the environment and reduce the use of fossil fuels for electricity generation.

This chapter contributes to the search for new sources of energy power based on the use of batteries present in hybrid vehicles and that due to their operating condition can be adapted to a second life process, in the same way it is provided with a methodology for its implementation. Through its implementation, it seeks to improve the recycling processes of this type of batteries and contribute to the care of the environment.The structure of this chapter is as follows: in Section 2 a description of methodology proposed for the implementation of SLB based in NiHm battery of HEV is presented. The Section 3 presents two possible scenarios for the implementation of SBL with NiHm batteries where a comprehensive analysis is presented on the energy demand of each scenario and how much energy storage system with NiHm batteries can contribute if it were to be implemented in each case, considering the proposed methodology; while the conclusion is presented in Section 4.
