前言

人類正加速進入人工智能與清潔能源時代。電子產品將在這個時代扮演關鍵角色。雖然半導體工藝的進步使得元器件的能效比不斷提高，但人們對產品功能提升的需求還是超越了元器件工藝技術的進步速度，這表現為幾乎所有的電子產品的體積功率密度都在逐年升高，也直接導致了原來越嚴重的熱管理問題。

熱設計工程師一職在這樣的背景下應運而生。這是一個相對新型的職位，截至2020年，我國還沒有一所高校設立此專業。在從事實際熱設計工作的過程中，我遇到過很多無法獲取答案甚至連參考資料都很少的問題。鑒于此，我將我個人的學習和思考總結下來，寫就了本書。大體上，這本書系統性地回答了以下問題：

l  為什么電子產品要控制溫度？

l  溫度控制的基本理論依據是什么？

l  芯片、單板等內部組成如此復雜，我們如何從熱設計的角度理解它們？

l  溫度控制常用的手段有哪些？

l  散熱器、導熱界面材料、風扇、液冷板、熱管、均溫板等為什么會成為當前模塊化的熱管理部件？如何通過這些模塊的設計選型控制產品的溫度？

l  熱設計工程師如何在控制好產品溫度的前提下，同步控制好產品噪音？

l  如何對產品進行熱測試驗證工作？這些設備的工作原理是怎樣的？就驗證結果精度而言，各自有什么優缺點？

l  如何使用熱仿真軟件加速設計進程，甚至實現智能化乃至自動化設計？

l  從理論基礎層面，怎么理解熱管理方案的智能化及熱-力-電-磁的耦合趨勢？

l  作為一個相對新興的職能，如何融入到產品當前成熟的開發流程中去？

這本書最大的特點是所有的闡述都試圖從工程實際出發，在通俗易懂和嚴謹深入層面，我選擇了前者，所以這本書里僅保留了幾個最基礎、形式最簡單的公式。我的目的是讓基礎薄弱的讀者也能讀懂，讓沒有工程經驗的讀者能夠快速理解我所想表達的熱設計思維，并在實踐中設計出溫度表現優良的產品。

作者水平有限，書稿雖幾經審改，但其中錯誤與不足之處必不少見，懇請讀者不吝賜教。

陳繼良Leon Chen

2020-4-13

附書籍目錄

目 錄

前言·························································································································V
目 錄·························································································································I

第一章 電子產品熱設計的意義 ·······················································································1
1 溫度對電子產品的影響···················································································1
2 溫度對芯片的影響機理···················································································2
2.1 熱應力和熱應變····················································································2
2.2 器件炸裂·····························································································4
2.3 腐蝕···································································································4
2.4 氧化物分解··························································································4
2.5 芯片功耗·····························································································4
2.5 電氣性能變化·······················································································6
3 解決芯片熱可靠性的兩個維度··········································································6
4 熱設計方案的評估標準···················································································6
5 本章小結 ·····································································································7
參考文獻 ········································································································8

第二章 熱設計理論基礎 ································································································9
1 熱和溫度 ·····································································································9
1.1 熱動說和熱質說····················································································9
1.2 溫度的物理意義··················································································10
2 傳熱學 ······································································································11
2.1 熱傳導（Thermal Conduction） ·······························································12
2.2 熱對流（Thermal Convection） ·······························································15
2.3 熱輻射（Thermal Radiation） ·································································16
3 熱力學 ······································································································18
3.1 熱力學第一定律··················································································19
3.2 熱力學第二定律··················································································19
3.3 熱力學第三定律··················································································20
3.4 熱力學第零定律··················································································20
3.5 理想氣體定律·····················································································20
4 流體力學 ···································································································22
4.1 流體的重要性質——粘性······································································22
4.2 流體壓強——靜壓，動壓和總壓 ····························································23
4.3 表壓、真空度和絕對壓強······································································25
4.4 流體流動狀態——層流和湍流································································25
附加閱讀：導熱系數的本質··············································································27
5 本章小結 ···································································································28
參考文獻 ······································································································29

