Environmental and Economic Benefits Induced by a Remanufactured Portable Power Station

Abstract

The recent announcement by the European Union of the Fit for 55 Package and a prospective ban on the sale of new internal combustion engine vehicles by 2035 has prompted a notable surge in the electric vehicle (EV) market. The shift toward EVs concurrently presents challenges, namely the resource management of used EV batteries, particularly their reuse, recycling, and remanufacturing. Accordingly, this study aims to analyze the effects of the reduced environmental impacts of a remanufactured portable power station (RPPS) compared with those of a new portable power station (NPPS) using life cycle assessment (LCA) and the economic benefits gained from reusing used EV batteries. The results of the LCA of the RPPS indicated a notable environmental advantage, with reductions of 42.01% in GWP and 41.91% in ADP compared with those achieved by the NPPS. Moreover, the economic benefits of the waste battery remanufacturing business amounted to USD 593,212 at an annual sales volume of 1000 units. The environmental benefits of remanufacturing practices represent valuable support for policies centered on remanufacturing and reusing used EV batteries. The findings of this study could stimulate a future market for products repurposed from used EV batteries, thereby further fostering sustainability in this sector.

1. Introduction

The European Union announced Fit for 55 at the European Green Deal on 14 July 2021, confirming a ban on the sale of new vehicles with internal combustion engines in 27 member countries from 2035 [1]. The policy shift is expected to stimulate growth in the market for electric vehicles (EVs). Furthermore, industries associated with the circular economy in EV batteries and resource management, encompassing processes such as the recycling, remanufacturing, and repurposing of used EV batteries, have gained prominence. Waste EV batteries could be repurposed strategically for energy storage systems (ESSs) provided the residual capacity remains above 80% of their original capacity. Moreover, beyond their use for ESSs, retired EV batteries could be applied in electric charging stations, products with low energy output, emergency generators, and portable power stations (PPSs), in addition to their role in energy storage [2,3]. However, substantial capacity decline and severe damage necessitate the extraction and recycling of valuable metals in these batteries [4,5]. Choosing a strategic approach, it makes sense to prioritize reusing batteries over immediate recycling unless significant damage is apparent. Commencing with reuse before recycling not only extends the battery lifespan but also has the potential to reduce the necessity for new battery production, consequently reducing environmental impact [6].

In this regard, Lee [7], Kim [8,9], Jung [10], and Jasper [11] focused on life cycle assessment (LCA) for fuel cell-based energy storage systems. Philippot et al. [6] analyzed two distinct scenarios, with the first involving repurposing discarded EV batteries for continued use within EVs, and the second exploring their reuse as stationary ESSs after repurposing. Similarly, Loakimidis et al. [12] compared the environmental implications of reutilizing used EV batteries as components of EVs with those of repurposing them for employment in ESSs. Ahmadi et al. [13] conducted an LCA employing a lithium-ion battery pack in an EV as a stationary ESS. Wang et al. [14] performed an LCA of lithium iron phosphate batteries from the manufacturing phase, use, potential for reuse, and eventual recycling. This study set up two end-of-use/life (EOL) scenarios, namely one in which the battery is recycled after being reused as an ESS, and the other in which the battery is recycled immediately after being reused in an EV. In addition, an energy supply scenario was added to compare and analyze the environmental effects of using the Spanish electricity mix and energy supply from solar photovoltaic (PV) panels. Cusenza et al. [15] and Bobba et al. [16] conducted LCAs with EV lithium-ion batteries reused as ESSs in a solar power plant power grid. Yu [17] conducted an LCA of four types of lithium-ion batteries for EVs and evaluated the environmental and economic effects of three recycling methods.

Table 1. Studies with life cycle assessment (LCA) on battery systems.

