이차전지의 폐자원흐름 분석 및 자원순환성 제고방안

조지혜 ( Ji Hye Jo ),주현수,이소라,김유선 한국환경정책평가연구원 2017 기본연구보고서 Vol.2017 No.-

이차전지란 한 번 사용하고 버리는 일차전지와는 달리 외부의 전기에너지를 화학에너지의 형태로 전환시켜 충·방전이 가능한 전지를 의미한다. 니켈카드뮴전지, 연축전지 등 이차전지의 종류는 다양하나 이 중 리튬이차전지는 스마트폰을 비롯해 블루투스, 드론, 전기차 (EV), 에너지저장장치(ESS) 등에 폭넓게 활용되어 오늘날 전지 시장을 주도하고 있다. 리튬 이차전지 시장은 스마트폰의 상용화를 통해 시장 입지를 다졌으며, 최근 전기차의 급속한 보급과 ESS의 등장에 힘입어 시장규모가 크게 확대되고 있다. 이처럼 급성장하는 이차전지 시장의 속도에 상응하여 효용 만료 및 폐기 등을 통해 폐배터리의 형태로 그 배출 또한 급증할 것으로 전망된다. 하지만 현재 리튬이차전지가 폐기된 이후의 회수 및 관리체계가 미흡한 상황이다. 생산자 책임재활용제도(EPR) 대상 배터리는 수은전지, 산화은전지, 리튬일차전지, 니켈카드뮴전지, 망간/알칼리망간전지, 니켈수소전지만을 대상으로 하고 있어 리튬이차전지는 관리의 사각지대에 있다. 특히 보조배터리, 전기차용 및 ESS용 폐배터리 등은 배출 이후 관리체계 및 처리 가이드라인이 부재한 상황이다. 또한 폐리튬이차전지는 잘못 관리될 경우 폭발 위험성이 높기 때문에 수송 및 처리에 있어 안전성이 요구된다. 현재 리튬이차전지 내 유가금속의 가격이 수요 확대로 인해 급격히 상승하고 있다. 희유 금속인 코발트와 리튬은 양극활물질의 주요 성분으로, 양극활물질은 소재 원가의 40% 상당을 차지하는 핵심 소재이다. 국내 이차전지 업계에서는 코발트와 리튬을 전량 수입에 의존하고 있는 상황으로 국제 유가금속 가격 상승에 매우 취약한 상황이다. 이에 폐리튬이차전지의 자원순환 체계 마련을 통해 유가금속을 효율적으로 회수 및 확보할 수 있도록 정책적으로 지원할 필요가 있다. 해외에서는 자원 회수 및 안전성에 대비한 폐리튬이차전지의 관리체계 구축 및 재활용기술 개발이 활발히 진행되고 있다. 하지만 국내의 경우 리튬이차전지가 배출된 이후 관리흐름에 대한 연구조차 미미한 상황이다. 이에 본 연구에서는 리튬이차전지의 폐자원흐름 분석을 통해 관리현황 및 체계를 파악하고 재활용을 저해하는 문제점을 분석하여 이에 대한 개선방안을 제시하고자 한다. 이를 위해 소형(휴대폰 폐배터리)/중형(전기차 폐배터리)/대형(ESS 폐배터리)을 대상으로 각각 배출단계, ②수거단계, ③전처리단계, ④자원회수단계, ⑤활용단계에 이르는 단계별 흐름을 파악하였다. 또한 향후 발생량 전망을 통하여 희유금속 회수에 따른 수입대체 효과를 산정하고 자원순환성 제고를 위한 배출-수거-전처리-자원회수의 관리기반을 마련하였다. 먼저 소형(휴대폰 폐배터리)의 경우 배출형태는 일체형과 분리형으로 나눌 수 있다. 일체형은 휴대폰에 내장된 채 배출되는 리튬이차전지로 주로 가정에서 배출되며, 휴대폰 유통 및 생산업체에서 배출되는 양은 상당히 미미하다. 가정에서 배출되는 폐휴대폰(폐배터리 포함)은 주로 9가지의 경로 - 새 제품을 구매하는 곳(이동통신사 대리점, 이하 대리점), 캠페인, 상시수거, 위탁회수, 한국정보통신진흥협회(KAIT), 대형마트, 우체국, 민간수집, 중고거래 - 에 해당하는 것으로 나타났다. 이 중 캠페인, 상시수거, 위탁회수, 한국정보통신진흥협회(KAIT) 등에서 회수되는 폐휴대폰은 한국전자제품자원순환공제조합(이하 공제조합)에서 관리되고 있다. 공제조합에서 취합한 폐휴대폰은 수도권자원순환센터(MERC)로 운송되어 본체에서 폐배터리를 분리한 후 이를 재활용업체에 판매하고 있다. 한편, 대리점에서는 중고휴대폰을 구매하여 민간 알뜰폰 사업자(MVNO: Mobile Virtual Network Operators)에게 임대폰으로 판매하거나 해외로 수출하는 것으로 알려져 있다. 공제조합 실무자와의 인터뷰에 따르면, 배출된 전체 폐휴대폰 중 약 98%가 수출되고 있는 것으로 파악된다. 그 밖에도 대형마트, 우체국 역시 최종소비자로부터 일정 금액을 지급하여 중고폰을 구입한 후, 민간업자에게 판매하는 것으로 조사되었다. 수집업체는 사업자 혹은 협회 (한국중고통신유통협회 등)로 나뉘며, 각 기관에서는 민간 대리점, 대형마트, 우체국 등을 통해 수거된 중고 휴대폰을 수출하거나 중고시장에서 거래하고 있다. 중고거래는 전자상거래의 형태로 C2C (Customer to Customer) 혹은 C2B (Customer to Business) 등으로 이루어지고 있다. 한편, 분리형의 경우 배출 및 수거 방식 등에서 일체형과 다른 형태를 지닌다. 배출 주체는 사업장과 수입으로 분류되며, 배터리 제조업체에서 공정 중 부산물의 형태로 배출되거나 미국, 호주, 말레이시아 등에서 분말 및 폐배터리 형태로 수입되고 있다. 중고제품으로 팔리거나 공제조합 등에서 회수하고 있는 일체형과 달리, 분리형은 바로 재활용업체로 운송되어 재활용된다. 수입의 경우 일부 폐배터리는 수입업체를 통해 국내에 반입되어 재활용업체로 운송되며, 나머지 폐배터리 및 분말은 재활용업체에서 직접 수거하고 있다. 재활용업체로 운송된 폐리튬이차전지는 전처리 및 자원회수 공정을 거치게 된다. 이는 소형뿐만 아니라 전기차용 및 ESS용 폐배터리 등 다른 제품 유형의 리튬이차전지에도 동일하게 적용된다. 전처리단계에서는 원료 투입-파쇄-입도분리-자력선별-리튬전지 화합물 회수를 통해 수거된 폐전지를 파쇄해서 분말 형태로 만드는 과정이며, 자원회수 공정에서는 분말로부터 침출-여과-저장-추출의 과정을 통해 코발트, 황산망간, 니켈, 인산리튬, NMC파우더 등을 회수할 수 있다. 추출된 유가금속 중 망간, 코발트, 리튬 등은 결정화 단계를 거쳐 메탈종류로 생산되며, 인산리튬은 탄산리튬 생산 공장을 거쳐 최종적으로 탄산리튬으로 전환 및 생산된다. 이렇게 회수된 유가금속(코발트, 황산망간, 니켈, 인산리튬, 탄산리튬, NMC 파우더)은 전구체 업체, 합금 제조업체, 활물질 제조업체 등에 판매된다. 코발트의 일부는 타이어 관련제품 제조업체에도 납품되고 있다. 다음으로 중형(전기차 폐배터리)의 경우에도 각 단계별로 관리현황을 조사하였다. 국내배출은 ①개인, ②기관, ③사업체, ④제조사 등으로 구분된다. 전기차 소유주는 개인을 의미하나, 현재 국내에서 판매되는 전기차 대부분은 정부 및 지자체 보조금을 받고 있기 때문에 전기차 배터리는 지자체 소유로 구분된다. 기관이란, 공공기관에서 구매한 전기차량을 의미하며, 사업체는 버스회사를 뜻하는 운수업체, 전기택시업체, 렌터카업체, 배터리리스 사업체 등 4가지 유형으로 구분된다. 한편, 폐배터리 형태로 배출되는 분리형은 배터리 제조사와 완성차 제조사에서 주로 공정 중에 발생한다. 소형 배터리와는 달리, 전기차 배터리는 팩 상태로 출시되기 때문에 배터리팩 해체작업이 필요하며, 이는 수작업으로 진행되고 있어 현재는 제조사에서 재활용업체에 처리비용을 지불하고 처리하고 있다. 국내외적으로 전기차 보급이 급격히 늘어갈 것으로 전망되는 가운데, 전기차 배터리 역시 2020년까지 약 200억 달러 시장을 형성하며 크게 성장할 것으로 예측된다. 전기차 배터리는 각 형태에 따라 용량이 다르나, 휴대폰 배터리 기준으로 4,300개의 배터리 용량에 해당한다. 본 연구에서 전기차 폐배터리의 발생량을 추정한 결과, 2017년에는 3대에 불과하나 2025년에는 8,321개의 폐배터리가 발생할 것으로 예측되며, 이는 1,976톤에 해당하는 수치이다. 하지만 현재 「대기환경보전법」에 따라 보조금이 지급된 전기차의 경우 폐차 혹은 수출 등 말소 시 해당 폐배터리를 지방자치단체의 장에게 반납하도록 하고 있으나, 그 이후의 관리체계가 마련되어 있지 않아 현장에서는 혼선을 빚고 있다. 또한 전기차 폐배터리의 경우 발화 및 폭발 가능성이 높아 안전성에 대한 위험성이 지속적으로 제기되고 있으나, 이를 고려한 안전취급 지침 역시 부재한 실정이다. 이에 본 연구에서는 보조금 지급/미지급을 구분하고, 폐차 및 수출 등으로 말소되는 경우 이외에도 운행 중인 전기차 배터리에 대해 한계 효용에 도달했다고 소비자가 판단하는 경우, 교통사고 발생으로 파손의 우려가 있는 경우 등 크게 4가지 사항으로 구분하여 관리체계(안)을 마련하였다. 대형(ESS 폐배터리)의 경우에도 정부로부터 ESS 설치 지원 혹은 전력요금 감면 등을 통하여 보조금이 지급되고 있으나, 이 역시 전기차 폐배터리와 마찬가지로 관리체계가 아직 구축되어 있지 않은 상황이다. 현재 개인 배출 ESS는 주로 가정용 ESS 형태로 배출될 수 있으나, 아직까지 국내 가정용 ESS 보급률은 상당히 낮은 상황이다. 기관의 경우 주로 공공기관에서 사용하고 있으며, 사업체의 경우에는 UPS나 발전소 등에서 주로 사용된다. 