Lithium ion secondary battery
An object of the present invention is to provide a lithium ion secondary battery enabling improvement of output characteristics at the time of charge and discharge at low temperature and at room temperature. A lithium ion secondary battery according to the present invention for achieving the above object includes a positive electrode plate ( 11 ) including a positive electrode mix layer, and a negative electrode plate ( 12 ) including a negative electrode mix layer ( 45 ). The negative electrode mix layer ( 45 ) contains a graphite-type material ( 42 ), metal oxide ( 44 ), and a conductive assistant ( 43 ). The conductive assistant ( 43 ) is a carbon material that does not dope or dedope lithium ions, and a mixing ratio of the conductive assistant ( 43 ) is 0.4 weight % or more and less than 1.2 weight % of weight of the negative electrode mix layer ( 45 ).
1. A lithium ion secondary battery comprising:
a positive electrode plate comprising a positive electrode mix layer; and
a negative electrode plate comprising a negative electrode mix layer,
wherein the negative electrode mix layer comprises a graphite material, metal oxide, and a conductive assistant,
wherein the conductive assistant in the negative electrode mix layer is a carbon material that does not dope or dedope lithium ions, and a mixing ratio of the conductive assistant in the negative electrode mix layer is (i) 0.4 weight % or more and (ii) less than 1.0 weight % of weight of the negative electrode mix layer,
wherein a particle diameter of the graphite material is larger than a particle diameter of the conductive assistant and a particle diameter of the conductive assistant is larger than a particle diameter of the metal oxide, and
the metal oxide serves as an electric resistor and has a particle diameter insufficient for electrons to pass through the metal oxide.
2. The lithium ion secondary battery according to claim 1 , wherein the metal oxide is iron oxide.
3. The lithium ion secondary battery according to claim 1 , wherein the amount of the metal oxide is 0.1 weight % or more and 3.0 weight % or less of the weight of the negative electrode mix layer.
4. The lithium ion secondary battery according to claim 1 , wherein the conductive assistant is carbon black.
5. A lithium ion secondary battery comprising:
a first electrode plate comprising a positive electrode mix layer; and
a second electrode plate comprising a negative electrode mix layer,
wherein the negative electrode mix layer comprises a graphite material, metal oxide, and a conductive assistant,
wherein the conductive assistant in the negative electrode mix layer is a carbon material that does not dope or dedope lithium ions,
wherein a particle diameter of the graphite material is larger than a particle diameter of the conductive assistant, and a particle diameter of the conductive assistant is larger than a particle diameter of the metal oxide, and
wherein the metal oxide serves as an electric resistor and has a particle diameter insufficient for electrons to pass through the metal oxide and the amount of the metal oxide is 0.1 weight % or more and 3.0 weight % or less of the weight of the negative electrode mix layer.
6. The lithium ion secondary battery according to claim 5 , wherein a mixing ratio of the conductive assistant is 0.4 weight % or more and 1.0 weight % or less of the weight of the negative electrode mix layer.
7. The lithium ion secondary battery according to claim 5 , wherein the metal oxide is iron oxide.
8. The lithium ion secondary battery according to claim 5 , wherein the conductive assistant is carbon black.