Study	LCA Target	System Boundary	LCI Data	Use of Primary Data
Philippot et al. [6]	Repurposed traction batteries after their use in EVs	Manufacturing, first use stage, repurposing, and reuse	Ecoinvent database	EV battery cells
Lee et al. [7]	A solid oxide fuel cell (SOFC)-based power generation system	Manufacturing, operation, and disposal	Ecoinvent database	Not considered
Kim et al. [9]	Molten carbonate fuel cell (MCFC) system and polymer electrolyte membrane fuel cell (PEMFC) system	Fuel production, manufacturing, and operation	Korean national LCI DB, Ecoinvent database	Fuel cell system
Kim et al. [10]	MCFC system	Pre-manufacturing, manufacturing, installation, and operation	Korean national LCI DB, Ecoinvent database	Not considered
Jasper et al. [11]	A photovoltaic (PV) home battery storage system	Primary material extraction, production, use phase, and recycling	Ecoinvent database	Battery system periphery
Loakimidis et al. [12]	A lithium iron phosphate (LFP) battery	Manufacturing, use, and disposal	Ecoinvent database	Not considered
Ahmadi et al. [13]	A Li-ion battery pack	Li-ion battery manufacturing, first use in the EV, re-purposing, second use in the ESS, and recycling	Ecoinvent database	Not considered
Wang et al. [14]	LFP batteries	Battery manufacturing, use, battery reuse and recycling	GaBi databases	Battery manufacturing
Cusenza et al. [15]	A BESS made by retired Li-ion EV batteries, a photovoltaic plant (20 kW), and the electricity grid	Operation	Ecoinvent database	Not considered
Bobba et al. [16]	Repurposed batteries	Manufacturing, repurposing, use, and end-of-life	Ecoinvent database	Not considered

provides an overview of the literature review results.

In their studies, Ahmadi et al. [13] and Wang et al. [14] adopted the ReCiPe (ReCiPe is a method for the life cycle impact assessment (LCIA). The method has been given the name ReCiPe as it provides a ‘recipe’ to calculate life cycle impact category indicators. The acronym also represents the initials of the institutes that were the main contributors to this project and the major collaborators in its design: RIVM and Radboud University, CML, and P RRé Consultants) methodology, including diverse parameters such as global warming potential (GWP), abiotic depletion potential (ADP), particulate matter formation potential (PMFP), freshwater eutrophication potential (FEP), photochemical oxidant formation potential (POFP), and fossil depletion potential (FDP). In their research, Cusenza et al. [15] used 14 impact categories. In other studies, Phillippot et al. analyzed the impact on GWP and acidification [5], whereas Bobba et al. [16] analyzed the impact on GWP and ADP, with the LCA results related mainly to those of the impact categories. As outlined previously, a considerable body of research has been dedicated to the LCA of lithium batteries in EVs. Ample research has been conducted to investigate the environmental ramifications of repurposing batteries as stationary ESSs after their use in EVs. To the best of our knowledge, to date, no empirical study has comparatively analyzed the environmental characteristics of products incorporating reusable batteries and products using new batteries. Moreover, given the difficulty in obtaining primary data in most studies, it appears that data were acquired through the literature, excluding the four studies in Table 1.

According to Kang [18], remanufacturing could significantly reduce costs. However, studies pertaining to the economic evaluation of repurposing and recycling used EV batteries have focused primarily on the recycling phase, with a notable omission of the entire product lifecycle.

Table 2. Studies with economic evaluation of EV battery reuse/recycling.

Study	Contents
Kampker et al. [19]	Cos and benefit analysis of three chosen scenarios: reuse, repurpose, and recycle
Omrani et al. [20]	An economic evaluation of reusage of lithium-ion packs for load leveling in the residential, industrial, and photovoltaic power plant sectors
Bai et al. [21]	An economic performance evaluation by net present value of distributed solar photovoltaics (DSPV) with reused batteries as energy storage systems (RBESS)
Rallo et al. [22]	Investigates the current state of the art of disassembling activities by analyzing the Li-ion battery and provides insights into the costs of each disassembling operation, from battery level to cell level
Han et al. [23]	An economic estimation for a PV charging station based on the utilization of retired electric vehicle batteries

provides an overview of the literature review results regarding the economic evaluation of EV battery reuse/recycling. Most literature studies primarily focus on the economic evaluation of EV battery reuse, recycling, and repurposing processes. However, there seems to be a lack of economic assessments that consider both the revenue and costs associated with the sale of specific systems and products using waste EV batteries.

The literature review on LCA studies of battery systems revealed a research gap, indicating a lack of primary data for products and systems, with limitations to certain battery systems. Also, the scientific relevance we considered when choosing the product is how remanufactured products contribute to improving the environment. Remanufacturing is the activity of using used products or parts to create items with the same performance as new ones through a series of specialized processes [18]. Hence, we compared the environmental impact of remanufactured items (RPPSs) and regular ones (NPPSs) with similar performances to assess their environmental impacts. Additionally, in the case of economic evaluation, existing research has primarily focused on the economic assessment of recycling methods for EV batteries, with a lack of economic analysis for products sold using waste EV batteries.