지금까지는 ESS 폐배터리의 발생량이 없으나 향후 발생할 경우 지정업체를 통해 수거될 것으로 예상된다. 또한 LG화학, 삼성SDI, 코캄, 인셀, 탑전지 등 ESS 제조사에서 공정 부산물로 발생된 폐배터리 역시 향후 배출 시 재활용업체로 바로 보내질 것으로 판단된다. 상기의 각 제품 유형별로 리튬이차전지의 폐자원흐름을 분석하여 관리상 문제점 및 개선방안을 도출하였다. 우선 소형 폐리튬이차전지(휴대폰 배터리 및 보조배터리 등)에 대해 살펴보면 다음과 같다. A rechargeable (secondary) battery is a battery which can be repeatedly charged by converting the external electric energy into a form of chemical one. Today, the secondary battery has been widely used in mobile phone, Electric Vehicle (EV), Energy Storage System (ESS), etc. However, there are several issues raised on how to manage these waste secondary batteries. Since the Extended Producer Responsibility (EPR) regulation only targets batteries made of mercury, silver-oxide, lithium primary, nickel-cadmium, manganese/ alkaline-manganese, and nickel-hydride, lithium secondary batteries have been untouched for waste management. Moreover, waste battery products like portable chargers, EV battery and ESS battery has no disposal process guideline. Considering the risk of explosion and the trend of increasing price of valuable metals (cobalt, nickel, lithium, etc.) used in the lithium secondary battery, it is necessary to build the safe management and effective resource circulation system. Therefore, we conducted the secondary material flow analysis for the waste lithium secondary batteries. With the analysis, we tried to understand the domestic system of waste lithium secondary battery and find out the bottlenecks in the process of recycling. Lastly, we suggested applicable and improved plans by forecasting the expected amount of the waste lithium secondary battery, and estimated the effect of import substitution by recovering the rare metals. For this work to be done, we set the scope of this study into small size (for mobile), medium size (for EV) and large size (for ESS) of the lithium secondary battery and traced the flow of waste lithium secondary battery in the aspect of 5 stages, which are disposal stage, collection stage, recycling stage, resource recovery stage and utilization stage. For the small size (for mobile) of the lithium secondary battery, the mobile phone battery is to be divided into two types: the battery equipped with the mobile phone and the battery itself. In the stage of the disposal, most of the mobile phones are discarded by household, distributor and manufacturer of the mobile phone. Most of the used mobile phones are collected in 9 routes which are: 1) store where customer purchases new mobile phone, 2) the public campaign, 3) the public permanent collection spot, 4) consignment collection, 5) Korea Association for ICT Promotion (KAIT), 6) large retailers, 7) Post office, 8) private collector and 9) private second hand dealers. After that, some batteries are sent to the recycling center under the management of Korea Electronics Recycling Cooperative (KERC) and 98% of used cell phones are assumed to be sold overseas. The latter one comes from the battery manufacturer or imported from the abroad such as U.S., Australia, and Malaysia, and is directly delivered to the recycling companies which is specialized in handling the waste lithium secondary battery. In the recycling stage, waste mobile phone battery is treated with two sub-processes: 1) preprocessing stage and 2) resource recovery. This recycling process is adapted to the all types of lithium secondary battery. After the preprocessing stage, some of the metals such as cobalt, oxide manganese, nickel and lithium are produced in the resource recovery stage. These recovered metals are sold to the precursor, alloy and cathode active materials manufacturer. Some portion of the recovered cobalt is provided to the certain manufacturer, related to tire products. For the medium size (for EV) of the lithium secondary battery, we also conducted the research on the flow of waste EV battery. EV battery is discarded by car owners, public sectors, business sectors and manufacturers. Most of the owners of EV receive subsidies from the both federal and local governments. Therefore, the battery installed in the vehicle belongs to the local government. Due to increasing EV sales in the global automobile markets, EV battery market is likely to grow in certain extent to the worth two billion by 2020. In this