Secondary battery, battery pack, and vehicle
In general, according to one embodiment, a secondary battery includes a positive electrode and a nonaqueous electrolyte. The positive electrode includes a sulfur-containing layer provided on at least a part of a positive electrode active material-containing layer. The nonaqueous electrolyte includes a sulfur-containing compound consisting of at least one of a sulfur-containing imide compound or a sultone compound, or consisting of at least one of a sulfur-containing imide compound, a sultone compound or a propanesulfonic acid ester. The secondary battery satisfies 1×10 −6 ≤E/A≤9×10 −4 . A denotes a mass of sulfur atoms per unit volume (g/m 3 ) of the sulfur-containing layer. E denotes a concentration (mol/L) of the sulfur-containing compound in the nonaqueous electrolyte.
1 . A lithium ion secondary battery, comprising:
a positive electrode;
a negative electrode; and
a nonaqueous electrolyte,
wherein
the positive electrode includes a positive electrode active material-containing layer and a sulfur-containing layer provided on at least a part of the positive electrode active material-containing layer and further comprising oxygen atoms and carbon atoms,
the nonaqueous electrolyte includes a sulfur-containing compound comprising a sultone compound and a propanesulfonic acid ester,
the lithium ion secondary battery satisfies expression (1):
1
×
1
0
-
6
≤
E
/
A
≤
9
×
1
0
-
4
(
1
)
where A denotes a mass of sulfur atoms per unit volume (g/m 3 ) of the sulfur-containing layer of the positive electrode, and E denotes a concentration (mol/L) of the sulfur-containing compound in the nonaqueous electrolyte,
wherein the positive electrode active material-containing layer contains as a positive electrode active material at least one compound allowing Li or Li ions to be inserted thereinto and extracted therefrom selected from the group consisting of manganese dioxide, iron oxides, copper oxides, nickel oxides, lithium manganese composite oxides, lithium nickel composite oxides, lithium cobalt composite oxides, lithium nickel cobalt composite oxides, lithium manganese cobalt composite oxides, lithium manganese nickel composite oxides having a spinel structure, lithium phosphorus oxides having an olivine structure, ferrous sulfates, vanadium oxides, LiNi x Co y M z O 2 where x+y+z=1, x≥0.8, and M consists of Mn and Al, and lithium nickel cobalt manganese composite oxides,
the negative electrode comprises a negative electrode active material-containing layer and a sulfur-containing layer provided on at least a part of the negative electrode active material-containing layer, and
the lithium ion secondary battery satisfies expression (2):
2
×
1
0
-
6
≤
E
/
D
≤
3
×
1
0
-
4
(
2
)
where D denotes a mass of sulfur atoms per unit volume (g/m 3 ) of the sulfur-containing layer of the negative electrode, and E denotes a concentration (mol/L) of the sulfur-containing compound in the nonaqueous electrolyte,
wherein the A is in a range of greater than 0 to 3500 g/m 3 , the E is in a range of greater than 0 to 4.5×10 −1 mol/L, and the D is in a range of greater than 0 to 6600 g/m 3 ,
wherein the negative electrode active material-containing layer includes at least one selected from the group consisting of a niobium titanium composite oxide represented by a general formula of Li x Ti 1-y M1 y Nb 2-z M2 z O 7+δ and a niobium titanium composite oxide represented by a general formula of Li x Ti 1-y M3 y+z Nb 2-z O 7−δ ,
where the M1 is at least one selected from the group consisting of Zr, Si, and Sn, the M2 is at least one selected from the group consisting of V, Ta, and Bi, the M3 is at least one selected from the group consisting of Mg, Fe, Ni, Co, W, Ta, and Mo, the x satisfies 0≤x≤5, the y satisfies 0≤y<1, the z satisfies 0≤z<2, and the δ satisfies −0.3≤δ≤0.3, and
wherein in a total ion chromatogram of the nonaqueous electrolyte according to gas chromatograph-mass spectrometry, a peak area value B of the propanesulfonic acid ester is 0.2 to 20 when a peak area value A of the sultone compound is set to 10.
2 . The lithium ion secondary battery according to claim 1 , wherein the propanesulfonic acid ester is at least one selected from the group consisting of methyl propanesulfonate, ethyl propanesulfonate, and propyl propanesulfonate.
3 . A battery pack comprising one or two or more of the lithium ion secondary battery according to claim 1 .
4 . The battery pack according to claim 3 , further comprising:
an external power distribution terminal; and
a protective circuit.
5 . The battery pack according to claim 3 , comprising two or more of the lithium ion secondary battery, wherein the two or more lithium ion secondary batteries are electrically connected in series, in parallel, or in a combination of in-series connection and in-parallel connection.
6 . A vehicle comprising the battery pack according to claim 5 .
7 . The vehicle according to claim 6 , comprising a mechanism configured to convert kinetic energy of the vehicle into regenerative energy.