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CN-115349190-B - Secondary battery

CN115349190BCN 115349190 BCN115349190 BCN 115349190BCN-115349190-B

Abstract

The secondary battery comprises a positive electrode containing a lithium-nickel composite oxide, a negative electrode containing a lithium-titanium composite oxide, and an electrolyte containing a dinitrile compound and a carboxylic acid ester. The ratio of the capacity of the positive electrode per unit area to the capacity of the negative electrode per unit area is 100% to 120%, and the ratio of the number of moles of the dinitrile compound to the number of moles of the carboxylic acid ester is 1% to 4%.

Inventors

  • Zong Ganggaomin
  • HARAMOTO MASAHIRO
  • Between assistant is of a specified duration, intelligence is beautiful
  • Bridging extension tree

Assignees

  • 株式会社村田制作所

Dates

Publication Date
20260508
Application Date
20201116
Priority Date
20200331

Claims (7)

  1. 1. A secondary battery is provided with: a positive electrode comprising a lithium nickel composite oxide; A negative electrode comprising a lithium-titanium composite oxide, and An electrolyte solution containing a dinitrile compound and a carboxylic acid ester, The ratio of the capacity of the positive electrode per unit area to the capacity of the negative electrode per unit area is 100% or more and 120% or less, The ratio of the number of moles of the dinitrile compound to the number of moles of the carboxylic acid ester is 1% or more and 4% or less, The lithium nickel composite oxide contains lithium, nickel and at least one other element other than nickel in the elements of groups 2 to 15 of the long period periodic table as constituent elements, The ratio of the number of moles of nickel to the sum of the number of moles of nickel and the number of moles of the other elements is 80% or more.
  2. 2. The secondary battery according to claim 1, wherein, The lithium titanium composite oxide contains at least one compound represented by the following formula (1), formula (2) and formula (3), respectively, Li[Li x M1 （1-3x）/2 Ti （3＋x）/2 ]O 4 ...(1) In the formula (1), M1 is at least one of Mg, ca, cu, zn and Sr, x is more than or equal to 0 and less than or equal to 1/3, Li[Li y M2 1-3y Ti 1＋2y ]O 4 ...(2) In the formula (2), M2 is at least one of Al, sc, cr, mn, fe, ga and Y, Y is more than or equal to 0 and less than or equal to 1/3, Li[Li 1/3 M3 z Ti （5/3）-z ]O 4 ...(3) In the formula (3), M3 is at least one of V, zr and Nb, and z is more than or equal to 0 and less than or equal to 2/3.
  3. 3. The secondary battery according to claim 1 or 2, wherein, The dinitrile compound comprises at least one of succinonitrile, glutaronitrile and adiponitrile, The carboxylic acid ester comprises at least one of ethyl propionate and propyl propionate.
  4. 4. The secondary battery according to claim 1 or 2, wherein, The electrolyte solution may comprise a solvent and, The solvent comprises the carboxylic acid ester, The content of the carboxylic acid ester in the solvent is 50% by weight or more and 90% by weight or less.
  5. 5. The secondary battery according to claim 1 or 2, wherein, And a separator interposed between the positive electrode and the negative electrode, The positive electrode and the negative electrode are alternately laminated with the separator interposed therebetween.
  6. 6. The secondary battery according to claim 1 or 2, wherein, The battery further comprises a flexible exterior member for accommodating the positive electrode, the negative electrode and the electrolyte.
  7. 7. The secondary battery according to claim 1 or 2, wherein, The secondary battery is a lithium ion secondary battery.

Description

Secondary battery Technical Field The present technology relates to a secondary battery. Background Since various electronic devices such as mobile phones are popular, secondary batteries are being developed as small-sized and lightweight power sources capable of obtaining high energy density. The secondary battery includes a positive electrode, a negative electrode, and an electrolyte, and various studies have been made on the structure of the secondary battery. Specifically, in order to improve low-temperature output characteristics and the like, the operating voltage of the negative electrode is 1.2V or more with respect to the lithium potential, and the electrolyte contains a carboxylic acid ester such as methyl acetate (for example, refer to patent documents 1 and 2). In order to suppress expansion of the secondary battery, the negative electrode contains spinel-type lithium titanate, and the electrolyte contains ethyl acetate or the like (for example, refer to patent document 3). In order to improve electrochemical characteristics over a wide temperature range, the anode includes lithium titanate as an anode active material, and the electrolyte includes an isocyanate compound (for example, refer to patent document 4.). In order to reduce the generation of gas at the time of high-temperature use, the negative electrode contains titanium oxide, and the electrolyte contains a dinitrile compound (for example, refer to patent document 5). Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2010-205563 Patent document 2 International publication No. 2009/110490 pamphlet Patent document 3 Japanese patent application laid-open No. 2013-229341 Patent document 4 International publication No. 2015/030190 pamphlet Patent document 5 International publication No. 2015/033620 pamphlet Disclosure of Invention Various studies have been made on the improvement of the performance of secondary batteries, but there is room for improvement because not only the energy density but also the expansion characteristics and the charging characteristics are insufficient. The present technology has been made in view of the above-described problems, and an object thereof is to provide a secondary battery that can obtain excellent expansion characteristics and excellent charging characteristics while securing energy density. A secondary battery according to one embodiment of the present technology includes a positive electrode including a lithium-nickel composite oxide, a negative electrode including a lithium-titanium composite oxide, and an electrolyte including a dinitrile compound and a carboxylate, wherein the ratio of the capacity of the positive electrode per unit area to the capacity of the negative electrode per unit area is 100% or more and 120% or less, and the ratio of the number of moles of the dinitrile compound to the number of moles of the carboxylate is 1% or more and 4% or less. The "lithium-nickel composite oxide" is a generic term for oxides containing lithium and nickel as constituent elements, and the "lithium-titanium composite oxide" is a generic term for oxides containing lithium and titanium as constituent elements. Details of each of the lithium nickel composite oxide and the lithium titanium composite oxide will be described later. According to the secondary battery of one embodiment of the present technology, the positive electrode includes a lithium nickel composite oxide, the negative electrode includes a lithium titanium composite oxide, and the electrolyte includes a dinitrile compound and a carboxylate. The ratio of the respective capacities of the positive electrode and the negative electrode is within the above range, and the ratio of the respective molar numbers of the dinitrile compound and the carboxylic acid ester is within the above range. Therefore, excellent expansion characteristics and excellent charging characteristics can be obtained while ensuring energy density. The effects of the present technology are not necessarily limited to those described herein, and may be any of a series of effects related to the present technology described below. Drawings Fig. 1 is a perspective view showing the structure of a secondary battery according to an embodiment of the present technology. Fig. 2 is a sectional view showing the structure of the battery element shown in fig. 1. Fig. 3 is a perspective view showing the structure of a secondary battery according to modification 1. Fig. 4 is a sectional view showing the structure of the battery element shown in fig. 3. Fig. 5 is a block diagram showing a configuration of an application example of the secondary battery. Detailed Description An embodiment of the present technology will be described in detail below with reference to the drawings. The sequence of the description is as follows. 1. Secondary battery 1-1 Structure 1-2. Action 1-3 Method of manufacture 1-4 Actions and effects 2. Modification example