粉末電阻測試概述Overview of Powder Testing

材料電阻直接影響著全電池功率表現(xiàn)。通過測量分析粉末、極片電阻等特性，在快速預(yù)測電池性能方面具有重要意義。 Resistivity of material directly affects the power performance of full battery. It is very important to predict the battery performance quickly by measuring and analyzing the characteristics of powder and electrode resistivity . 粉末導電材料的電阻率與材料本體電阻特性、粒度直接相關(guān)外，還與粉體堆積松緊度等直接關(guān)聯(lián)。The resistivity of powder is not only directly related to the resistance characteristics and particle size of conductive material itself, but also directly related to the tightness of powder accumulation.

當前測量瓶頸Current situation and difficulties

粉末電阻的測試有多種方法，其中四探針是常用的方法之一。不過，四探針法仍存在如下問題亟需解決，以便方便高效地進行粉體電阻及壓實密度的測試。Four probes is one of the commonly used methods for powder resistivity. However, the following problems need to be solved in order to facilitate and efficiently test powder resistance and press density.

非原位（需預(yù)壓片，再轉(zhuǎn)移至設(shè)備上測試），測試過程繁雜，影響因素眾多；Ex-situ test(requires prepressing, then transferring it to the equipment for testing). The testing process is complicated and there are many influencing factors.

沒有粉末電阻與壓實密度一體設(shè)備；No powder resistivity and press density integrated equipment;

無法實現(xiàn)不同壓力下粉末電阻與壓實密度同步測試； The synchronous test of powder resistivity and press density under different pressures cannot be realized;

無法實現(xiàn)大壓力下粉末電阻與壓實密度測試 ；The test of powder resistivity and press density under high pressures cannot be realized.

測試原理介紹Principle

測試系統(tǒng)基于四探針&兩探針測試原理，通過集約化集成高精度模架、位移、電壓、電流、壓力、溫濕度等核心零部件與傳感器，實現(xiàn)粉體電阻與壓實特性精準檢測。

Through intensive integration of high-precision die frame, displacement, voltage, current, pressure, temperature and humidity and other core components and sensors, the test system based on the principle of four-probe & two-probe testing can accurately test powder resistivity and press density.

測量模式介紹Test Mode

測試系統(tǒng)實現(xiàn)以下功能 (類似電池充放電，CC+CV模式，Step Charge 模式)； Test system realize the following function（similar to cell test, CC+CV mode，Step Charge mode）：

不同加載壓力速率到目標壓力，目標壓力保持一定時間， 直到電阻變化率小于0.01mΩ/s，完成測試；

For example ：0.1t/s Constant Force rate(CFR) to 0.3t, Constant Force(CF) to 0.01mΩ/s, Frequency 0.2S。

系統(tǒng)參數(shù)Specifications

產(chǎn)品特色與優(yōu)勢Features and Advantages

可靠性分析Reliability Analysis

測試系統(tǒng)采用的是可控壓力加壓的測試來保證接觸一致性，從而確保了測量的可靠性及穩(wěn)定性，設(shè)備測試結(jié)果可靠，并且能達到量具R&R的標準要求。Test system adopt the controllable pressurize test to guarantee the contact uniformity, reliability and stability of test.

R&R可區(qū)分的類別數(shù)為9.35；The number of distinguishable R & R categories is 9.35;

方差分量貢獻率及研究變異值大小同樣顯示系統(tǒng)的可靠性良好；%SV and 6*SD also display the better system reliability;

應(yīng)用領(lǐng)域與方向Application Fields

ACCFILM膜片電阻測試系統(tǒng)應(yīng)用于鋰電池、超級電容器及鎳氫電池等二次電池材料研發(fā)與生產(chǎn)相關(guān)領(lǐng)域的生產(chǎn)制造企業(yè)、大學及科研院所，其主要輸出測量測試如下：

Manufacturing enterprises, universities and research institutes of lithium battery, supercapacitor and other secondary battery material related fields;

石墨混合壓實密度分析Mixed Graphite Density Analyse

不同LFP材料測試分析Different LFP Material Analysis

為了研究更高壓施壓狀態(tài)下粉體特性，以下為240MPa下三款LFP粉體的電導性及壓實密度特性參數(shù)； To research powder characteristics under more higher pressure loading status, the below are resistivity and press density parameters of LFP powder under 240MPa; 三款材料中高能量型、能量型及倍率型的電阻率依次降低；The resistivity characteristics of three types materials match with the particle size design.

不同包覆改性LCO分析Doping LCO Analysis

300MPa下，LCOZ粉末電阻率最小5.946Ω*m，電阻從小到大依次為LCOZ＜LCOA＜LCO＜LCOM，其中LCOM的組別實驗組效果最差；

300MPa下，LCOA粉末壓實密度最大達到4.58g/cc，壓實密度從小到大依次為LCOZ＜LCOM＜LCO＜LCOA;

壓實密度和壓力的關(guān)系趨勢一致；

鈉電池正極電阻分析 Na-ion Cell Cathode Materials Analyse

針對鈉離子電池正極材料的材料導電性進行測試分析，以下為一款聚陰離子正極粉體（NX系列）混合兩種不同導電添加劑的電導性評估. The below is the resistivity of polyanionic-based cathode materials (NX series) mixed two conductive additives:

NX+1.3%導電劑B的整體電導性比NX+1%導電劑A的效果好很多；The whole resistivity of NX+1.3%B more better than NX+1% A;

三元材料電阻率評估NCM Resistivity Analysis

針對不同三元材料的電導性測試應(yīng)用，粉末電阻測試系統(tǒng)能有效地區(qū)分不同材料電阻率；Test system able to measure different type NCM material resistivity;

另外，可以看出粉末電阻率與極片電阻呈相同變化趨勢。Additionally, we can see that resistivity and electrode resistance shows the same trend.

石墨粉料生產(chǎn)穩(wěn)定性評估Stability of Graphite production

為了提高電池的一致性與可靠性，傳統(tǒng)克容量、顆粒度、BET等檢測已經(jīng)不足以保證材料的一致性。所以，對于評價材料一致性非常有用的粉末電阻率就變得越來越重要。In order to improve the consistency and reliability of the battery, the traditional specific capacity, particle size, BET and other tests are not enough to ensure the consistency of the material. Therefore, powderresistivity test becomes more and more important.

右圖展現(xiàn)了不同生產(chǎn)批次石墨粉料的電阻數(shù)據(jù)，用于材料生產(chǎn)穩(wěn)定性監(jiān)控。 The picture show the resistivity data of different graphite batches, which is used to monitor the stability of material production.

粉末、極片與電芯電阻關(guān)聯(lián)分析Correlation analysis of powder, electrode and Cell

為了加快電池研發(fā)效率，希望通過零部件的性能來預(yù)測電芯性能，比如：利用粉末電阻、極片電阻來預(yù)測電芯內(nèi)阻、功率等表現(xiàn)；By analyzing the resistance components of different levels(Such as powder, electrode ) to predict the performance of full cell.

以下示例為NCM811材料在不同導電添加劑量下粉末、極片及電芯內(nèi)阻的對應(yīng)結(jié)果。The corresponding results of powder, electrode and cell resistance of NCM811 with different conductive additive.

審核編輯黃宇