【作者】 陈伟；

【导师】 余萍； 庄严；

【作者基本信息】 四川大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 锂离子电池作为主要的储能与供能系统,电池内部热状态及时的准确评估是锂离子电池规模化使用和高效化使用的安全保障措施之一。因此电池内部温度的监测技术就显得格外重要。本文开展了钛酸铜钙(Ca Cu₃Ti₄O₁₂,CCTO)基陶瓷作为锂离子电池内置式温度传感器阵列的研究,旨在借助钛酸铜钙(Ca Cu₃Ti₄O₁₂)热敏陶瓷所具有NTC（negative temperature coefficient）热敏电阻效应来实现对锂离子电池工作状态的实时原位监测。本文研究工作选取了在锂离子电池工作温区具有高热敏常数B值的CCTO材料作为温度传感器的敏感材料。采用溶胶凝胶工艺制备了CCTO陶瓷粉体,电子陶瓷制备技术制备了CCTO陶瓷,研究了陶瓷粉体合成温度对粉体结构和粒径的影响以及不同烧结温度对CCTO陶瓷结构、形貌和NTC特性的影响。优化了陶瓷粉体合成工艺和陶瓷制备工艺。通过流延片的成型工艺,本研究制备出了尺寸2.5 mm×2.5 mm,厚度为110微米的CCTO小型片式陶瓷。将其作为敏感元,以PI（polyimide）膜为柔性基底,通过热压封装技术制备了4×4和3×3传感器阵列原型。能进行多点监控的柔性温度传感器阵列。并将所制备的传感器阵列植入软包电池,在静态条件下研究了传感器阵列植入电池后的工作性能以及电池的电解液对所制备传感器阵列腐蚀性。本论文工作的主要结论如下:1.CCTO粉体化学合成工艺研究发现前期合成时总是同时伴随着二次相CuO,陶瓷粉体制备成陶瓷生坯分别经950℃、1000℃、1050℃和1100℃对CCTO陶瓷烧结均可以完全去除二次相。粒径测试的结果表明700℃预烧的粉体粒径小,粒径分布最窄,最有利于后续的流延工艺。2.CCTO陶瓷的烧结工艺研究表明,CCTO陶瓷电阻率和热敏系数与烧结温度显著相关。确定最佳烧结制度为在1000℃下烧结4 h后自然冷却,获得的相应样品具有高的电阻率ρ（6.633×10⁸Ω·cm）和热敏常数B（2455-11371）。研究了1000℃烧结温度下的CCTO热敏电阻线性度最小值为0.66%,迟滞最小值5.7%。3.采用流延工艺制备小批量样品,所制备样品在-50-180℃温度区间内有良好的NTC特性;热敏系数B_50-75为4266-4693;热敏系数B_75-100为3578-4376;热敏系数B_100-125为4199-4619;热敏系数B_125-150为5670-6237;热敏系数B_150-175为7996-9725。均高于已报导的尖晶石结构的材料性能。批量样品的线性度最小值为1.2%;迟滞最小值为0.97%。4.通过热压技术制备的传感器阵列可与电池的封装工艺兼容。热压密封完好的传感器阵列原型能够阻止电解液的渗透。六氟磷酸锂电解液对传感器阵列原型的腐蚀主要表现在两个方面:密封不严密的地方可能会发生电解液的渗透;电解液会引起PI膜的力学性能的改变。在电解液腐蚀28天以内,随着腐蚀时间的增加,PI膜的抗形变能力减弱,脆性增加。这种改变在15天以后趋于缓慢,本论文工作时间段内没有观察到PI膜因被腐蚀而毁坏现象。更多还原

【Abstract】 Evaluating the internal thermal state of batteries accurately is one of the safety measures for using lithium-ion batteries in the large-scale and efficiently.This thesis conducts research on Ca Cu₃Ti₄O₁₂（CCTO）based ceramics as an internal temperature sensor array for lithium-ion batteries,aiming to achieve real-time in situ monitoring of the working status of lithium-ion batteries using the NTC（negative temperature coefficient）thermistor effect of CCTO thermosensitive ceramics.This study employed CCTO material,which shows high thermal sensitivity constant B value in the operating temperature range of lithium-ion batteries,as the sensitive material for temperature sensors.CCTO ceramic powders were prepared by sol gel process,and CCTO ceramics were prepared by traditional ceramic preparation process.The synthesis process of ceramic powder and the preparation and sintering process of ceramics have been optimized.Through the forming process of cast sheets,small chip CCTO ceramics prepared with a size of 2.5 mm×2.5 mm and a thickness of 110μm.Using it as a sensitive element and PI film as a flexible substrate,4×4 and 3×3 sensor array prototypes.were prepared by hot pressing packaging technology.And the prepared sensor array was implanted into the soft pack battery to achieve multi-point temperature monitoring.and the working performance of the sensor array implanted into the battery and the corrosion of the battery electrolyte on the prepared sensor array were studied under static and dynamic conditions.The brief summaries of the work are as follows:1.It is found that the CCTO powder synthesized by sol-gel process showed body centered cubic perovskite phase structure with a little CuO as the secondary phases.Anyway,after sintering at 950℃,1000℃,1050℃,and1100℃,the CCTO ceramics showed pure body centered cubic perovskite phase structure.The results of particle size testing indicated that the powder synthesized at 700℃showed the smallest particle size and the narrowest particle size distribution.2.The resistivity and thermal sensitivity coefficient B values of CCTO ceramics were significantly correlated with the sintering temperature.The most proper sintering system would be cooling naturally after sintering at1000℃for 4 hours,and the corresponding samples obtained show high resistivityρ（6.633×10⁸Ω·cm）and thermal constant B（2455-11371）.The minimum linearity value of CCTO thermistor was 0.66%,and the minimum hysteresis value was 5.7%.3.Small batch samples were prepared by using tape casting technology,and the prepared samples exhibited satisfied NTC characteristics within the temperature range of-50-180℃;The thermal sensitivity coefficient B_50-75is4266-4693;B_75-100is 3578-4376;B_100-125is 4199-4619;B_125-150is 5670-6237;B_150-175is 7996-9725.The material performance is higher than that of the reported spinel structure materials.The minimum linearity value of batch samples is 1.2%;The minimum hysteresis value is 0.97%.4.The sensor array prepared by hot pressing technology can be compatible with the packaging process of the battery.The prototype of a sensor array with good thermal sealing can prevent the penetration of electrolyte.The corrosion of the sensor array prototype result from lithium hexafluorophosphate electrolyte is mainly manifested in two aspects:electrolyte penetration may occur in areas with loose sealing and electrolyte can cause changes in the mechanical properties of the PI membrane.of electrolyte corrosion,as the corrosion time increases within the first 28 days,the anti-deformation ability of the PI film would be getting weakened and friable.The changes tend to slow down after 15 days,and no damage to the PI film due to corrosion was observed during the working period of present work.更多还原