research, we can estimate the expected EV waste battery to be increased significantly to 8,321 by 2025 (which is equivalent to 1,876 ton). According to the 「Clean Air Conservation Act」, the waste batteries subsided by the government are returned to the local government head in the case of scraping or exporting the EV. However, there are no collecting and recycling schemes for the EV waste batteries. Considering the risk of the accidental explosion of the EV battery, we need to establish the safe and effective management system for the EV waste battery. For the large size (for ESS) of waste lithium secondary battery, we also find there are no sound wastes manage schemes in Korea. ESS sold in Korea has been subsided by the government in the forms of supporting the installation or discounting the electricity bill. The ESS waste battery is assumed to be discarded by the household and the public/private sector including the power plants. In these days, the waste batteries produced during the manufacturing process are sent to the recycling company directly. We expect that in few years, the batteries would be discarded by the public or private sectors and treated by authorized center for collecting and recycling the waste. Based on the secondary material flow analysis for each size of the lithium secondary battery, we point out the several management issues and propose the efficient safety strategies. We find five issues regarding on the small type of lithium secondary battery (mobile phone and portable charger) and also come up with four solutions in below. First, there are inaccurate statistical data indicating the domestic flow of mobile waste battery. After the end-users sell their used phones to the retailers, it is difficult to grasp all the detailed flow of them. It indicates that the small lithium secondary battery including portable charger, wireless vacuum cleaner is out of legitimate system. Second, we find that 54.5% of smart phone users still keep their used phones, and we assume that 24 million used-phones are stored at home. The collecting system is not the end-user friendly. Third, there is no safety guideline to collect and transport small lithium secondary battery. Without taping or discharging, explosion risks are considerable for the lithium secondary battery. Fourth, it is difficult to sort the lithium secondary battery into each type. The recycling companies have troubles in sorting the various types of the lithium secondary battery due to lack of the labels indicating the type of cathode active materials used. Lastly, it is necessary to improve the ‘Allbaro’ system to control the imported and exported lithium secondary battery. The level of importing the lithium secondary battery has been significantly increased by years and this is subject to the Basel Convention. This study suggests four solutions to the problems that are mentioned in above. The solutions are: 1) track back schemes by retailers which need to be expanded in the terms of scope and role. The retailers participating in the legitimate collecting program is only 2% of the mobile phone industry in Korea with the results of the low rate in collecting the mobile phone waste battery. In addition, they need to provide their consumer information of collecting the waste lithium secondary batteries, 2) existing legitimate municipal guidelines need to indicate what and how to discard the waste lithium secondary battery under the 「Act on Resource Circulation of Electrical and Electronic Equipment and Vehicles」. Therefore, small size of the waste lithium secondary battery including portable chargers can be safely treated and discarded by the household, 3) the label which symbolizing the type of cathode active materials needs to be attached to the battery itself, 4) the classification of battery type code needs to be modified by adding the specified waste code, in order to appropriately manage them in statistical terms. Next, this study looks into the result of secondary material flow analysis for the medium (for EV) and the large (for ESS) size of the lithium secondary battery and find three issues as well as ten solutions. The issues are: 1) there are no management systems for the EV waste battery. Even though「Clean Air Conservation Act」shows that the subsided EV