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<2024> 4680 배터리 기술개발동향 및 전망

 

4680 대형 원통형 배터리의 건식전극공정(DBE)을 위하여 Tesla는 Maxwell Technologies를 인수한 적이 있었으며, 건식전극공정은 건조에 필요한 에너지가 적고, 건조 과정을 위한 공장의 footprint 공간이 적으며, 생산 비용이 낮은 특징을 가지고 있다. 건식 코팅 공정을 양극까지 적용시킬 수 있다면 큰 가격 인하로 이어지며 EV업체나 제조업체가 win-win 할 수 있는 기술이다. 이와 같이 건식전극공정은 Tesla의 4680 제조 기술 중 하나이며, 4680제조를 위해 도입한 여러 기술이 구현된다면 Tesla는 전체적으로 56%의 코스트 다운이 가능할 것으로 예상되고 있다.

 

Tesla는 현재 Model Y와 Cybertruck을 제작하고 있는 텍사스 오스틴의 Gigafactory에서 건식 코팅 전극을 사용하는 4680 셀을 생산하고 있다. 알려진 바에 따르면 Tesla는 생산 목표를 달성할 수 있을 만큼 빠르게 4680 셀을 만드는 데 필요한 규모로 건식 코팅 공정을 아직 완료하지 못했지만, Panasonic, LG, CATL, EVE, BAK, SVOLT 등 많은 업체들이 4680 개발 및 양산에 뛰어들었으며, BMW, Daimler, Apple, Lucid, Rivian, Xiaopeng, NIO, FAW(디이자동차), JAC Motors 등이 4680 배터리 탑재를 발표하는 등 4680 열풍이 전 세계적으로 불붙고 있다.

 

SNE Research의 전망에 따르면, xEV 4680 수요는 25년 약 72GWh, 30년에 약 650GWh로 전망하고 있으며, Tesla의 경우 25년 약 80GWh, BMW의 경우, 25년 약 59GWh, 기타 업체의 경우, 25년 약 44GWh가 탑재될 것으로 전망된다.

 

그렇다면, 건식 코팅 공정의 어려움에도 불구하고, 4680 셀을 적용하려는 이유는 무엇인가? 아래에 4680의 뛰어난 장점을 열거해 본다.

 

(1)고에너지밀도: 4680셀의 용량은 2170셀의 5배, 외형만 변경되며 에너지밀도는 10% 증가

가능하며, Si/C 음극을 사용하면 에너지밀도는 20% 증가하여 300Wh/kg 이상 가능하다.

 

(2)안전성: 「원통형」의 장점은 열 폭주에 대한 가장 유력한 해결책이다. 배터리 팩 내부의 열 폭주 확산은 중요한 안전성 문제이다. 최근 발생하고 있는 배터리 사고는 모두 배터리 팩 내 특정 배터리 셀의 열폭주로 인해 발생하는데, 이로 인해 많은 양의 열이 발생하여 주변 배터리 셀이 가열되어 열폭주 확산이 발생하게 된다.

 

하지만, 원통형은 셀 용량이 작고, 단일 배터리의 열폭주로 인해 방출되는 에너지가 작아 각형 및 파우치형에 비해 확산이 발생할 가능성이 적으며, 원통의 곡면은 배터리 간의 열 전달을 어느 정도 제한한다. 즉, 원통형 배터리는 곡면으로 인해 완전히 접촉한 경우에도 여전히 큰 간격이 있어 배터리 간의 열 전달이 어느 정도 제한된다.

 

(3)고속 충전 능력: 4680 배터리는 재료 시스템의 고속 충전에 적응할 뿐만 아니라 All flag 설계를 사용하는 등 충전 속도를 높이기 위해 구조를 변경한다.