第三章 熱設計研發流程 ······························································································30
1 需求分析(Requirement Analysis) ······································································30
2 概念設計(Concept Design)··············································································32
3 詳細設計(Detail Design) ················································································33
4 測試驗證(Test and Verification) ·······································································33
5 回歸分析(Regression Analysis) ········································································34
6 發布與維護(Launch and Maintenance) ·······························································34
7 本章小結 ···································································································34
參考文獻 ······································································································35

第四章 散熱方式的選擇 ······························································································36
1 散熱方式選擇的困難性·················································································36
2 自然散熱 ···································································································38
3 強迫風冷 ···································································································39
4 間接液冷 ···································································································40
5 直接液冷 ···································································································41
6 本章小結 ···································································································41
參考文獻 ······································································································42

第五章 芯片封裝和電路板的熱特性 ···············································································43
1 IC 芯片封裝概述 ··························································································43
2 芯片封裝熱特性 ··························································································44
2.1 芯片熱特性基礎··················································································44
2.2 熱阻的概念························································································45
2.3 芯片熱特性的熱阻描述·········································································46
3 芯片封裝熱阻的影響因素··············································································49
3.1 封裝尺寸···························································································49
3.2 封裝材料···························································································49
3.3 熱源尺寸···························································································50
3.4 單板尺寸和導熱系數············································································50
3.5 芯片發熱量以及外圍氣流速度································································51
4 實驗測量時結溫的反推計算公式·····································································51
5 常見的芯片封裝及其熱特性···········································································52
5.1 BGA—Ball Grid Array Package 球柵陣列式封裝··········································53
5.2 TO——Transistor Outline Package 晶體管外形封裝·······································54
5.3 QFP---- Quad Flat Pack 四邊扁平封裝 ·······················································54
5.4 QFN/DFN ---- (Quad/Dual Flat No-Lead)四邊/雙邊無引腳扁平封裝···················55
5.5 封裝演變趨勢和熱設計面臨的機遇與挑戰 ················································56
6 印制電路板熱特性及其在熱設計中的關鍵作用···················································57
6.1 PCB 熱傳導特點 ··················································································57
6.2 PCB 銅層鋪設準則——熱設計角度··························································58
6.3 熱過孔及其設計注意點·········································································59
7 本章小結 ···································································································61

參考文獻 ······································································································62

第六章 散熱器的設計 ·································································································64
1 散熱器設計需考慮的方面··············································································64
1.1 發熱源熱流密度··················································································64
1.2 元器件溫度要求和工作環境···································································66
1.3 產品內部空間尺寸···············································································66
1.4 散熱器安裝緊固力···············································································67
1.5 成本考量···························································································67
1.6 外觀設計···························································································68
2 幾種常見的散熱器優化設計思路·····································································68
2.1 熱傳導——優化散熱器擴散熱阻 ····························································68
2.2 對流換熱——強化對流換熱效率 ····························································69
2.3 輻射換熱——選擇合適的表面處理方式 ···················································70
2.4 總結·································································································71
3 散熱器設計注意點匯總·················································································72
4 散熱器的生產工藝························································································72
5 本章小結 ···································································································72
參考文獻 ······································································································74

第七章 導熱界面材料的選型設計 ··················································································75
1 為什么需要導熱界面材料··············································································75
2 導熱界面材料定義及種類··············································································75
2.1 導熱界面材料定義···············································································75
2.2 導熱界面材料的種類············································································76
3 導熱界面材料的選用關注點···········································································81
3.1 材料自身屬性·····················································································81
3.2 應用場景因素·····················································································84
4 導熱界面材料的實例運用··············································································85
4.1 導熱硅脂的實際運用············································································85
4.2 導熱襯墊的實際運用············································································86
4.3 導熱填縫劑的實際運用·········································································87
4.4 石墨片的實際運用···············································································87
5 導熱界面材料選用的復雜性···········································································88
6 本章小結 ···································································································88
參考文獻 ······································································································90