The primary objective of the current study is to address the significant research gaps observed in existing studies. We conducted an LCA, using two PPS products as examples. The first product, RPPS, utilizes used batteries from EVs for remanufacturing, while the second product, NPPS, uses new LFP batteries. The goals of the current study are as follows: (1) to quantify the environmental impact of the RPPS and NPPS among similar models; (2) to identify the hotspots and the stages with the most significant environmental impact throughout the life cycle; (3) to derive the economic benefits by calculating the costs and revenues associated with selling RPPSs. This study can provide environmental and economic advantages of the remanufacturing of used EV batteries, thereby promoting the growth of the battery remanufacturing market and contributing to the establishment of a circular economy system.

2. Remanufacturing Process of a Portable Power Station

The remanufacturing procedure of a PPS is shown in Figure 1. The process is initiated by a meticulous visual examination of the battery pack. This step entails a thorough assessment of any visible damage to the battery pack to determine whether a specific unit warrants further inspection. Subsequently, if the external condition of the battery is satisfactory, the battery pack is disassembled into pack, module, and cell units. Subsequently, a comprehensive performance test/evaluation is performed on the dismantled battery cells, covering tests on insulation resistance, capacity, and internal resistance. The cell units are assessed, and the test results are utilized to categorize cells with similar performance characteristics. Afterward, cells with similar test results are classified and reassembled using a battery pack for the PPS. These PPS products are produced by assembling parts, such as reassembled battery packs, external cases, control boards, and displays. After assembling the components, a quality inspection is performed, including an evaluation of their appearance, functionality, and safety. Finally, the complete product is packaged into individual units, placed in a designated storage bag, and enclosed in a box for shipping.

3. Environmental Impact Analysis Methods

The environmental effects of the RPPS and NPPS were evaluated using LCA, which is an internationally standardized environmental assessment methodology specified in the 14040 series of the International Organization for Standardization [24]. The LCA is used to analyze the environmental load and potential environmental impact occurring ‘from cradle to grave’ of a product. The four key phases of an LCA study are described in Figure 2. Initially, the goals and scope are defined, outlining the study’s objectives and boundaries. The second phase, the Inventory Analysis (LCI), entails collecting comprehensive data on material and energy flows. Subsequently, the Impact Assessment (LCIA) phase provides additional insights into the environmental significance of identified impacts. Finally, the Interpretation phase summarizes results, facilitating conclusions and decisions aligned with the study’s goals and scope [24].

The methodology is well suited for presenting the dual objectives of resource conservation and environmental impact reduction, which are central to the concept of repurposing [25]. We used the following procedure in our study. First, the products, functions, and functional units subjected to the LCA were defined. Second, the scope of the study was determined by setting target system boundaries. Third, the data at each stage were collected and processed based on functional units. Fourth, the environmental impact was evaluated based on the collected and analyzed data. Finally, the environmental benefits of remanufacturing were derived by comparing and analyzing the LCA results of the RPPS and NPPS.

3.1. Data Collection and Calculation

The data quality used for the environmental assessment of the product is as described in

Table 3. The data quality used for LCA of RPPS and NPPS.

		RPPS	NPPS
Premanufacturing	Bill of material (kg)	On-site data from RPPS manufacturer	Assumptions based on the RPPS on-site data and NPPS references
Manufacturing	Electricity use (kWh)	On-site data from RPPS manufacturer	Assumptions based on the RPPS on-site data
Distribution	Transport (km)	Average data from RPPS manufacturer	Assumptions based on the RPPS on-site data
Use	Electricity use (kWh)	Assumptions based on the statistical data	Assumptions based on the statistical data
End-of-use/life	Waste disposal rates	Statistical data	Statistical data

. For the data collection in the premanufacturing, manufacturing, and distribution stages of the RPPS, on-site data were acquired directly from Company G (Yangju-si, Republic of Korea), the manufacturer of the RPPS. In the case of other stages and the NPPS, assumptions, statistical data, and LCI DB were mainly used. In summary, for the premanufacturing, manufacturing, and distribution stages of the RPPS, primary data were utilized, while for all other stages of the RPPS and all stages of the NPPS, secondary data were used. The LCI DB used in this study involves the Korean national LCI DBs and Ecoinvent 3.8.

3.1.1. Premanufacturing

The premanufacturing phase comprises the extraction of primary resources, processing of these resources into raw materials, and subsequent fabrication of components. As regards the input of component information into the RPPS, data pertaining to the material and weight of each component were compiled from Company G. As acquiring NPPS component information through direct manufacturing channels is not feasible, data could alternatively be gathered from product sales websites. The lithium iron phosphate batteries used in the NPPS were produced and assembled in China, along with other parts, which were transported to the Republic of Korea, packaged, and sold. It was assumed that the components used in the NPPS had the same composition as each component of the RPPS, and the weight was calculated by reflecting the total weight of the NPPS and the weight ratio of the parts of the RPPS.

