Study on the electrical-thermal properties of lithium-ion battery materials in the NCM622/graphite system.

The phenomenon of fire or even explosion caused by thermal runaway of lithium-ion power batteries poses a serious threat to the safety of electric vehicles. An in-depth study of the core-material thermal runaway reaction mechanism and reaction chain is a prerequisite for proposing a mechanism to prevent battery thermal runaway and enhance battery safety. In this study, based on a 24 Ah commercial Li(Ni0.6Co0.2Mn0.2)O2/graphite soft pack battery, the heat production characteristics of different state of charge (SOC) cathode and anode materials, the separator, the electrolyte, and their combinations of the battery were investigated using differential scanning calorimetry. The results show that the reaction between the negative electrode and the electrolyte is the main mode of heat accumulation in the early stage of thermal runaway, and when the heat accumulation causes the temperature to reach a certain critical value, the violent reaction between the positive electrode and the electrolyte is triggered. The extent and timing of the heat production behaviour of the battery host material is closely related to the SOC, and with limited electrolyte content, there is a competitive relationship between the positive and negative electrodes and the electrolyte reaction, leading to different SOC batteries exhibiting different heat production characteristics. In addition, the above findings are correlated with the battery failure mechanisms through heating experiments of the battery monomer. The study of the electro-thermal properties of the main materials in this paper provides a strategy for achieving early warning and suppression of thermal runaway in batteries.

Paediatric lymphoma in China: a clinicopathological study of 213 cases.

AIM: This retrospective study was conducted to evaluate information on paediatric lymphoma in China. METHODS: We reviewed the pathological files of patients less than 12 years of age with lymphoma in Shanghai Xinhua Hospital from January 1982 to June 2009. SPSS version 11.0 was used to analyse the results. RESULTS: Of the 213 subjects, 176 (82.6%) had non-Hodgkin's lymphoma (NHL) and 37 (17.4%) had Hodgkin's lymphoma (HL). All NHL cases had diffuse and high grade tumours, and 33.5% of these tumours primarily involved extra-nodal sites. Of the NHL cases, 56.6%, 43.3%, and 1.7% were derived from T, B, and null cells, respectively. Lymphoblastic lymphoma (LL, 50.6%), Burkitt's lymphoma (BL, 28.4%), and anaplastic large cell lymphoma (ALCL, 12.5%) comprised the majority of the NHL cases. A significant difference was found in the frequency of stage I/II cases between LL and ALCL. Paediatric HL resembled the disease in adults. CONCLUSIONS: Paediatric lymphoma in China is different from that in Western countries with respect to the incidence rate of HL and BL. The distribution pattern of NHL histological subtypes is more similar to that in Japan than that in Pakistan. These features suggest ethnic or geographic variations.

Langerhans cell histiocytosis of bone in children: a clinicopathologic study of 108 cases.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disease that is characterized by abnormal proliferation of pathological Langerhans cells (LCs). In this study, a total of 108 pediatric patients with LCH of bone were evaluated retrospectively for illustrating the clinicopathologic features of this disease, with a goal of improving the diagnosis, treatment, and prognosis. METHODS: A retrospective study was based on the clinical records and pathological data of 108 patients (13 days to 12 years of age) with LCH of bone from a single hospital. Hematoxylin-eosin stain and immunohistochemical stain were applied. The follow-up was conducted to June 2008. RESULTS: The peak age of the patients ranged between 3 years and 6 years (80.6%, 87/108), and male gender predominated. The most common clinical presentation was local pain, and the imaging findings commonly showed an isolated lytic lesion in the bone. Of the 108 patients, 79 (73.1%) had single bone involvement, 27 (25.0%) had multi-bone involvement (with or without related skin involvement), and 2 (1.8%) had multisystem involvement. Histologically, all the lesions revealed abnormal proliferation of pathological Langerhans cells along with an admixture of eosinophils, lymphocytes, and other inflammatory cells. The LCs have similar shape and are positive for cluster of differentiation 1a (CD1a) (100.0%, 60/60), S100 (90.0%, 54/60), CD68 (41.7%, 25/60), lysozyme (Lys) (40.0%, 24/60), and macrophage antigen compound (MAC) 387 (30.0%, 18/60); cytokeratin (CK) and epithelial membrane antigen (EMA) were negative. The overall survival rate was 98.0% at a median follow-up of 5 years. CONCLUSIONS: LCH of bone in children is predominant in males and usually shows as an isolated lytic lesion. Histologically, the lesions reveal abnormal proliferation of pathological Langerhans cells, admixed with various types of inflammatory cells. The patients have a good prognosis, except those with multi-system involvement.