Specializing in the production of lithium battery cathode material precursors, the enterprise’s product quality stability directly affects the cycle life and safety of downstream battery enterprises. It once suffered a loss of over 10 million yuan due to customer returns caused by excessive impurity content (iron ion content >5ppm) in a batch of products. To solve quality control pain points, the enterprise built a full-chain quality control system: In the procurement link, it conducted full-index incoming inspection on upstream raw materials such as nickel, cobalt, and manganese, using ICP-MS (Inductively Coupled Plasma Mass Spectrometry) to detect impurity content, ensuring harmful impurities such as iron and copper were ≤2ppm. It also established a supplier quality rating system, eliminating 3 suppliers with unstable quality. In the production link, 6 quality inspection points were set at key nodes including reaction, washing, and drying, real-time monitoring parameters such as particle size distribution, purity, and moisture. Automated sampling equipment was adopted to reduce human errors, with test data uploaded to the MES system in real time. In the delivery link, sampling inspection was conducted for each batch of finished products, issuing test reports covering 32 indicators, and establishing product traceability codes linking raw material procurement batches, production process parameters, and test results to achieve full traceability “from raw materials to finished products”. In addition, a quality improvement team was set up to optimize processes based on problems found in testing, such as improving the washing process to stably control product impurity content below 1ppm. After the implementation of the quality control system, the product batch qualification rate increased from 92% to 99.8%, and customer complaint rate dropped by 85%, successfully entering the supply chain of leading battery enterprises such as CATL and BYD.