Secondary battery
The object is to provide a secondary battery with higher performance, and especially to provide a secondary battery having low impedance. An exemplary embodiment of the invention is a secondary battery, comprising an electrode assembly in which a positive electrode and a negative electrode are oppositely disposed, an electrolyte liquid, and a package which encloses the electrode assembly and the electrolyte liquid inside; wherein the negative electrode is formed by binding a negative electrode active substance to a negative electrode collector with a negative electrode binder; and wherein the electrolyte liquid comprises a fluorine-containing cyclic ether compound.
1. A secondary battery, comprising an electrode assembly in which a positive electrode and a negative electrode are oppositely disposed, an electrolyte liquid, and a package which encloses the electrode assembly and the electrolyte liquid inside;
wherein the negative electrode is formed by binding a negative electrode active substance to a negative electrode collector with a negative electrode binder;
wherein the electrolyte liquid comprises a fluorine-containing cyclic ether compound represented by the following formulae (3)
wherein, in formula (3), R 15 to R 24 are each independently selected from among hydrogen atom, fluorine atom, or fluorine-substituted or non-substituted alkyl groups, and at least one of R 15 to R 24 is selected from fluorine atom or fluorine-substituted alkyl groups;
wherein the electrolyte liquid further comprises a linear or cyclic carbonate; and
wherein a content of the fluorine-containing cyclic ether compound is 1 to 30 mass % with respect to a total amount of the fluorine-containing cyclic ether compound and the carbonate.
2. The secondary battery according to claim 1 , wherein the fluorine-containing cyclic ether compound is a compound in which at least one of hydrogen atoms in tetrahydropyran is substituted by fluorine atom.
3. The secondary battery according to claim 1 , wherein the negative electrode active substance comprises at least one selected from among a metal (a) that can be alloyed with lithium, a metal oxide (b) that can absorb and desorb lithium ion, and a carbon material (c) that can absorb and desorb lithium ion.
4. The secondary battery according to claim 3 , wherein the negative electrode active substance comprises at least the metal (a).
5. The secondary battery according to claim 3 , wherein the negative electrode active substance comprises at least metal oxide (b).
6. The secondary battery according to claim 3 , wherein the negative electrode active substance comprises at least carbon material (c).
7. The secondary battery according to claim 3 , wherein the negative electrode active substance comprises at least metal oxide (b), and
wherein all or a part of the metal oxide (b) has an amorphous structure.
8. The secondary battery according to claim 3 , wherein the negative electrode active substance comprises at least metal (a) and metal oxide (b), and
wherein metal oxide (b) is an oxide of a metal which constitutes the metal (a).
9. The secondary battery according to claim 3 , wherein the metal (a) is silicon.
10. The secondary battery according to claim 3 , wherein the negative electrode active substance comprises at least metal (a) and metal oxide (b), and
wherein all or a part of the metal (a) is dispersed in the metal oxide (b).
11. The secondary battery according to claim 1 , wherein the negative electrode binder is a polyimide or a polyamide-imide.
12. The secondary battery according to claim 1 , wherein the electrode assembly has a planar stacking conformation.
13. The secondary battery according to claim 1 , wherein the package is an aluminum lamination film.
14. The secondary battery according to claim 1 , wherein the electrolyte liquid further comprises the linear carbonate.
15. The secondary battery according to claim 1 , wherein the electrolyte liquid further comprises the cyclic carbonate.
16. The secondary battery according to claim 14 , wherein the linear carbonate comprises at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and dipropyl carbonate (DPC).
17. The secondary battery according to claim 15 , wherein the cyclic carbonate comprises at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC).
18. The secondary battery according to claim 1 , wherein the fluorine-containing cyclic ether compound comprises at least one compound in which at least one of hydrogen atoms in a compound selected from among tetrahydropyran, 2-methyltetrahydropyran, 3-methyltetrahydropyran and 4-methyltetrahydropyran is substituted by fluorine atom.
19. The secondary battery according to claim 1 , wherein a content of the fluorine-containing cyclic ether compound is 5 to 20 mass % with respect to a total amount of the fluorine-containing cyclic ether compound and the carbonate.