3.1.2. Manufacturing

In the manufacturing stage, each component was assembled and its performance was evaluated. The electricity consumption data directly consumed by the manufacturing facilities were collected in this step. The electricity consumption required to produce one product was allocated based on the number of products produced during the period after collecting the annual consumption data. The data from Company G were collected for the electricity consumption of the RPPS; however, owing to data security issues, it was difficult to collect data and it was assumed that the electricity consumption of the NPPS was the same as for the RPPS based on functional units.

3.1.3. Distribution

A transportation scenario from the manufacturing plant distributed to each consumer was considered. The annual product sales ratio by region was collected from Company G data, and the transport distance by region was obtained from Annex 3 of the Korean Product Category Rules (PCR) [26]. For the NPPS, transportation from China to the Republic of Korea and from Korean product distributors to consumers was considered.

3.1.4. Use

During the use stage, when the PPS was charged, data on the power consumed by the charger that was not used for charging were collected. The environmental impact of electricity consumption was calculated by referring to the power consumption derived from the charging calculation method of portable wireless communication devices for the internet (EPD 024) in the Republic of Korea [27]. The total electricity consumption of charging a PPS was calculated using Equation (1). For the annual number of charges in Equation (1), statistical data on the average number of camping events and the number of car camping events per year were used [28].

$${TE}_C=P\times A\times Dt\times {10}^{-3}$$

(1)

${TE}_C$: total electricity consumption (kWh);

$P$: power consumption per charge (kWh/event);

$A$: number of recharges per year (events/year);

$Dt$: lifespan of portable wireless communication devices for the internet (years).

3.1.5. End-of-Use/Life

For the end-of-use/life scenario, the recycling, landfill, and incineration ratios were set by referring to the Product Environmental Footprint Category Rule (PEFCR) battery.

Table 4. Battery PEFCR scope [29].

Battery Types Included for This PEFCR
1	E-mobility (e.g., e-bikes, end-of-life vehicles (ELVs), plug-in hybrid electric vehicles (PHEVs), cars, bus/trucks), excluding charging units
2	Information and Communication Technologies (e.g., tablets and phones, computers, cameras, games), including charging units
3	Cordless power tools (e.g., drills, electric screwdrivers), including charging units
4	Battery technology: Li-ion and nickel–metal hydride (NiMH)
5	Battery chemistry for Li-ion technology includes lithium cobalt oxide [LCO (LiCoO2)], lithium–nickel–manganese–cobalt–oxide [NMC (LiNixMnyCozO2)], lithium–manganese [LiMn (LiMnO2)], lithium iron phosphate [LFP (LiFePO4)]

lists the scope of PEFCR [29]. Product systems include mobility using electricity, information and communication technologies such as phones and computers, and cordless power tools such as drills and electric screwdrivers. In addition, batteries with lithium-ion technology were included in the product system but a PPS was not mentioned. However, as the subject of this study is a PPS based on nickel manganese cobalt (NMC) and lithium iron phosphate (LFP) battery systems, it was included in the scope of the PEFCR. Additionally, it was assumed that the parts recycled in the end-of-use/life stage replaced the new materials constituting the PPS, and the avoidance effect was calculated and deducted from the premanufacturing stage.

3.2. Selection of Methodology for Impact Assessment and Impact Category

Global warming potential (GWP) and abiotic depletion potential (ADP) were selected as environmental impact categories for this study, as shown in

Table 5. Environmental impact category and unit.

Impact Category	Unit
ADP (abiotic depletion potential)	kg Sb-eq.
GWP (global warming potential)	kg CO2-eq.

. It was found that the most significant environmental impacts occur during the pre-manufacturing and use stages. Components such as aluminum and batteries, known for high ADP and GWP during the raw material extraction stage and in the premanufacturing stage, were identified [30,31]. Additionally, in the use stage, the high GWP was attributed to the electricity consumption throughout the product’s lifespan. Consequently, the analysis concentrated on these two environmental impact categories.

