Provided is a secondary battery which includes: one or more positive electrodes including a positive electrode active material layer; a plurality of negative electrodes including a first negative electrode including a silicon-based active material and a second negative electrode including a carbon-based active material; a separator; and an electrolyte, wherein the positive electrode and the negative electrode are alternately stacked with the separators interposed therebetween, and the ratio of weight of the silicon-based active material included in the first negative electrode and weight of the carbon-based active material included in the second negative electrode is in the range of 40:60 to 90:10.

Silicon-dominate battery electrodes, battery cells utilizing the silicon-dominate battery electrodes, and methods of manufacturing are disclosed. Such a battery electrode includes a current collector and an active material layer on the current collector. The active material layer comprises at least 50% silicon. In some embodiments, a ratio of a thickness of the current collector to a thickness of the active material layer is over 0.5, and a porosity of the active material layer is below 70%.

A secondary battery (10) of the present invention includes at least a positive electrode (11), a negative electrode (12), a separation layer (5) that spatially separates the positive electrode (11) and the negative electrode (12), and an ion conductor that is held between the positive electrode (11) and the negative electrode (12) and has a function of conducting ions between the positive electrode (11) and the negative electrode (12). In addition, in an initial stage of using the secondary battery (10), the secondary battery has a characteristic of a potential decrease rate of the positive electrode (11) immediately before completion of full discharging being larger than a potential increase rate of the negative electrode (12) immediately before the completion of full discharging and a characteristic of a potential increase rate of the positive electrode (11) immediately before completion of full charging being larger than a potential decrease rate of the negative electrode (12) immediately before the completion of full charging, and the secondary battery (10) is continuously used until a state in which the potential decrease rate of the positive electrode (11) immediately before the completion of full discharging becomes smaller than the potential increase rate of the negative electrode (12) immediately before the completion of full discharging.

This nonaqueous electrolyte secondary battery is provided with: an electrode body that comprises a positive electrode and a negative electrode; and a nonaqueous electrolyte solution that contains a nonaqueous solvent. The ratio of the capacity (Qn) of the negative electrode to the capacity (Qp) of the positive electrode, namely Qn/Qp is 1.4 or more; and the nonaqueous electrolyte solution contains, relative to the total volume of the nonaqueous solvent at 25° C., from 0.5% by volume to 10% by volume of methyl acetate and from 0.01 mole/L to 0.05 mole/L of lithium bisoxalato borate.

An electrochemical device includes a positive electrode plate, a negative electrode plate and a separator disposed between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive current collector and a positive active material layer disposed on the positive current collector. The positive active material layer includes a positive active material having lithium cobalt oxide. The negative electrode plate includes a negative current collector and a negative active material layer disposed on the negative current collector. The negative active material layer includes a negative active material. The electrochemical device satisfies 3≤100×(4.5−U)−10×(CB−1)≤10, CB=(A′×B′×C′)/(A×B×C). Increasing the CB value of the electrochemical device and reducing the charge cutoff voltage U, reduces volume expansion of the negative active material layer during charging and discharging, prevents the rise of the positive electrode potential from adversely affecting the positive active material, thereby improving the cycle performance of electrochemical device.

The present embodiment provides a lithium ion secondary battery including a positive electrode containing Li.sub.aNi.sub.xCo.sub.yM.sub.zO.sub.2 (0.9≤a≤1.2, 0.3≤x≤0.8, 0.2≤y+z≤0.7, where M is a metal element other than Li, Ni, and Co) as a positive active material, and a negative electrode containing non-graphitic carbon as a negative active material. In this lithium ion secondary battery, at a portion where the positive electrode and the negative electrode face each other, a basis weight (P) of the positive active material and a basis weight (N) of the negative active material satisfy a relational expression of 0.65≤P/N≤1.05.

The present application discloses a secondary battery and a battery module, a battery pack and an apparatus containing the secondary battery. The secondary battery comprises a positive electrode plate, a negative electrode plate, a separator and an electrolyte; the positive electrode plate comprising a positive electrode current collector and a positive electrode film disposed on at least one surface of the positive electrode current collector and comprising a positive electrode active material; the negative electrode plate comprising a negative electrode current collector and a negative electrode film disposed on at least one surface of the negative electrode current collector and comprising a negative electrode active material; wherein the positive electrode active material comprises one or more of lithium nickel cobalt manganese oxides and lithium nickel cobalt aluminium oxides; the negative electrode active material comprises a silicon-based material and a carbon material; and the secondary battery satisfies: 1.05≤K≤1.25.

A main object of the present disclosure is to provide a lithium solid battery in which the coulomb efficiency of the battery upon deposition and dissolution of a metal lithium is improved. The above object is achieved by providing a lithium solid battery comprising: an anode current collector, a solid electrolyte layer, a cathode active material layer, and a cathode current collector; wherein the lithium solid battery comprises a Li storing layer between the anode current collector and the solid electrolyte layer; an amount of Li storage of the Li storing layer to a cathode charging capacity is 0.13 or more; and a thickness of the Li storing layer is 83 μm or less.

A polymer includes a repeating unit represented by at least one of Formula 1a or Formula 1b: ##STR00001## wherein, in Formulae 1a or 1b, CY.sub.1 is a group represented by at least one of Formula 1-2 or Formula 1-4, CY.sub.2 is a group represented by Formula 1-3, and L.sub.1, L.sub.2, a1, and a2 are defined the same as in the specification, and ##STR00002## in Formulae 1-2, Formula 1-3, or 1-4, X, Y, R.sub.1, R.sub.2, R.sub.11 to R.sub.14, b1, b2, R.sub.21, R.sub.22, b21, b22, Z.sub.1, Z.sub.2, c1, and c2 are defined the same as in the specification.

A non-aqueous electrolyte secondary battery allows gas generated when an aqueous binder is used as a binder of a negative electrode active material to be effectively discharged from the electrode, and has small decrease of the battery capacity despite use over a long period of time. The non-aqueous electrolyte secondary battery has a positive electrode active material layer, a negative electrode active material layer, and a separator. The density of the negative electrode active material layer is 1.4 to 1.6 g/cm.sup.3, an electrolyte solution layer is disposed between at least one layer of the negative electrode active material layer and the positive electrode active material layer, and the separator, and the ratio of total thickness of the positive electrode, the negative electrode and the separator to total thickness of the positive electrode, the negative electrode, the separator and the electrolyte solution layer, is 0.85 or more and less than 1.0.