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三元鋰電池還是磷酸鐵鋰電池 動力電池到底應該用哪種4
SEGL ENERGY CO., LTD. No.76, Wuxun St., Anle Dist., Keelung City 204, Taiwan
GM’s Electric Dream in China Suddenly Looks Underpowered The launch of a new Buick electric vehicle has been put on hold until a new battery supplier can be identifiedA Buick Velite 6 displayed at the Beijing auto show in April. PHOTO: WANG ZHAO/AGENCE FRANCE-PRESSE/GETTY IMAGES By  Trefor Moss Updated Aug. 29, 2018 10:22 a.m. ET SHANGHAI— General Motors Co.’s GM -0.85% plans to ramp up electric-vehicle production in China were set back after the auto maker determined the Chinese-made batteries it intended to use failed to meet its own performance and safety standards during testing. GM was set to enter production next month on its plug-in hybrid Buick Velite 6, a local variant of the Volt, with a pure-electric version due to follow early next year. That launch schedule has now been postponed, with internal tests showing the battery, supplied by A123 Systems, didn’t meet GM’s quality standards, according to a person familiar with the situation. EV batteries are complex components that can’t easily be switched, spelling lengthy delays in getting the Velite 6 into production. A GM spokeswoman declined to comment on the situation, but said the company still intends to launch 10 EVs in China by 2020. However, that target was announced over a year ago, long before the battery supply problem arose. “GM’s plan is to deliver 20 EVs globally by 2023,” the spokeswoman said. “In China, we are on track to introduce 10 new energy vehicles between 2016 and 2020. Given those two goals, all-electric vehicles like the Velite 6 battery electric vehicle are obviously our priority.” A123 Systems didn’t respond to a request seeking comment. The Livonia, Mich.-based company was bought out of bankruptcy by Chinese auto-parts giant Wanxiang Group Corp. in 2013, and it operates a battery plant in the eastern city of Hangzhou to supply the China market. Auto makers operating in China are scrambling to fulfill a Chinese government order requiring them to start building electric vehicles next year. Without a battery, GM is one of those in danger of missing Beijing’s target. China’s timetable is “difficult to achieve” for longtime manufacturers of gasoline cars being forced to make the rapid switch to electric, said Jing Yang, an associate director at Fitch Ratings. “The situation is different company by company,” she said, with some players well set to meet the target, and others floundering. Though seen as an EV market leader in the U.S., where it sells the Chevrolet Bolt and Volt electric cars, GM has had difficulty translating that advantage into success in China, the world’s biggest EV market. GM originally planned to use batteries from South Korea’s LG Chem Ltd. But in 2016, China mandated that auto makers use batteries from a list of approved suppliers, all of which are Chinese. China-owned Volvo Car Group, however, is an exception: It is allowed to use batteries using LG Chem-licensed technology in its locally built cars. Auto makers cite the exclusion of foreign batteries as an example of Chinese government protectionism that handicaps both foreign battery firms and the auto makers they supply, while handing advantages to local rivals. Those complaints are among the factors fueling the U.S. trade actions against China. China’s Ministry of Industry and Information Technology didn’t respond to a request for comment. The Chinese are on course to buy more than 1 million electric vehicles this year—nearly all of them built by local auto makers. Riding the boom are fast-growing Chinese battery suppliers such as BYD Co. and Contemporary Amperex Technology Co. , now among the world’s biggest lithium-ion battery companies. In its rush to develop battery technology, China risks shortcomings in quality and safety performance, said Thomas Barrera, president of LIB-X Consulting, a battery consultancy based in Long Beach, Calif. “There are concerns with the quality of Chinese-manufactured cells and batteries,” he said. “Chinese cells are very attractive because they’re inexpensive, but people may not realize that these cells may not have gone through the necessary qualification testing before going to market.” China’s EV policies have created a dilemma for foreign auto makers: They are obliged to build electric vehicles and use Chinese batteries, but they can’t compromise their global standards and use components in which they lack confidence—especially batteries, which have a history of catching fire. While most foreign auto makers have publicly expressed confidence in their ability to meet the EV quota, few have explained in detail how they will achieve a target requiring electric vehicles to make up roughly 3%-4% of their 2019 output. Some are making tangible progress. On Monday, Nissan Motor Co. started production of its first made-for-China electric car, while Volkswagen AG unveiled its first pure-electric car for China in April. Ford Motor Co. —which began developing electric vehicles later than rivals such as GM—has one plug-in hybrid model on the market in China, and plans to launch its first pure-electric car by the end of 2019. GM launched its first Chinese pure-electric car, the Baojun E100, last year. It has sold more than 22,000 units of the budget EV—which starts at about $6,900—despite only making it available in a handful of locations so far. However, GM, which builds roughly 4 million cars in China a year, would need to build about 100,000 E100s next year to meet the quota, assuming other models fail to come onstream. There is a backstop for auto makers that miss the 2019 target: The regulations allow them to transfer EV credits earned in 2020, and use them to make up any 2019 shortfall. If they are still noncompliant, auto makers will then be forced to buy EV credits from rivals through a credit-trading system, which the authorities have yet to articulate in detail. Auto makers bringing electric vehicles to market early can benefit from generous subsidies, but those are due to end in 2020. “Traditional auto makers will no doubt struggle to remix their portfolio to EVs,” said Bill Russo, the founder of Automobility, a Shanghai consultancy. And without subsidies, the struggle to build enough electric vehicles will soon become a battle to make the costly machines profitable, he said. https://www.seglenergy.com.tw/en/hot_287405.html GM’s Electric Dream in China Suddenly Looks Underpowered The launch of a new Buick electric vehicle has been put on hold until a new battery supplier can be identified 456f5da2b493c45c47107207e011f004.jpg A Buick Velite 6 displayed at the Beijing auto s 2021-03-10 2022-03-10
SEGL ENERGY CO., LTD. No.76, Wuxun St., Anle Dist., Keelung City 204, Taiwan https://www.seglenergy.com.tw/en/hot_287405.html
SEGL ENERGY CO., LTD. No.76, Wuxun St., Anle Dist., Keelung City 204, Taiwan https://www.seglenergy.com.tw/en/hot_287405.html
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儘管國內對新能源汽車的補貼政策已經開始退坡,但逐漸豐富的基礎設施和愈發豐富的可選車型也讓消費者們開始接受新能源汽車的普及。除了作為限購地區無法購買燃油汽車的替代解決方案之外,新能源汽車也有許多得天獨厚的優勢。安靜的駕駛環境、清潔的能源類型和低廉的用車成本,甚至包括起步時瞬間輸出的超大扭矩,都能讓身邊不少開燃油汽車的朋友羨慕不已。

