Adhesive composition for electrochemical device, adhesive layer for electrochemical device, and electrochemical device
Provided is an adhesive composition for an electrochemical device capable of forming an adhesive layer that has excellent adhesiveness in electrolysis solution and can improve electrical characteristics of an electrochemical device. The adhesive composition can be used for adhering an electrode assembly and a casing to one another. The adhesive composition contains organic particles having a core-shell structure including a core portion and a shell portion that partially covers an outer surface of the core portion. A polymer of the core portion has a degree of swelling in electrolysis solution of at least a factor of 5 and no greater than a factor of 30, whereas a polymer of the shell portion has a degree of swelling in electrolysis solution of greater than a factor of 1 and no greater than a factor of 4.
1. A lithium ion secondary battery comprising
an electrode assembly, an electrolysis solution, and a casing that houses the electrode assembly and the electrolysis solution, wherein
the electrode assembly and the casing are adhered to one another through an adhesive layer obtained using an adhesive composition comprising
organic particles having a core-shell structure including a core portion and a shell portion that partially covers an outer surface of the core portion, wherein
the core portion is formed from a polymer having a degree of swelling (S factor based on weight) of at least 5 and no greater than 30, and
the shell portion is formed from a polymer having a degree of swelling (S factor based on weight) of greater than 1 and no greater than 4, wherein
the degree of swelling (S factor based on weight) is measured using an electrolysis solution having an SP value of 12.8 (cal/cm 3 ) 1/2 that is obtained by dissolving LiPF 6 as a supporting electrolyte with a concentration of 1 mol/L in a mixed solvent of ethylene carbonate, diethyl carbonate, and vinylene carbonate with volume mixing ratio of 68.5:30:1.5.
2. The lithium ion secondary battery of claim 1 , wherein
the polymer forming the core portion has a glass transition temperature of at least 0° C. and no higher than 150° C., and
the polymer forming the shell portion has a glass transition temperature of at least 50° C. and no higher than 200° C.
3. The lithium ion secondary battery of claim 1 , wherein
the adhesive composition further comprising
a binder having a glass transition temperature of at least 50° C. and no higher than 0° C.
4. A lithium ion capacitor comprising
an electrode assembly, an electrolysis solution, and a casing that houses the electrode assembly and the electrolysis solution, wherein
the electrode assembly and the casing are adhered to one another through an adhesive layer obtained using an adhesive composition comprising
organic particles having a core-shell structure including a core portion and a shell portion that partially covers an outer surface of the core portion, wherein
the core portion is formed from a polymer having a degree of swelling (S factor based on weight) of at least 5 and no greater than 30, and
the shell portion is formed from a polymer having a degree of swelling (S factor based on weight) of greater than 1 and no greater than 4, wherein
the degree of swelling (S factor based on weight) is measured using an electrolysis solution having an SP value of 12.8 (cal/cm 3 ) 1/2 that is obtained by dissolving LiPF 6 as a supporting electrolyte with a concentration of 1 mol/L in a mixed solvent of ethylene carbonate, diethyl carbonate, and vinylene carbonate with volume mixing ratio of 68.5:30:1.5.
5. The lithium ion capacitor of claim 4 , wherein
the polymer forming the core portion has a glass transition temperature of at least 0° C. and no higher than 150° C., and
the polymer forming the shell portion has a glass transition temperature of at least 50° C. and no higher than 200° C.
6. The lithium ion capacitor of claim 4 , wherein
the adhesive composition further comprising
a binder having a glass transition temperature of at least 50° C. and no higher than 0° C.
7. An electric double-layer capacitor comprising
an electrode assembly, an electrolysis solution, and a casing that houses the electrode assembly and the electrolysis solution, wherein
the electrode assembly and the casing are adhered to one another through an adhesive layer obtained using an adhesive composition comprising
organic particles having a core-shell structure including a core portion and a shell portion that partially covers an outer surface of the core portion, wherein
the core portion is formed from a polymer having a degree of swelling (S factor based on weight) of at least 5 and no greater than 30, and
the shell portion is formed from a polymer having a degree of swelling (S factor based on weight) of greater than 1 and no greater than 4, wherein
the degree of swelling (S factor based on weight) is measured using an electrolysis solution having an SP value of 11.9 (cal/cm 3 ) 1/2 that is obtained by dissolving tetraethylammonium tetrafluoroborate as a supporting electrolyte with a concentration of 1 mol/L in acetonitrile as a solvent.
8. The electric double-layer capacitor of claim 7 , wherein
the polymer forming the core portion has a glass transition temperature of at least 0° C. and no higher than 150° C., and
the polymer forming the shell portion has a glass transition temperature of at least 50° C. and no higher than 200° C.
9. The electric double-layer capacitor of claim 7 , wherein
the adhesive composition further comprising
a binder having a glass transition temperature of at least −50° C. and no higher than 0° C.