(4)높은 생산효율 → 낮은 단가

원통형은 가장 먼저 상용화된 리튬 배터리이며 생산이 가장 성숙하다. 이는 각형 및 파우치형보다 조립 효율이 높다는 사실에 반영된다. 4680의 현재 양산 효율은 알 수 없으나 원통형의 특성(동심원 권선)에 따라 생산 속도가 결정되며, 대형 원통형이 소형 원통형보다 낮더라도 각형 및 파우치형 보다 훨씬 빠르다. 1865/2170은 기본적으로 200PPM(200 배터리/분) 정도이다. 한편<200Ah 이내 각형의 경우 10-12PPM, >200Ah 이상의 큰 각형의 경우 10PPM. 파우치형의 생산 효율성은 더욱 낮다.

 

(5)대형화 → BMS 난이도 감소

테슬라의 경우, 주로 원통형 배터리 셀의 용량이 작기 때문에 특정 전력 성능을 달성하려면 총 배터리 수가 엄청나야 한다. 예를 들어 18650은 7000+ 개가 필요하고 2170은 4000+ 개가 필요하므로

배터리 시스템의 열관리 기술과의 연결 요구 사항이 매우 높다. 따라서 원통형 배터리는 많은 자동차 회사를 낙담시켰다. 하지만 4680 시대가 되면서 필요한 배터리 셀 수는 960~1360개로 줄었다

셀 수가 적다는 것은 PACK에서의 공간 활용도가 향상됨을 의미하며, 필요한 BMS도 대폭 단순화된다(여기서는 대형 원통형에 따른 방열 문제).

 

본 리포트에서 SNE는 4680에 관한 각 사의 발표자료와 분해 및 성능 test에 관한 흩어진 자료들을 체계적으로 정리하였으며, 주요 논문의 리뷰를 통해, 4680의 도입이 실제적으로 어느 정도 효과 및 성능개선이 있는지를 분석하였고, 더 나아가 외부 리서치 기관의 자료를 인용하여 독자들이 대형 원통형 시장 전망과 규모를 파악하는데 도움을 주고자 하였다.

또한, 4680 제조업체의 현황 및 주요 제품을 정리함은 물론 Gigafactory공장의 규모와 Cybertruck의 생산대수 및 생산량과의 상관 관계 등을 표시하여, 4680의 양산성에 관한 흥미 있는 정보를 제공함으로써 이 분야의 연구자 및 관심 있는 분들에게 전반적인 통찰력을 제공하고자 하였다.

 

본 보고서의 Strong Point는 다음과 같다.

① 4680에 대한 개발동향 및 정보를 집대성하여 전체적인 이해 및 파악이 용이

② 4680 셀 및 팩 분해 보고서를 상세히 분석 정리하여 이해력을 증진

③ 4680 배터리 시장 전망과 생산 전망 분석을 통해 시장규모와 성장율을 파악

④ 논문 분석을 통한 4680에 적용한 소재 및 기술의 상세 분석

 

 

 

 

 

 

 

 

 

 

 

 

목 차

 

1. 4680 원통형 배터리 개요··············································································································· 12

1.1. Tesla Battery Day 내용 분석································································································ 14

1.2. Battery Day 요약 및 Key Findings····················································································· 15

1.3. Tesla 배터리 셀 디자인········································································································· 16

1.4. Tesla 배터리 셀 공정············································································································· 18

1.4.1. 코팅 공정························································································································ 19

1.4.2. 와인딩 공정···················································································································· 20

1.4.3. 조립 공정························································································································ 20

1.4.4. 화성 공정························································································································ 20

1.5. Tesla 실리콘 음극재··············································································································· 21

1.6. Tesla Hi-Ni 양극재·················································································································· 22

1.7. Tesla 셀-차량 integration····································································································· 23

1.8. Tesla 전지 코스트 개선········································································································· 24

1.9. Tesla 4680 배터리 개발········································································································· 25

1.9.1. 개발 히스토리················································································································ 25

1.9.2. 배터리 사양(spec.)········································································································ 26

1.9.3. 배터리 적용 Tesla EV··································································································· 27

1.9.4. 배터리 공급자················································································································ 27

1.9.5. 배터리 생산 시기·········································································································· 28