第八章 風扇的選型設計 ······························································································91
1 幾何尺寸 ···································································································91
2 確定風量 ···································································································92
3 確定風扇風壓·····························································································93
4 平行翅片散熱器流阻計算··············································································94
5 風扇的抽風和吹風設計·················································································97
5.1 抽風設計···························································································98
5.2 吹風設計···························································································98
6 風扇轉速控制方式·······················································································98
7 風扇噪音考量·····························································································99
8 風扇相似定理····························································································100
9 風扇壽命可靠性 ·························································································100
10 風扇失速區 ·····························································································102
11 風扇選型方法匯總 ····················································································103
12 散熱器和風扇的綜合設計 ···········································································104
13 本章小結 ································································································106
參考文獻 ·····································································································107

第九章 熱管和均溫板 ································································································108
1 熱管和均溫板的特點和典型應用····································································108
2 熱管和 VC 的基本工作原理 ··········································································110
3 熱管或 VC 的性能指標 ················································································111
4 超薄熱管和超薄 VC ····················································································113
5 熱管和 VC 產品要考慮的細觀因素··································································115
6 本章小結 ··································································································115
參考文獻 ·····································································································116

第十章 熱電冷卻器、換熱器和機柜空調 ········································································117
1 熱電制冷原理····························································································117
2 熱電制冷器在電子散熱中的優缺點·································································117
3 熱電制冷器的選型步驟················································································119
3.1 確定工作電流····················································································120
3.2 確定工作電壓····················································································120
3.3 確定 COP 值和選擇高效 TEC 的迭代方式 ················································120
3.4 TEC 與系統的匹配 ··············································································121
4 換熱器工作原理 ·························································································122
5 換熱器的選型····························································································123
5.1 確定需求··························································································123
5.2 計算換熱效率····················································································123
6 機柜空調 ··································································································125
7 本章小結 ··································································································127
參考文獻 ·····································································································128

第十一章 液冷設計 ···································································································129
1 液冷設計概述····························································································129
1.1 直接液冷··························································································129
1.2 間接液冷··························································································130
2 液冷散熱的特點 ·························································································130
3 液冷系統的分類與組成················································································131
3.1 封閉式單循環系統··············································································131
3.2 封閉式雙循環系統··············································································132
3.3 開放式系統·······················································································132
3.4. 半開放式系統···················································································132
4 液冷設計各部分注意點················································································133
4.1 液體工質選擇····················································································133
4.2 冷板的設計·······················································································135
4.3 冷管和接頭·······················································································136
4.4 泵的選擇··························································································137
4.5 冷排/換熱器的選型設計·······································································140
4.6 其它附件··························································································141
5 冷板散熱器的設計步驟和常見加工工藝···························································142
5.1 計算流量··························································································143
5.2 確定冷板材質····················································································143
5.3 流道設計··························································································144
5.4 冷板類型及其優缺點···········································································145
6 本章小結 ··································································································147
參考文獻 ·····································································································148

第十二章 熱設計中的噪音 ··························································································149
1 熱設計與噪音的關系···················································································149
2 聲音基礎知識概述······················································································149
2.1 聲音的本質·······················································································149
2.2 噪聲產生原因····················································································149
2.3 聲音的幾個關鍵參數···········································································150
3 聲音的分析 ·······························································································153
3.1 頻程與頻譜·······················································································153
3.2 響度與響度級····················································································154
3.3 計權聲級··························································································155
4 聲音的傳播 ·······························································································156
5 電子產品熱設計中的噪音·············································································157
5.1 氣動噪聲··························································································157
5.2 機械噪聲··························································································158
5.3 電磁噪聲··························································································158
6 噪音測量 ··································································································158
7 噪音控制設計····························································································159
7.1 控制聲源··························································································159
7.2 控制傳聲路徑····················································································159
7.3 控制聲音接受者·················································································160
8 噪聲仿真 ··································································································161
9 本章小結 ··································································································161
參考文獻 ·····································································································162