battery should be returned to the local government head, there is no detailed instructions on collecting and recycling schemes and infrastructures, 2) there are no safe guideline of how to handle the EV waste battery. For many years, the risk of EV battery has been debatable in regard of explosion and low shock resistance, 3) it is difficult to disassemble the waste battery pack. All the bolt and nuts used in those products require hand work system since these are in different shapes depending on the manufacturers, and models of the products. Therefore, recycling companies have difficulty in dismantling those waste products in the recycling stage. In this study, the following 10 aspects of the management problems for EV and ESS waste batteries are examined. 1) Plans for establishment of management system for the subsidized EV waste battery are suggested in the cases ① when the consumer determines that the EV battery has reached its marginal utility, ② when there is a risk of damage due to car accidents, ③ when the registration of vehicle is cancelled by scrapping, and ④ when the owner cancels the registration of vehicle for the export as a used car. 2) There is a necessity of reorganized subsidy withdrawal standard by the characteristics of EV waste batteries. Although the same standard with the reduction devices is appled at present, it is necessary to set the recovery rate that distinguishes the characteristics and the value of the devices. 3) A plan for establishment of management system for the non-subsidized EV waste battery is also suggested, so that it can be also collected into the reuse/recycling system. 4) Establishment of Reuse Center (tentative name) for storage and performance inspection of the waste batteries is examined. The center's functions are collection, performance inspection, processing by inspection results, computerization and accounting. 5) Establishment of new statistical management system for the EV waste battery is needed to complement the missing data of current management system for EV and EV battery. 6) Establishment of legal basis for promoting the recycling of waste battery is reviewed by suggesting complementary measures(Articles) for 「Act on Resource Circulation of Electrical and Electronic Equipment and Vehicles」. 7) Safety guidelines for the control of waste batteries is reviewed for the safe transport and handling of the lithium secondary batteries in accordance with UN ADR(The European Agreement concerning the International Carriage of Dangerous Goods by Road). 8) There is a necessity of improvement standards and methods for ‘Designated Wastes’ by reflecting the characteristics of waste lithium secondary battery. 9) Establishment of the EV battery management department is needed for safe collection and providing relative information. 10) We suggest the safe management system for ESS and promote eco-design for the efficient recycling process. Furthermore, the establishment of cooperation system between battery pack manufacturers and recycling companies is needed for the development of easy-disassembling method for battery pack. The above-mentioned approaches for improvements can significantly contribute to the import substitution of valuable metals such as cobalt and lithium by developing the recycling system for waste batteries. In order to grasp the value of recovered valuable metals in detail, the study examined the import substitution effect of cobalt which has high economic effect. In 2027, estimated recoverable cobalt amounts for cell-phone are about 169 tons, 286 tons for EV and 234 tons for ESS, and the total amount is 689 tons. Based on the average value of imports over the past 5 years, the import substitution effect of cobalt recovered from waste batteries will be about 6% of imported amount in 2027 and about 15% in 2029. The import substitution effect will be significantly increased through the recovery of valuable metals from large waste batteries such as EVs in the near future. Therefore, the efficient resource circulation system for lithium secondary batteries should be established at the earliest passible moment, considering the domestic situation where 90% of minerals are heavily dependent on the imports and the rising prices of the valuable metals such as cobalt and lithium.