1.10. 46xx 배터리 Roadmap·········································································································· 29

1.10.1. 신규 46xx 셀 디자인································································································· 29

1.10.2. 신규 46xx 셀 생산····································································································· 32

 

2. 4680 배터리 개발 동향··················································································································· 34

2.1. 비용절감 및 효율성 요구 증가·························································································· 34

2.2. 안전 요구사항 증가··············································································································· 34

2.3. 고속충전은 미래 트렌드······································································································· 38

2.4. 배터리 기업들의 시장진출 경쟁························································································ 38

2.5. Tesla 개발 동향······················································································································· 41

2.5.1. 4680 판매량, 생산 CAPA···························································································· 41

2.5.2. 4680 수요 계산·············································································································· 42

2.6. 글로벌 자동차 업체들의 layout 가속··············································································· 44

2.7. 회사별 46xx 배터리 상세 spec.························································································· 46

 

3. 4680 배터리의 상세 기술··············································································································· 54

3.1. 양극재········································································································································ 54

3.1.1. 초 하이니켈계 적용····································································································· 54

3.1.2. 생산 CAPA 구축············································································································ 56

3.1.3. 생산기술 업그레이드··································································································· 57

3.2. 음극재········································································································································ 59

3.2.1. 실리콘 기반 개발·········································································································· 59

3.2.2. 실리콘 기반 개발 타임라인······················································································· 60

3.2.3. 실리콘 음극 modification·························································································· 63

3.2.4. 실리콘 음극 산업화 가속··························································································· 68

3.3. 기타 전지 소재······················································································································· 70

3.3.1. SWCNT 도전재··············································································································· 70

3.3.2. Steel 배터리 캔·············································································································· 74

3.3.3. Al 배터리 캔··················································································································· 76

3.3.3.1. Al housing 셀 설계 컨셉············································································· 81

3.3.3.2. 46xx 대형 원통형 셀···················································································· 83

3.3.3.3. 46xx 젤리 롤 컨셉························································································· 84

3.3.3.4. 46xx 젤리 롤 열 전달 및 열 분포··························································· 84

3.3.3.5. 46xx 젤리 롤 열 시뮬레이션······································································ 85

3.3.3.6. 46xx 젤리 롤 냉각 성능 개선···································································· 86

3.4. 생산 프로세스·························································································································· 88

3.4.1. 4680 배터리 공정 기술······························································································· 88

3.4.2. 4680 생산공정 차별화································································································· 91

3.4.2.1. 건식전극 코팅································································································ 91

3.4.2.2. 건식공정 일례································································································ 94

3.4.2.3. 전극 및 탭 일체형 절단·············································································· 95

3.4.2.4. Laser 용접의 높은 난이도··········································································· 97

3.4.2.5. 일체형 Die casting과 CTC·········································································· 99

 

4. Tesla 4680 배터리 팩(pack) 분해······························································································ 103

4.1. 개요·········································································································································· 103

4.2. 배터리 분해 및 분석··········································································································· 103

4.3. Tesla 4680 배터리 셀, 팩 상세 엔지니어링 분석························································ 112

4.3.1. Tesla 4680 전지 설계 Data······················································································ 112

4.3.2. 팩 구조(셀 방향)········································································································· 122

4.3.3. 각 셀에 대한 전기연결····························································································· 123

4.3.4. 제안된 팩 조립방법··································································································· 125

4.3.5. Model 3용 팩 분석····································································································· 126

4.3.5.1. 팩 분석 결과(요약)····················································································· 126

4.3.5.2. 열 방출 상세································································································ 129

4.3.6. Model 3용 전지 전류 집전체·················································································· 131

 

5. Tesla 4680 배터리 셀 분해 및 특성························································································· 135

5.1. 요약·········································································································································· 135

5.2. 개요·········································································································································· 135

5.3. 이전 연구································································································································ 136

5.4. 상세 분석································································································································ 137

5.5. 상세 실험································································································································ 137

5.5.1. 실험 셀 개요················································································································ 137

