Secondary battery with separator having a solid electrolyte, battery pack, and vehicle
According to one embodiment, a separator is provided. The separator is selectively permeable to monovalent cations and includes a first surface and a second surface which is a reverse surface to the first surface. A contact angle θ1 of the first surface with respect to an aqueous electrolyte is different from a contact angle θ2 of the second surface with respect to the aqueous electrolyte.
1. A secondary battery comprising:
a positive electrode;
a negative electrode comprising a negative electrode active material-containing layer;
an aqueous electrolyte; and
a separator, the separator being selectively permeable to monovalent cations, not substantially permeable to anions, and comprising a first principal surface, a second principal surface, and at least one selected from the group consisting of an oxide type solid electrolyte, a polymer type solid electrolyte, a glass electrolyte, and a lithium ion exchange membrane,
wherein
at least a part of the first principal surface faces the negative electrode active material-containing layer,
a contact angle θ1 of the first principal surface with respect to the aqueous electrolyte is 90°≤θ1<180°,
the positive electrode comprises a positive electrode active material-containing layer,
the second principal surface is in contact with the positive electrode active material-containing layer, and
the contact angle θ1 is larger than a contact angle θ2 of the second principal surface with respect to the aqueous electrolyte.
2. The secondary battery according to claim 1 , wherein a whole principal surface of the negative electrode active material-containing layer is in contact with the first principal surface of the separator.
3. The secondary battery according to claim 1 , wherein the contact angle θ2 is 10°≤θ2<90°.
4. The secondary battery according to claim 1 , wherein the first principal surface comprises a hydrophobic group.
5. The secondary battery according to claim 1 , wherein the separator comprises at least one selected from the group consisting of a glass electrolyte and a lithium ion exchange membrane.
6. The secondary battery according to claim 5 , wherein the separator is formed from a glass electrolyte.
7. The secondary battery according to claim 1 , wherein the aqueous electrolyte comprises at least one selected from a chloride ion (Cl − ), a hydroxide ion (OH − ), a sulfate ion (SO 4 2− ), a nitrate ion (NO 3 − ), and an acetate ion (CH 3 COO − ).
8. A battery pack comprising the secondary battery according to claim 1 .
9. The battery pack according to claim 8 , further comprising an external power distribution terminal and a protective circuit.
10. The battery pack according to claim 8 , comprising plural of secondary batteries, wherein the secondary batteries are electrically connected in series, in parallel, or in combination of series connection and parallel connection.
11. A vehicle comprising the battery pack according to claim 8 .
12. The vehicle according to claim 11 , which comprises a mechanism configured to convert kinetic energy of the vehicle into regenerative energy.
13. The secondary battery according to claim 1 , wherein the separator is formed from an oxide type solid electrolyte.
14. The secondary battery according to claim 1 , wherein the separator is formed from a polymer type solid electrolyte.
15. The secondary battery according to claim 1 , wherein the separator is formed from a lithium ion exchange membrane.
16. The secondary battery according to claim 1 , wherein the at least a part of the first principal surface is in direct contact with the negative electrode active material-containing layer.