第十三章 風扇調速策略的制定和驗證 ···········································································163
1 為什么要對風扇進行調速·············································································163
2 風扇智能調速的條件···················································································163
2.1 風扇轉速必須可控··············································································164
2.2 必須有可實時反饋產品散熱風險的傳感器 ···············································164
2.3 系統中必須內置有效的風扇調速程序 ·····················································165
3 風扇調速策略的設計···················································································167
3.1 溫度傳感器的布置··············································································167
3.2 風扇調速策略整定步驟········································································167
4 異常情況的風扇轉速應對·············································································172
5 本章小結 ··································································································172

第十四章 熱測試·······································································································173
1 熱測試的目的和內容···················································································173
2 熱測試注意事項 ·························································································173
2.1 確保設備的配置和負載與測試工況對應 ··················································173
2.2 確保設備使用的散熱物料與設計方案一致 ···············································173
2.3 根據散熱方式選擇合適的測試環境 ························································174
2.4 關注測試讀取結果數據的穩定性 ···························································174
3 溫度測試 ··································································································174
3.1 熱測試設備·······················································································174
3.2 接觸式測溫·······················································································175
3.3 非接觸式測溫····················································································176
4 熱測試常用設備儀器···················································································180
5 撰寫熱測試報告 ·························································································182
6 本章小結 ··································································································184
參考文獻 ·····································································································185

第十五章 熱仿真軟件的功能，原理和使用方法 ·······························································186
1 熱仿真的作用····························································································186
2 熱仿真的基本原理······················································································186
3 熱仿真軟件的選擇······················································································189
4 熱仿真軟件的合理使用················································································191
4.1 信息收集··························································································191
4.2 幾何建模和屬性賦值···········································································192
4.3 網格劃分··························································································193
4.4 模型設置··························································································194
4.5 求解計算和后處理··············································································195
5 本章小結 ··································································································196

第十六章 常見電子產品熱設計實例 ··············································································197
1 自然散熱產品····························································································197
1.1 超薄平板電腦····················································································198
1.2 智能手機··························································································200
1.3 戶外通訊設備····················································································204
1.4 LED 燈···························································································207
1.5 盒式自然散熱終端··············································································210
2 強迫風冷設計····························································································213
2.1 筆記本電腦·······················································································214
2.2 服務器·····························································································217
3 液冷和風冷的混合冷卻················································································222
4 動力電池熱管理 ·························································································224
4.1 電池熱管理系統的目標········································································226
4.2 電池熱學信息確定··············································································226
4.3 電池組熱管理方案類型········································································229
4.4 動力電池加熱系統··············································································232
4.5 動力電池熱管理系統的重量考慮 ···························································234
5 本章小結 ··································································································234
參考文獻 ·····································································································235

第十七章 熱、電、磁的結合 ·······················································································236
1 一些電磁學概念 ·························································································237
1.1 電容································································································237
1.2 介電常數··························································································238
1.3 介電損耗··························································································239
1.4 磁導率·····························································································240
1.5 磁化機理··························································································242
1.6 磁滯損耗··························································································245
2 信號傳輸 ··································································································246
2.1 無線電磁波的形成··············································································246
2.2 無線電波的傳輸·················································································248
3 電磁兼容、電磁屏蔽以及對熱設計的影響························································251
3.1 電場屏蔽··························································································251
3.2 磁場屏蔽··························································································252
3.3 電磁屏蔽··························································································254
3.4 電磁兼容··························································································255
4 本章小結 ··································································································256
參考文獻 ·····································································································257

后記 ·······················································································································259
致謝 ·······················································································································260
作者簡介 ·················································································································261 

從零開始學散熱-目錄-前言-后記-20200826.pdf