5.5.2. 셀 분해 및 물질 추출······························································································· 138

5.5.3. 구조 및 원소 분석····································································································· 142

5.5.4. 3전극 분석···················································································································· 143

5.5.5. 전기적 특성·················································································································· 143

5.5.6. Thermal investigation································································································· 145

5.6. 결과 및 고찰························································································································· 145

5.6.1. 셀 및 Jelly roll 구조·································································································· 145

5.6.2. 전극 설계······················································································································ 147

5.6.3. 재료 특성······················································································································ 149

5.6.4. 3전극 분석···················································································································· 152

5.6.5. 용량 및 임피던스 분석····························································································· 153

5.6.6. 유사 OCV, DVA 및 ICA 분석·················································································· 154

5.6.7. HPPC 분석···················································································································· 156

5.6.8. 열적 특성 분석··········································································································· 156

5.7. 결론·········································································································································· 158

 

6. 4680 배터리 성공에 필요한 기술들·························································································· 163

6.1. Multi(all) Tab 기술················································································································ 163

6.2. Tab 용접기술·························································································································· 171

6.3. 냉각 기술································································································································ 176

 

7. 4680 배터리 에너지밀도 향상과 cost down·········································································· 183

7.1. 개요·········································································································································· 183

7.2. 에너지밀도↑/급속충전↑/코스트↓················································································· 184

7.2.1. Blade 전지/하이니켈 각형전지와 비교································································· 184

7.2.2. 고속충전 속도 향상··································································································· 186

7.2.3. 건식전극(DBE)을 통한 생산 촉진 및 코스트 다운··········································· 188

7.3. 고농도 전해질 적용············································································································· 191

7.3.1. GWh당 4680 전해질양 감소··················································································· 191

7.3.2. 고농도 전해질과 LiFSI 첨가···················································································· 195

7.3.3. 불소계 FEC 첨가········································································································· 200

7.4. 4680 전해액 주요 기업······································································································ 202

 

8. 4680 배터리 열 문제 예측 및 완화 방법················································································ 204

8.1. 실험 요약································································································································ 204

8.2. 실험 방법································································································································ 204

8.3. 열전달 모델 방정식············································································································· 206

8.4. 실험 결과 및 토의··············································································································· 207

8.5. 실험 결론································································································································ 210

 

9. 원통형 LIB 셀의 설계, 특성 및 제조························································································ 212

9.1. 개요·········································································································································· 212

9.2. 실험재료 및 방법················································································································· 214

9.2.1. 셀 디자인······················································································································ 214

9.2.2. 셀 속성·························································································································· 217

9.2.3. 셀 에너지밀도·············································································································· 217

9.2.4. 셀 임피던스·················································································································· 218

9.2.5. 셀 온도·························································································································· 218

9.3. 실험결과 및 고찰················································································································· 219

9.3.1. 원통형 LIB셀 디자인·································································································· 219

9.3.2. 젤리 롤 디자인··········································································································· 221

9.3.2.1. 기하학(Geometry)······················································································· 221

9.3.3. 탭 디자인······················································································································ 223

9 .3.4. 셀 속성························································································································· 227

9.3.4.1. 셀 에너지밀도······························································································ 227

9.3.4.2. 셀 저항··········································································································· 228

9.3.4.3. 셀 열적 거동································································································ 229

9.3.5. 젤리 롤 제조················································································································ 231

9.4. 실험 결론································································································································ 234

 

10. Tabless 원통형 LIB 셀의 셀 size 및 housing 재질의 영향············································ 235

10.1. 전체적인 개요····················································································································· 235

10.2. 실험········································································································································ 236

10.2.1. Reference cell············································································································· 236

10.2.2. 셀 모델링···················································································································· 237

10.2.2.1. 셀 치수 및 기하학적 모델····································································· 237

10.2.2.2. 젤리 롤 전극층·························································································· 237

10.2.2.3. 중공 코어(Hollow core)··········································································· 237