4. Economic Benefits Analysis Methods

In this study, we estimated the economic benefits of remanufacturing businesses. As shown in Equation (2), the economic benefit of the waste battery remanufacturing business sector was calculated by subtracting sales revenue (A) from the waste battery pack purchase cost (B1) and operating cost (B2) of the remanufacturing process. The revenue from the sale of the remanufactured products (A) was calculated by multiplying the annual sales volume of the PPS by the sales price. The cost of purchasing the waste battery pack (B1) was multiplied by the purchase cost and the annual number of battery pack purchases. The operating cost of the remanufacturing process (B2) was calculated by adding the annual labor, waste purchase, distribution, and management costs. The costs and benefits were calculated based on the values generated in the Republic of Korea, and the values were derived using the 2022 average exchange rate of KRW/USD 1291.95.

$$C=A-(B1+B2)$$

(2)

$C$: economic benefits of spent battery remanufacturing (USD/year);

$A$: revenue from sale of remanufactured goods (USD/year);

$B1$: purchasing cost of spent battery pack (USD/year);

$B2$: operation cost of the remanufacturing process (USD/year).

5. Results

5.1. Setting Targets and Scope

The targets of this study were RPPS and NPPS. The RPPS is a 2 kW capacity product of Company G, which was remanufactured from three cells of a waste EV lithium-ion battery. For comparison, the NPPS is a 2.5 kW capacity product of Company A (Shenzhen, China) imported from China that uses a lithium iron phosphate battery. The reason for selecting LFP battery packs as a comparison is due to their widespread use in the market, where they are favored for their cost-effectiveness. The purpose of the product is to supply temporary power for using electric devices in emergency situations, e.g., when the power supply is interrupted or electricity is limited, such as outdoors [32], and the functional unit is one product. Considering the capacity difference between the RPPS and NPPS, the NPPS was converted based on a weight of 2 kW. Figure 3 shows the components of the product.

5.2. System Boundary

In both RPPS and NPPS, the premanufacturing, manufacturing, distribution, use, and end-of-use/life stages of the product are considered. At the end-of-use/life stage of the NPPS system boundary, the process involves sending reusable parts to the manufacturing stage of the RPPS system boundary for reuse/remanufacturing. The remaining components are divided into material recycling or landfill/incineration. The system boundaries of the product are illustrated in Figure 4.

5.3. Data Collection and Calculation

5.3.1. Premanufacturing

A summary of the weights and materials of each component constituting the RPPS and NPPS is presented in

Table 6. Product bill of materials (BOM) based on functional unit.

BOM	RPPS			NPPS
	Item	Weight (kg)	Material	Item	Weight (kg)	Material
Input	Battery cell	9	Anode (NMC) Cathode (carbon) Copper Aluminum Electrolyte Separator (polypropylene)	Battery cell	10.27	Anode (LFP) Cathode (carbon) Copper Aluminum Electrolyte Separator (polypropylene)
	Housing	4	Aluminum	Housing	4.57	Aluminum
	Controller	0.6	Printed circuit board (PCB)	Controller	0.68	PCB
	High-voltage parts, such as busbar/wiring	0.8	Bronze, iron	High-voltage parts, such as busbar/wiring	0.91	Bronze, iron
	Charger	2.5	Aluminum	Charger	2.85	Aluminum
	Carry bag	1.5	Nylon	Packaging box	0.8	Cardboard
	Packaging box	0.7	Cardboard
	Filling materials	0.1	Polypropylene	Filling materials	0.11	Polypropylene
	Instruction manual	0.2	Paper	Instruction manual	0.23	Paper
Output	RPPS 1 set	19.4	Mixture	NPPS 1 set	20.43	Mixture

. The calculated total weight of the RPPS was 19.4 kg and that of the NPPS was 20.43 kg. Most items making up the product were the same; however, the carrier bags were not included in the NPPS, and the materials making up the battery cell differed.

5.3.2. Manufacturing

When a PPS is manufactured, electricity is predominantly used for operating a battery performance tester. When 1000 units of the RPPS were produced, the electricity consumption was 9000 kWh, and the result of converting this per-product standard was an electricity consumption of 9 kWh. As collecting data was difficult, the electricity consumption during the production of the NPPS was assumed the same as that for producing the RPPS.

5.3.3. Distribution

The transportation distances by region from the metropolitan area where the RPPS manufacturing plant is located to various delivery regions are listed in

Table 7. Distribution scenario of RPPS.

Departure	Arrival	Transportation Distance (km)	Transportation Method	Number of Units Sold per Year
Seoul Metropolitan Area (Seoul)	Seoul Metropolitan Area (Seoul)	30	Truck	499
	Gangwon-do (Won-ju)	125		37
	Chung-cheong bukdo (Cheongju)	138		43
	Chungcheongnam-do (Daejeon)	161		73
	Jeollabuk-do (Jeonju)	212		27
	Jeollanam-do (Gwangju)	212		66
	Gyeongsangbuk-do (Daegu)	288		106
	Gyeongsangnam-do (Busan)	395		124
	Jeju	709	Ship, truck	25

. The table also shows the corresponding sales figures for each region, considering an annual sales volume of 1000 units. The products are primarily transported by trucks between different regions, but Jeju Island transportation is a combination of trucks and maritime shipping. The average transport distance per RPPS product was calculated to be 146.38 km as described in

Table 8. Average transport distance of RPPS.