 

而作為電動汽車動力之源的電池,自然是最為重要的零部件之一。電動汽車的續航、充放電等一切使用也都與電池的性能有著千絲萬縷的聯繫。目前國內的動力電池主要分為兩個派系,根據正極材料的不同分為磷酸鐵鋰派和三元材料派。雖然兩者均屬於二次電池,都可以反覆進行充放電使用,但由於材料的差異,在最終反映到使用層面的性能還是有比較大的差別。

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三元鋰電池還是磷酸鐵鋰電池?

要想搞清楚究竟哪種電池更好,我們應該先對這兩者的區別有一個簡單的了解。

所謂磷酸鐵鋰電池,就是指用磷酸鐵鋰作為正極材料的鋰離子電池。這一類電池的特點是不含貴重金屬元素(比如鈷等)。由於不含有貴重金屬材料,磷酸鐵鋰電池的原材料成本就可以被壓縮的非常低廉。在實際使用中,磷酸鐵鋰電池具有耐高溫,安全穩定性強,價格便宜,循環性能更好的優勢。

而三元鋰電池是指使用鎳鈷錳酸鋰做為正極材料,石墨作為負極材料的鋰電池。與磷酸鐵鋰不同,三元鋰電池電壓平台很高,這也就意味著在相同的體積或是重量下,三元鋰電池的比能量、比功率更大。除此之外,在大倍率充電、和耐低溫性能等方面,三元鋰電池也有很大的優勢。

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筆者一直認為,技術並沒有好壞或是優劣之分,只是適用於不同的產品或是環境。單論電池,也沒有所謂的誰更好誰更差。只是套用到實際使用場景中,三元鋰電池相比磷酸鐵鋰電池,更加適應現在以及未來的家用電動汽車。

 

為什麼三元鋰電池更適合家用電動汽車?