Stability and cycle performance of nonaqueous electrolytes in lithium air battery

김동욱 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

Lithium air batteries have now received increasing attention owing to the much higher theoretical energy density than the current state-ofthe- art lithium ion technology. Hence, lithium air batteries are considered as possible power sources for the next generation range-anxiety-free electric vehicles. However, recent tremendous research activities clearly revealed that there are many issues to be overcome such as high charge overpotential, fast capacity fading, low oxygen efficiency, etc. Since these critical problems are closely related with the nature of the used electrolytes, identification of stable electrolytes is the most important task for true rechargeable lithium air battery. Li-air battery is typically composed of lithium metal anode, organic solvent dissolved with lithium salt, and porous carbon cathode. During operation in the discharge and charge cycle, the reactive superoxide ion and lithium peroxide may attack the susceptible organic electrolyte, yielding several by-products such as lithium carbonate, lithium carboxylate, and lithium alkyl carboxylates. The side-products caused evolution of carbon dioxide and hydrogen rather than oxygen in charge as well as loss of capacity and cell failure. Many research groups all around world have tried to develop a stable electrolyte to suppress the side reaction and hence to enhance cycle performance in the cell. In the early stage, the carbonates such as propylene carbonate were used for the electrolytes. In-situ DEMS analysis and other spectroscopic tools have elucidated that the carbonates are susceptible to the nucleophilic attack by superoxide ion and are unsuitable for lithium air battery. After that, attention was shifted to many other solvents. Among them, so far ether-based solvents including TEGDME and DME, amide-based solvent such as DMA, and sulfoxide solvents such as DMSO are considered relatively stable against the harsh environment in lithium air battery operation. Our group also makes intense effort to develop desirable electrolytes by means of in-situ quantitative DEMS as well as other analytical instruments. In this talk, I will present and discuss the current research state on stability and cycle performance of the lithium air battery electrolytes.

자체 제작된 리튬이온 배터리팩의 과충전에 따른 화재위험성 연구

한용택,김일원,김시국 한국위험물학회 2022 한국위험물학회지 Vol.10 No.1

Lithium-ion battery packs are used in various electronic devices such as camping batteries, electric kickboard, and supplementary battery due to their high volumetric energy storage density. Recently, however, as more and more people make and use outdoor lithium-ion battery packs such as hiking, fishing, and camping, there is a battery fire while charging their own battery packs. This paper investigated the operating principle of these battery packs and conducted a study on the fire risk caused by overcharging in the presence or absence of lithium-ion batteries with the same capacity, lithium-ion batteries with different capacity, and PCM(Protection Circuit Module). As a result of the overcharging experiment, the battery pack was completely destroyed combustible gas and smoke generation near the lithium-ion battery anode of the battery pack without a protection circuit, followed by explosive combustion accompanied by flame. Vent and safety devices(PTC, CID) could be observed to have been lost due to overcharging explosion pressure.

Battery State Estimation Algorithm for High-Capacity Lithium Secondary Battery for EVs Considering Temperature Change Characteristics

Jinho Park,Byoungkuk Lee,Do-Yang Jung,Dong-Hee Kim 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

In this paper, we studied the state of charge (SOC) estimation algorithm of a high-capacity lithium secondary battery for electric vehicles (EVs) considering temperature characteristics. Nonlinear characteristics of high-capacity lithium secondary batteries are represented by differential equations in the mathematical form and expressed by the state space equation through battery modeling to extract the characteristic parameters of the lithium secondary battery. Charging and discharging equipment were used to perform characteristic tests for the extraction of parameters of lithium secondary batteries at various temperatures. An extended Kalman filter (EKF) algorithm, a state observer, was used to estimate the state of the battery. The battery capacity and internal resistance of the high-capacity lithium secondary battery were investigated through battery modeling. The proposed modeling was applied to the battery pack for EVs to estimate the state of the battery. We confirmed the feasibility of the proposed study by comparing the estimated SOC values and the SOC values from the experiment. The proposed method using the EKF is expected to be highly applicable in estimating the state of the high-capacity rechargeable lithium battery pack for electric vehicles.