Average Transport Distance (km)	Number of Units Sold
146.38	1

. The consumer distribution for the NPPS was assumed the same as that of the RPPS.

The transport scenarios for NPPS imports are shown in

Table 9. Import scenario of NPPS.

	Departure	Arrival	Transportation Distance (km)	Transportation Method
Route 1	Manufacturer of portable power station (China, Shenzhen)	Port (China, Shenzhen)	20	Truck
Route 2	Port (China, Shenzhen)	Port (Republic of Korea, Incheon)	2267	Ship
Route 3	Port (Republic of Korea, Incheon)	Supplier (vendor) of portable power station (Republic of Korea, Seoul)	20	Truck
Total	-	-	2307	-

. The process of importing products is shown in three routes, considering the distance from the product manufacturer in China to the Chinese shipping port, from the Chinese shipping port to Incheon Port in the Republic of Korea, and from Incheon Port to the NPPS vendor. The total import distance of the NPPS was estimated to be 2307 km. For the truck transport route, the distance was calculated by searching Google Maps, and the distance provided by Netpas was used for the transport route to the port [33].

5.3.4. Use

Power is the utility used in the use stage to charge the PPS. The amount of power used during PPS charging was calculated using the product life, number of camping events, number of car camping events, power consumption, and charging time of the product for a single charge.

The power consumption of the RPPS was calculated using the dataset provided by Company G, setting the power consumption per charge to 1 kW, the time required for a single charge to 20 h, and the lifespan to 10 years. That of the NPPS was calculated using data provided on the sales website, setting the power consumption per charge to 1.26 kW, the time required for one charge to 33 h, and the lifespan to 10 years. In addition to information on product lifespans provided by the company, according to Philippot et al. [6], the repurposed duration should be limited to 10 years, owing to potential safety concerns.

For annual charging, the statistical data of the annual average number of camping and car camping events [28] were used. A PPS is intended to be used in emergency situations when the power supply is interrupted; however, as it is difficult to quantify such cases, its usage was limited to outdoor and leisure activities. Therefore, the use and charging of the PPS were based on the rounded number of camping/car camping events in 2020 derived from statistical data.

Table 10. Average number of camping events and car trips per year in Republic of Korea.

Year	2018	2019	2020
Average number of camping trips per year	3.6	3.8	5.1
Average number of car camping trips per year	-	-	2.8

shows the average annual number of camping events and car trips in the Republic of Korea. In this study, the assumed average annual number of camping and car camping events in 2020 were five and three, respectively, and charging of the PPS was set to eight times a year.

For leisure events, the calculated power consumption results were 160 kWh for RPPS and 264 kWh for NPPS when the PPS was used and charged eight times a year and eighty times over a total life span of 10 years.

5.3.5. End-of-Use/Life

According to Annex 12 of the revised EU Battery Directive (Directive 2006/66/EC) [29], the objective for the recycling rate of batteries based on lithium is 70% by 2030. The recycling rates of the system included in the PEFCR battery are listed in

Table 11. End-of-use/life scenario in EU to be applied in the product environmental footprint (PEF) declaration [29].

Waste Treatment	CPT + ICT	E-Mobility
Collection for recycling	45%	95%
Unidentified stream	30%	5%
Landfill	16%	-
Incineration	9%	-

. The recycling rate of PPSs was assumed to be 75% by adding 45%, which is the recycling rate of cordless power tools (CPTs) + information and communication technology (ICT), and 30%, which is an unidentified stream. In addition, 16% of the product would go to landfills, and 9% would be incinerated. As the battery cells of the RPPS were reused batteries, the environmental impact of disposing the battery cells was zero. Recycling, landfill, and incineration rates were applied for the packaging materials, using statistical data from the Ministry of the Environment of the Republic of Korea [34].

5.4. Applied Life Cycle Inventory Databases (LCI DBs)

The life cycle inventory databases (LCI DBs) used in this study are listed in

Table 12. Applied life cycle inventory databases (LCI DBs).

