The present invention discloses a high-efficiency working method for a battery energy storage system at low temperature. In the present invention, combined operation of two kinds of batteries is taken as an example to build an energy storage system framework at low temperature. A lithium iron phosphate battery and a lithium titanate battery are selected for combined operation to achieve complementary advantages of the two kinds of batteries; then, an energy storage system model for combined operation of the two kinds of batteries with the consideration of an impact of temperature on charging/discharging efficiency of the batteries is built; and finally, an optimal dispatching solution for a battery energy storage system composed of the lithium titanate battery and the lithium iron phosphate battery at low temperature is provided. By the above steps, the present invention achieves high-efficiency outputting of electricity of the battery energy storage system at low temperature, achieves complementary advantage of different kinds of batteries, and also ensures low overall cost.

Provided is a negative electrode active material for a lithium secondary battery including: a silicon oxide (SiO.sub.x, 0<x≤2) composite including an alkali metal or alkaline earth metal-containing phosphate; and an aluminum-containing phosphate.

This application provides a composite positive electrode material and a preparation method thereof, a secondary battery, a battery group including the secondary battery, and an electric apparatus including the secondary battery. The composite positive electrode material includes a lithium-rich metal oxide and a positive electrode active material covering at least a partial surface of the lithium-rich metal oxide, where the positive electrode active material is formed through in-situ reaction between a positive electrode active material precursor and a free lithium compound on the surface of the lithium-rich metal oxide.

Separator systems for electrochemical systems providing electronic, mechanical and chemical properties useful for applications including electrochemical storage and conversion. Separator systems include structural, physical and electrostatic attributes useful for managing and controlling dendrite formation and for improving the cycle life and rate capability of electrochemical cells including silicon anode based batteries, air cathode based batteries, redox flow batteries, solid electrolyte based systems, fuel cells, flow batteries and semisolid batteries. Separators include multilayer, porous geometries supporting excellent ion transport properties, providing a barrier to prevent dendrite initiated mechanical failure, shorting or thermal runaway, or providing improved electrode conductivity and improved electric field uniformity, as well as composite solid electrolytes with supporting mesh or fiber systems providing solid electrolyte hardness and safety with supporting mesh or fiber toughness and long life required for thin solid electrolytes without fabrication pinholes or operationally created cracks.

A lithium-sulfur battery cathode including conductive porous carbon particles vacuum infused with sulfur and a conductive collector substrate to which the sulfur infused porous carbon particles are deposited. The sulfur infused carbon particles are encapsulated by an encapsulation polymer, the encapsulation polymer having ionic conductivity, electronic conductivity, polysulfide affinity, or combinations thereof. A lithium-sulfur battery including the lithium-sulfur battery cathode, a lithium anode and an electrolyte disposed between the sulfur cathode and the lithium anode is also provided. Methods of producing the sulfur cathode for use in a lithium-sulfur battery by a hybrid vacuum-and-melt method are also provided.

A non-aqueous lithium power storage element that includes a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, the positive electrode having a positive electrode collector and a positive electrode active material layer that includes active carbon, and the non-aqueous lithium power storage element having configuration (1) and/or (2). (1) The negative electrode includes a negative electrode collector and a negative electrode active material layer (2) The non-aqueous electrolyte contains (A) LiPF.sub.6 and/or LiBF.sub.4, (B) an imide lithium salt, and (C) an oxalate-complex lithium salt, the ratio of the mass of component (C) to the total mass of components (A) and (B) being 1.0-10.0 mass %.

Processes are described for the direct or indirect electrochemical alkaliation of an alkali metal deficient electrochemically active material. The processes include an electrolysis step either during the alkaliation of the alkali metal deficient electrochemically active material on an electrode current collector (direct) or during the regeneration of a reducing agent used for the alkaliation of the electrochemically active material (indirect).

The present application relates to a battery module, and the battery module includes a first-type battery cell and a second-type battery cell at least connected in series, the first-type battery cell and the second-type battery cell are battery cells of different chemical systems, the first-type battery cell includes N first battery cell(s), the second-type battery cell includes M second battery cell(s), N and M are positive integers, a specific surface area of a positive active substance of the first battery cell is S1, a specific surface area of a positive active substance of the second battery cell is S2, and S1 and S2 satisfy: 1≤S1/S2≤60.

The present application relates to a battery module, comprising a first type of battery cells and a second type of battery cells electrically connected at least in series, wherein the first and second type of battery cells are battery cells of different chemical systems, the first type of battery cells comprises N first battery cells, the second type of battery cells comprises M second battery cells, and N and M are positive integers; a positive electrode plate of the second battery cell contains two or more positive electrode active materials, and when a dynamic SOC of the second battery cell is in a range from 90% to 98%, a change rate ΔOCV/ΔSOC in an OCV relative to the SOC of the second battery cell satisfies 3≤ΔOCV/ΔSOC≤9, in mV/% SOC, where SOC represents a charge state and OCV represents an open circuit voltage.

The present application relates to a battery module, comprising a first type of battery cells and a second type of battery cells electrically connected at least in series, wherein the first type of battery cells and the second type of battery cells are battery cells with different chemical systems, the first type of battery cells comprises N first battery cells, the second type of battery cells comprises M second battery cells, N and M are positive integers, the first battery cell comprises a first separator and a first electrolyte, the second battery cell comprises a second separator and a second electrolyte, a kinetic characteristic factor x1 of the first battery cell is: x1=1000×(ε1×r1)/(τ1×t1×θ1), a kinetic characteristic factor x2 of the second battery cell is: x2=1000×(ε2×r2)/(τ2×t2×θ2), and x1 and x2 satisfy: 0.01≤x1/x2≤160.