패턴전사 프린팅을 활용한 리튬이온 배터리 양극 기초소재 Li₂CO₃의 나노스케일 패턴화 방법

강영림,박태완,박은수,이정훈,왕제필,박운익,Kang, Young Lim,Park, Tae Wan,Park, Eun-Soo,Lee, Junghoon,Wang, Jei-Pil,Park, Woon Ik 한국마이크로전자및패키징학회 2020 마이크로전자 및 패키징학회지 Vol.27 No.4

지난 수십년간 인류에게 핵심적인 에너지 자원이었던 화석연료가 갈수록 고갈되고 있고, 산업발전에 따른 오염이 심해지고 있는 환경을 보호하기 위한 노력의 일환으로, 친환경 이차전지, 수소발생 에너지 장치, 에너지 저장 시스템 등과 관련한 새로운 에너지 기술들이 개발되고 있다. 그 중에서도 리튬이온 배터리 (Lithium ion battery, LIB)는 높은 에너지 밀도와 긴 수명으로 인해, 대용량 배터리로 응용하기에 적합하고 산업적 응용이 가능한 차세대 에너지 장치로 여겨진다. 하지만, 친환경 전기 자동차, 드론 등 증가하는 배터리 시장을 고려할 때, 수명이 다한 이유로 어느 순간부터 많은 양의 배터리 폐기물이 쏟아져 나올 것으로 예상된다. 이를 대비하기 위해, 폐전지에서 리튬 및 각종 유가금속을 회수하는 공정개발이 요구되는 동시에, 이를 재활용할 수 있는 방안이 사회적으로 요구된다. 본 연구에서는, 폐전지의 재활용 전략소재 중 하나인, 리튬이온 배터리의 대표적 양극 소재 Li2CO3의 나노스케일 패턴 제조 방법을 소개하고자 한다. 우선, Li2CO3 분말을 진공 내 가압하여 성형하고, 고온 소결을 통하여 매우 순수한 Li2CO3 박막 증착용 3인치 스퍼터 타겟을 성공적으로 제작하였다. 해당 타겟을 스퍼터 장비에 장착하여, 나노 패턴전사 프린팅 공정을 이용하여 250 nm 선 폭을 갖는, 매우 잘 정렬된 Li2CO3 라인 패턴을 SiO2/Si 기판 위에 성공적으로 형성할 수 있었다. 뿐만 아니라, 패턴전사 프린팅 공정을 기반으로, 금속, 유리, 유연 고분자 기판, 그리고 굴곡진 고글의 표면에까지 Li2CO3 라인 패턴을 성공적으로 형성하였다. 해당 결과물은 향후, 배터리 소자에 사용되는 다양한 기능성 소재의 박막화에 응용될 것으로 기대되고, 특히 다양한 기판 위에서의 리튬이온 배터리 소자의 성능 향상에 도움이 될 것으로 기대된다. For the past few decades, as part of efforts to protect the environment where fossil fuels, which have been a key energy resource for mankind, are becoming increasingly depleted and pollution due to industrial development, ecofriendly secondary batteries, hydrogen generating energy devices, energy storage systems, and many other new energy technologies are being developed. Among them, the lithium-ion battery (LIB) is considered to be a next-generation energy device suitable for application as a large-capacity battery and capable of industrial application due to its high energy density and long lifespan. However, considering the growing battery market such as eco-friendly electric vehicles and drones, it is expected that a large amount of battery waste will spill out from some point due to the end of life. In order to prepare for this situation, development of a process for recovering lithium and various valuable metals from waste batteries is required, and at the same time, a plan to recycle them is socially required. In this study, we introduce a nanoscale pattern transfer printing (NTP) process of Li2CO3, a representative anode material for lithium ion batteries, one of the strategic materials for recycling waste batteries. First, Li2CO3 powder was formed by pressing in a vacuum, and a 3-inch sputter target for very pure Li2CO3 thin film deposition was successfully produced through high-temperature sintering. The target was mounted on a sputtering device, and a well-ordered Li2CO3 line pattern with a width of 250 nm was successfully obtained on the Si substrate using the NTP process. In addition, based on the nTP method, the periodic Li2CO3 line patterns were formed on the surfaces of metal, glass, flexible polymer substrates, and even curved goggles. These results are expected to be applied to the thin films of various functional materials used in battery devices in the future, and is also expected to be particularly helpful in improving the performance of lithium-ion battery devices on various substrates.