List	LCI DB
	Name	Reference
Anode	Anode production and graphite for Li-ion battery, China (CN)	Ecoinvent 3.8 [35]
Cathode	Carbon black	KEITI (2022) [36]
Copper	Copper	KEITI (2022) [36]
Electrolyte	Electrolyte production for Li-ion battery, global (GLO)	Ecoinvent 3.8 [35]
Aluminum	Aluminum alloy production	KEITI (2022) [36]
PCB	Hard-printed circuit board	KEITI (2022) [36]
Bronze	Bronze production, rest of world (RoW)	Ecoinvent 3.8 [35]
Iron	Sponge iron production, rest of world (RoW)	Ecoinvent 3.8 [35]
Nylon	Nylon 6-6 production, rest of world (RoW)	Ecoinvent 3.8 [35]
Cardboard	Cardboard	KEITI (2022) [36]
Polypropylene	Polypropylene	KEITI (2022) [36]
Paper	Printed paper	KEITI (2022) [36]

. The Korean national LCI DBs and the Ecoinvent database are used in this study.

5.5. Environmental Impact Assessment of RPPS and NPPS

The results of the LCA and the contribution analysis of the RPPS are listed in

Table 13. Analysis of contribution and life cycle environmental impact of RPPS.

	Pre-Manufacturing	Manufacturing	Distribution	Use	End of Use/Life	Total
ADP (kg Sb-eq.)	3.72 × 10−1	2.82 × 10−2	3.49 × 10−3	5.01 × 10−1	1.05 × 10−2	9.15 × 10−1
	40.7%	3.1%	0.4%	54.7%	1.1%	100%
GWP (kg CO2-eq.)	4.81 × 101	4.46 × 100	5.52 × 10−1	7.92 × 101	1.88 × 100	1.34 × 102
	35.9%	3.3%	0.4%	59%	1.4%	100%

. The environmental impact was highest in the order of use, premanufacturing, manufacturing, end-of-use/life, and distribution stages. The use stage had the highest environmental impact owing to the amount of power consumed for charging during the 10-year lifespan of the product, with ADP accounting for 54.7% and GWP for 59.0%. In the premanufacturing stage, all components comprising the RPPS used new products, except for battery cells; therefore, the environmental impact was relatively high. However, the NPPS used a new battery, whereas the RPPS used a remanufactured battery; therefore, the environmental impact was relatively small. In the manufacturing stage, only the power consumption for the operation of the battery performance tester was considered. Therefore, a relatively low environmental impact was derived, and the same values were derived for both the RPPS and the NPPS. The environmental impact is expected to increase if the data are reflected through data collection and allocation to other utilities in the manufacturing stage in the future. In the use stage, a difference occurs in the charging time; however, the charging time of the RPPS is shorter than that of the NPPS, resulting in a lower environmental impact. The disposal stage has a relatively low environmental impact, owing to the high recycling rate of the product. In the distribution stage, the environmental impact was low because of the light weight and short transportation distance of the product.

A summary of the LCA and contribution analysis findings for the NPPS is provided in

Table 14. Contribution analysis and life cycle environmental impact of NPPS.

	Pre-Manufacturing	Manufacturing	Distribution	Use	End of Use/Life	Total
ADP (kg Sb-eq.)	6.97 × 10−1	2.82 × 10−2	6.87 × 10−3	8.26 × 10−1	1.90 × 10−2	1.58 × 100
	44.2%	1.8%	0.4%	52.4%	1.2%	100%
GWP (kg CO2-eq.)	9.22 × 101	4.46 × 100	1.01 × 100	1.31 × 102	2.73 × 100	2.31 × 102
	39.9%	1.9%	0.4%	56.6%	1.2%	100%

. The environmental impact was highest in the order of premanufacturing, use, manufacturing, disposal, and distribution stages based on ADP and highest in the order of use, premanufacturing, manufacturing, disposal, and distribution stages based on GWP. In the premanufacturing stage, the NPPS had a higher environmental impact than the RPPS because all the parts were new. The use stage had a high environmental impact owing to the influence of the power consumption of charging for the 10-year lifespan of the product. In the manufacturing stage, only the power consumption for the operation of the battery performance tester was considered; therefore, a relatively low environmental impact was derived. If it were possible to collect data on other utilities that would be included in NPPS manufacturing in the future, the environmental impact of the manufacturing stage would differ. The disposal stage had a relatively low environmental impact because of the high recycling rate of the product. The distribution stage had the lowest environmental impact, attributable to the light weight of the product, despite the relatively long transport distance, as the product had been imported from China.

The total environmental impact of one product and the environmental impact comparison results of NPPS and RPPS are shown in

Table 15. Comparison of the environmental evaluation results for RPPS and NPPS.