10.2.2.4. Tabless design···························································································· 237

10.2.3. 셀 housing················································································································· 238

10.2.4. 열-전기-전기화학 framework················································································ 238

10.2.4.1. Boundary conditions과 discretization················································· 239

10.3. 실험결과 및 논의··············································································································· 239

10.3.1. 에너지밀도·················································································································· 239

10.3.1.1. 셀 직경의 영향·························································································· 239

10.3.1.2. 셀 높이의 영향·························································································· 241

10.3.1.3. Housing 재료의 영향··············································································· 241

10.3.2. 급속 충전 성능········································································································· 242

10.3.2.1. 열전달 계수 제어 알고리즘 구현························································ 242

10.3.2.2. 축냉각에 따른 셀 높이 및 housing 재료의 영향··························· 243

10.3.2.3. 축냉각에 따른 셀 직경 및 housing 재료의 영향··························· 246

10.3.2.4. 탭 디자인의 영향과 직렬 저항의 스케일링······································ 250

 

10.3.2.5. 급속충전성능에 대한 셀 크기 및 housing 재료의 영향·············· 252

10.4. 실험 결론····························································································································· 253

 

11. 4680 셀 업체 및 자동차 OEM들의 현황·············································································· 256

11.1. Tesla········································································································································ 256

11.2. Panasonic······························································································································ 258

11.3. LGES········································································································································ 260

11.4. SDI·········································································································································· 261

11.5. EVE·········································································································································· 261

11.6. BAK········································································································································· 266

11.7. CATL······································································································································· 266

11.8. Guoxuan Hi-TECH··············································································································· 268

11.9. SVOLT····································································································································· 269

11.10. CALB····································································································································· 270

11.11. Envision AESC···················································································································· 271

11.12. LISHEN································································································································· 273

11.13. Easpring······························································································································ 274

11.14. 금양····································································································································· 275

11.15. BMW···································································································································· 276

11.16. Rimac··································································································································· 280

 

12. Tesla 4680 battery 특허분석···································································································· 281

12.1. Tabless 전극을 구비한 전지(PTC/US2019/059691)··················································· 281

12.2. Tabless 에너지저장 디바이스들 및 그 제조 방법들(PTC/US2021/050992)······· 285

12.3. 건식공정 특허1(미립자 비섬유화 바인더 함유: US11545666 B2)························ 294

12.4. 건식공정 특허2(건식전극용 접착 부동태막 조성물: US11545667 B2)··············· 298

 

13. 4680 배터리 시장 전망··············································································································· 301

13.1. Overall 시장 전망··············································································································· 301

13.2. 4680 주요 소재 시장 전망······························································································ 306

13.2.1. 실리콘 기반 음극재······························································································· 306

13.2.2. Hi-Ni 삼원계 양극재······························································································ 310

13.2.3. LiFSI 리튬염·············································································································· 312

13.2.4. 복합 동박·················································································································· 314

13.2.5. PVDF 바인더············································································································ 316

13.2.6. CNT 도전재·············································································································· 316

13.2.7. Laser welding 장비································································································· 317

13.2.8. Housing CAN··········································································································· 318

13.2.9. Ni 도금 CAN············································································································ 319

13.3. 4680 수요 전망 및 CAPA 전망······················································································ 321

 

14. Tesla 4680 cell 생산 전망·········································································································· 325

14.1. 각 컨설팅 기관별 4680 전망치····················································································· 325

14.2. Tesla/BMW 4680 수요 전망치························································································ 325

14.3. Cybertruck용 Tesla 4680 셀 생산 전망······································································· 326

14.3.1. 4680 Giga Texas 생산 추정치············································································· 326

14.3.2. 4680 cell 생산 CAPA vs. Cybertruck 생산 대수············································ 327

14.3.3. 4680 cell 연간 CAPA vs. Daily 생산량······························································ 328

14.3.4. 4680 cell 생산 CAPA vs. 생산 시간 추이························································ 328

14.3.5. Tesla Giga Factory P/P line 주요 공정 모음···················································· 329