Battery State Estimation Algorithm for High-Capacity Lithium Secondary Battery for EVs Considering Temperature Change Characteristics

Park, Jinho,Lee, Byoungkuk,Jung, Do-Yang,Kim, Dong-Hee The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

In this paper, we studied the state of charge (SOC) estimation algorithm of a high-capacity lithium secondary battery for electric vehicles (EVs) considering temperature characteristics. Nonlinear characteristics of high-capacity lithium secondary batteries are represented by differential equations in the mathematical form and expressed by the state space equation through battery modeling to extract the characteristic parameters of the lithium secondary battery. Charging and discharging equipment were used to perform characteristic tests for the extraction of parameters of lithium secondary batteries at various temperatures. An extended Kalman filter (EKF) algorithm, a state observer, was used to estimate the state of the battery. The battery capacity and internal resistance of the high-capacity lithium secondary battery were investigated through battery modeling. The proposed modeling was applied to the battery pack for EVs to estimate the state of the battery. We confirmed the feasibility of the proposed study by comparing the estimated SOC values and the SOC values from the experiment. The proposed method using the EKF is expected to be highly applicable in estimating the state of the high-capacity rechargeable lithium battery pack for electric vehicles.

배터리 기술 발전 동향과 항공 우주 임무의 전기구동 시스템 (PART 1 : 리튬계열 배터리 및 전기추진 항공기 개발 동향)

김건영,이형진,김준겸,허환일 한국항공우주학회 2023 韓國航空宇宙學會誌 Vol.51 No.10

리튬은 낮은 밀도에 비해 단위 질량당 전기 용량이 높아 배터리의 에너지 성능을 크게 증가시켰다. 전력계의 경량화, 고효율 시스템을 구현하기 위해서는 리튬계열 배터리의 활용은 필수적이며, 항공 우주 분야는 배터리 기술 개발 트렌드에 빠르게 반응하기 때문에 배터리 종류별 특징을 이해하고 기술 개발 동향에 대한 사례 조사가 필요하다. 본 논문은 일ㆍ이차전지의 특성 및 차세대 전지와 전기추진 항공기에 대한 기술 개발 동향을 분석하였다. 차세대 이차전지에서는 리튬 금속의 음극 활용, 고체 전해질 기술이 배터리의 에너지 성능과 안정성을 향상시킬 수 있는 주요 기술로 파악된다. 항공 분야는 중ㆍ대형 항공기에 전기동력 추진 시스템을 적용하기 위한 기술 개발이 이루어지고 있으며, 차세대 전지가 적용된 비행 기술 시연 사례가 보고되고 있다. Lithium based battery, which has a high specific capacities, significantly improved battery performance. To implement a lightweight and high-efficiency power system, it is necessary to utilize lithium-based batteries. In addition, it is important to understand the characteristics of different types of batteries and the development trends of batteries, as the aerospace industry is rapidly adopting recent battery technologies. This paper analyzes the characteristics of each type of battery and the technology development trends for a next-generation battery and electrified aircraft were analyzed. In the next-generation secondary batteries, a lithium metal anode and a solid-state electrolyte are recognized as core technologies which can increase the energy performance and stability of batteries. The electrified aircraft technology is underway to apply to a medium and large sized aircraft. In addition, flight technology demonstration using a next-generation batteries is being reported.

Lithium-ion Stationary Battery Capacity Sizing Formula for the Establishment of Industrial Design Standard

Choong-koo Chang,Mumuni Sulley 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

The extension of DC battery backup time in the DC power supply system of nuclear power plants (NPPs) remains a challenge. The lead-acid battery is the most popular at present. And it is generally the most popular energy storage device. However, extension of backup time requires too much space. The lithium-ion battery has high energy density and advanced gravimetric and volumetric properties. The aim of this paper is development of the sizing formula of stationary lithium-ion batteries. The ongoing research activities and related industrial standards for stationary lithium-ion batteries are reviewed. Then, the lithium-ion battery sizing calculation formular is proposed for the establishment of industrial design standard which is essential for the design of stationary batteries of nuclear power plants. An example of calculating the lithium-ion battery capacity for a medium voltage UPS is presented.

A New Concept on Resources Circulation Policy for Electric Vehicles in Korea (Republic of)

( Yong Choi ),( Hyeong-jin Choi ),( Sueng-whee Rhee ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-

Globally, advanced countries will be prohibiting the sale of vehicles using internal combustion engine and promoting the supply of electric vehicles in order to reduce fine dust, air pollutants and carbon dioxide from vehicles. In Korea, 430,000 electric vehicles will be supplied by 2022 according to the atmospheric environmental policy. As the market for electric vehicles may be expanding at home and abroad, lithium ion secondary batteries from electric vehicles will be expected to be generated as wastes gradually. The lithium ion secondary batteries contain various valuable materials such as lithium, cobalt, manganese, nickel, iron, etc. According to Korea Mineral Resource Information Service (KOMIS), the price of lithium increased 2.1 times from 7,576 U$/ton in 2015 to 15,534 U$/ton in 2018. The price of cobalt increased 2.5 times from 28,613 U$/ton to 72,824 U$/ton during the same period. Therefore, it is industrially very economical that valuable materials are recovered from the lithium ion secondary battery. In advanced countries, various resources circulation policies are being used to recover and recycle lithium ion secondary batteries in electric vehicles. In the European Union and Japan, the lithium ion secondary batteries are managed by the Expanded Producer Responsibility (EPR) system and a recycling council was established to recycle the lithium ion secondary batteries continuously. Also, China announced regulations on the recycling of lithium ion secondary batteries for vehicles in 2015, strengthening resources circulation capacity for lithium ion secondary batteries. Electric vehicles are being promoted in Korea but the resources circulation policy for lithium ion secondary batteries is insufficient. In this study, the current status of resources circulation policy for lithium ion secondary batteries from electric vehicles in advanced countries is reviewed. In Korea, a new concept on the policy for the activation of resources circulation for lithium ion secondary battery should be introduced step by step including production, consumption, collection and recycling stage. The new concept of resources circulation policy can be applied in many fileds, including the securing of recycling technology, the construction of capacity build, and the establishment of management system such as EPR system.