	RPPS	NPPS	Environmental Impact Reduction	Reduction Rate (%)
ADP (kg Sb-eq.)	9.15 × 10−1	1.58 × 100	6.63 × 10−1	42.01%
GWP (kg CO2-eq.)	1.34 × 102	2.31 × 102	9.68 × 101	41.91%

and Figure 5. The ADP showed a decrease of 42.01% in the RPPS compared with that in the NPPS, and a decrease of 41.91% in GWP compared with that of the NPPS. In this respect, Lee et al. [37] also indicated that among the environmental impact factors associated with the remanufacturing of turbochargers, the most significant effects were the reductions in GWP and ADP.

5.6. Economic Benefits Induced by Remanufactured Portable Power Stations

In this study, economic benefits were analyzed by calculating the annual costs and benefits of producing RPPSs by remanufacturing batteries from EVs. Labor, waste purchase, distribution, and management costs, i.e., the remanufacturing process costs, were investigated and calculated as annual costs. Those cost data were collected from Company G. Regarding benefits, the annual benefits generated by the remanufacturing business were calculated considering the sales volume and price of an RPPS. The economic benefits of the spent battery remanufacturing business sector were also calculated.

Table 16. Operating expenses of remanufacturing process (unit: USD).

List	Cost Incurred in the Process of Disassembly of One Pack	Production Cost of One Product	Production Cost of 1000 Products
Labor cost	1238.438	-	38,392
Distribution cost	-	270.908	270,908
Administrative expenses	-	154.805	154,805

shows a list of labor, distribution, and management costs, which constitute the operational expenses of the remanufacturing process for a single product. Additionally, the costs for labor and management are calculated for the sale of 1000 products per year. When producing 1000 products, labor costs were USD 38,392, distribution costs were USD 270,908, and administrative expenses were USD 15,480. Therefore, the total operating expense of the remanufacturing process is USD 464,105.

The sale price of a single product, along with the yearly sales revenue from 1000 units, is provided in

Table 17. Annual sales revenue based on 1000 product units (unit: USD).

Sales Amount per Remanufactured Product	Annual Sales Revenue Based on 1000 Product Units
1153	1,153,295

. The sales revenue of RPPS products is USD 1153 per unit and USD 1,153,295 for 1000 units sold.

The calculated economic benefit of remanufacturing waste batteries was USD 593,312, assuming annual sales of 1000 units, as shown in

Table 18. Economic effects of annual remanufactured product sales (unit: USD).

Product Sales Revenue (A)	Cost of Purchasing Used Battery Pack (B1)	Operating Expenses of Remanufacturing Process (B2)	Economic Benefits (C = A − (B1 + B2))
1,153,295	95,979	464,105	593,212

.

6. Conclusions

In this study, an environmental and economic assessment of a remanufactured portable power station (RPPS), compared to those of a new portable power station (NPPS), using a life cycle approach is presented. The materials and associated inventory data for all the components were obtained from commercial PPS vendors. The methodology provided dependable outcomes with respect to the environmental enhancements stemming from utilizing remanufactured electric vehicle (EV) products and enhanced the accuracy of the inventory data.

We analyzed the environmental effects of an NPPS and RPPS. The environmental properties of the NPPS and RPPS were compared using the life cycle assessment (LCA) method, with the following results. The LCA results for the RPPS reusing EV batteries indicated the introduction of environmental impacts characterized by an abiotic depletion potential (ADP) of 9.15 × 10⁻¹ kg Sb-eq. and a global warming potential (GWP) of 1.34 × 10² kg CO₂-eq. These figures for NPPS were an ADP of 1.58 × 10⁰ kg Sb-eq. and a GWP of 2.31 × 10² kg CO₂-eq. The analyses showed that the environmental advantages of the RPPS were a 42.01% reduction in ADP and a 41.91% reduction in GWP compared with those of the NPPS. Notably, both products registered their most significant environmental impacts during the premanufacturing and use phases.

The computed economic benefits of the waste battery remanufacturing business were USD 593,212 considering an annual sales volume of 1000 units.

The anticipated outcomes of this study can be applied to the revitalization of associated industries, including battery recycling and reuse and the preparation of institutional devices. This significance is particularly pronounced as the volume of waste EV batteries is increasing in the burgeoning EV market. Furthermore, these results are projected to positively impact the prospective growth of the PPS and battery remanufacturing product markets by leveraging discarded EV batteries. As a follow-up study, precise values could be derived by securing data from companies for some of the assumptions made in this study to facilitate more precise assessment.