一、低溫放電性能更好
我國幅員遼闊,氣候覆雜,從最北端的東北三省到最南端的海南諸島溫度變化非常豐富。以北京為例,作為電動汽車的主力市場,北京夏季最高溫度在40℃左右,而冬季則基本保持在零下16℃左右,甚至更低。這樣的溫度區間顯然適合低溫性能更佳的三元鋰電池。而注重耐高溫性能的磷酸鐵鋰電池在北京的冬季會顯得有些乏力。
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「相對25℃容量」是指不同溫度條件下放電容量與25℃時放電容量的比值。該數值能夠準確反映出電池在不同溫度條件下續航的衰減,越接近100%,電池表現越好。

從上圖中能夠看出,以25℃為基準常溫,兩類電池在55℃高溫下放電與常溫25℃下放電,放電容量幾乎沒有差別。但在零下20℃時,三元鋰電池與磷酸鐵鋰電池相比有比較明顯的優勢。

二、能量密度更高

根據國內三元材料18650圓柱電池龍頭企業——比克電池提供的資料,其18650電池的能量密度已經達到了232Wh/kg,後續將會進一步提高至293Wh/kg。而相比之下,目前國內主流的磷酸鐵鋰電池能量密度也僅達到150Wh/kg左右,據國內電池行業專家剖析,未來幾年之內,磷酸鐵鋰電池的能量密度能夠達到300Wh/kg的希望非常渺茫。
不同於體積龐大的電動巴士,對於家用電動汽車來說,空間永遠是第一位的。能量密度較低的磷酸鐵鋰電池將會占據原本就不多的汽車空間,並且由於更重的質量,在使用時的放電續航也會受到比較大的影響。相對而言能量密度較高的三元鋰電池在解決重量問題的同時也為家庭用車節省出了空間。

三、充電效率更高

除了續航之外,充電也是電動汽車在實際使用中的重要環節,而三元鋰電池在充電效率方面較磷酸鐵鋰電池有著非常大的優勢。

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目前市面上較為常見的充電方式為恆流恆壓式充電。一般在充電開始時先採用恆流充電,此時的電流較大,充電效率相對更高。而在電壓達到一定數值之後,降低電流改為恆壓充電,這樣可以讓電池充的比較滿一些。在這個過程中,恆流充電容量與電池總容量的比值,稱為恆流比。它是衡量一組電池在充電過程中充電效率的關鍵數值。通常百分比越大說明在恆流階段充入的電量越高,也就證明該電池的充電效率更高。

 

從表中可以看出,三元鋰電池與磷酸鐵鋰電池在10C以下充電時,恆流比無明顯差距,10C以上倍率充電時,磷酸鐵鋰電池恆流比例迅速降低,充電效率迅速降低。

四、循環壽命可以放心
對於家庭用車來說,三元材料和磷酸鐵鋰動力電池的額定循環壽命都遠遠超過了實際用戶的使用習慣,因此在使用壽命上可以完全放心。以比克電池目前的高容量18650電池為例,在充放電循環1000次之後,電池容量依然能夠保持在最初的90%以上。由於筆者本身也是電動汽車車主,全年僅有冬季最冷的1個多月,頻繁開暖風的時候才能達到2天一充電,其餘時間基本3-4天一充。假設全年平均3天一充電來計算,使用1年需要充大約6次電,循環壽命1000次使用完畢大約需要8年時間,這也基本超過了目前我國消費者平均的換車周期。
五、足夠安全的材料和工藝

傳統內燃機汽車中危害最大的部分是蘊含巨大能量的燃料,像汽油這樣燃點低易爆炸的液態燃料一旦泄露就非常容易造成極大的安全隱患。而新能源汽車的動力電池,經過完善的電池管理系統(BMS)監控,每一顆電池都能得到最準確的控制,預防事故的產生。

以比克18650電池產品為例。在單體電芯工藝上,比克選擇在正負極分別配置保護添加劑和反應性添加劑,阻止電解液分解導致的安全問題。同時添加陶瓷隔膜和負極陶瓷塗層等安全防護手段,從根源控制事故的產生。此外,比克小型圓柱18650電池成組模式,每顆電池之間都保持足夠的安全距離,確保單顆電池的事故不會對其他電池造成影響。

三元鋰電池正在主導未來的動力電池市場

在電動汽車領域,美國的特斯拉一直是國內諸多車企的標杆。而談到傳統車企研發新能源汽車的實力,寶馬i3的推出也成為了教科書般的典範。有趣的是,這兩款車都選擇了三元鋰電池作為動力電池。反觀國內市場,像江淮、比亞迪、北汽等不少汽車廠商也開始將旗下原本使用磷酸鐵鋰電池的車型換裝三元鋰電池。

還是那句話:技術不分好壞,只有適合或者不適合。國內外車企對於電池類型選擇的「不謀而合」也絕對不是巧合。相信在不久的將來,電動汽車的電池市場將會重新洗牌,三元鋰電池憑藉其耐低溫、高能量密度、高充電效率、不錯的循環壽命以及更強的安全性等特性,也會在新的市場中站穩腳跟

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