공랭식 원통형 리튬-이온 배터리 팩의 공기 흐름 변화에 따른 냉각 시스템 성능에 관한 수치해석 연구

이서근(SeoKeun Lee),심창휘(ChangHwi Sim),김철호(Chul-Ho Kim) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11

친환경자동차인 전기자동차의 동력원으로 에너지 밀도가 높은 리튬-이온 배터리가 주목을 받고 있다. 리튬-이온 배터리는 낮은 자가 방전율과 양호한 내구 수명 등 많은 장점을 지니고 있는 반면 온도의 변화에 따라 배터리 셀의 효율이 변화되며 특정 환경조건에서는 열 폭주 현상이 발생하는 등 안전성 측면의 문제가 제기되고 있으며 배터리 셀의 효율적 냉각과 셀간 온도 밸런스가 중요한 문제로 대두되고 있는 상황이다. 본 연구에서는 21700모델의 원통형 리튬-이온 셀을 적용한 공냉식 배터리 팩 모델을 대상으로 냉각 유로방향에 따른 배터리 팩의 냉각 성능과 셀 간의 온도 밸런스 특성을 분석해 보았다. 일반적으로 리튬-이온 배터리 팩은 원통형 셀이 정방향으로 반복적으로 균일하게 반복 배열되는 형태를 유지하고 있으며 연구의 편의성을 위해 이중 일부인 배터리 셀 7개의 구조를 대상으로 발열량이 일정하다는 정상상태로 연구를 진행하였다. 정상상태의 열유동해석을 위해 상용 CFD코드인 영국 CHAM사의 PHOENICS(ver.2018)를 이용하였다. 주요 연구 변수로 냉각 공기의 흐름 방향과 유량 그리고 셀의 간격을 설정하였으며 배터리 팩의 냉각 성능과 셀의 온도 분포를 분석하여 셀간 온도 밸런스를 정성, 정량적으로 분석하였다. 배터리 간격은 총 8가지 경우로 분석하였으며 셀의 온도는 3곳을 기준으로 판단하였으며 온도차이가 확연한 구간을 중심으로 간격을 설정하였다. 온도 밸런스 측면에서 균일도는 배터리 길이방향이 8.86%, 직경방향은 15.43%로 길이 방향이 직경 방향에 비해 6.57%p의 균일도 차이를 보였다. 본 연구를 통해 유체의 흐름 방향과 배터리 셀 간격이 냉각 성능에 미치는 영향을 정량적으로 분석하였으며 적정한 간격과 흐름 방향을 제시함으로써 향후 리튬-이온 배터리 팩의 최적화 냉각 연구에 기여할 것으로 기대된다. Lithium-ion batteries with high energy density are drawing attention as power sources for electric vehicles, which are eco-friendly vehicles. Lithium-ion batteries have many advantages, such as low self-discharge rates and good durable life, while the efficiency of battery cells varies depending on temperature and the heat explosion occurs under certain environmental conditions, raising safety issues. Therefore, efficient cooling of lithium-ion battery cells and temperature balancing between cells are becoming important issues. In this study, the cooling performance of battery packs along the flow direction and the temperature-balancing characteristics between cells were analyzed in the air-cooled battery pack models with cylindrical lithium-ion cells of 21700 models. In general, lithium-ion battery packs were studied in a steady state that the cylindrical cells were kept in a uniform, repetitive arrangement in the forward direction and that the heat value was constant in seven structures of battery cells, which are part of a pack, for the convenience of the study. A general purpose CFD simulation program named PHOENICS (ver. 2018) which is developed by CHAM, England was used. The flow rate, direction and spacing of cooling air and battery spacing were set as major research variables, and the cooling performance of battery pack and temperature distribution of cells were analyzed in a qualitative and quantitative analysis of temperature balancing between cells. The effect of battery space was analyzed with a total of eight cases, and the temperature was determined based on three points of cells. The interval was set around the area where the temperature difference was evident. In terms of temperature balance, the uniformity was 0.83% in the direction of battery height and 15.43% in the direction of diameter, showing 14.6% difference in between. Through this study, it is expected to contribute to the study of battery pack cooling by quantitatively analyzing the flow direction of fluid and the effect of battery cell space on cooling performance.