US 12,334,510 B2
Lithium secondary battery
Tomohiro Harada, Osaka Fu (JP)
Assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD., Osaka (JP)
Appl. No. 17/261,355
Filed by Panasonic Intellectual Property Management Co., Ltd., Osaka (JP)
PCT Filed Feb. 20, 2019, PCT No. PCT/JP2019/006355
§ 371(c)(1), (2) Date Jan. 19, 2021,
PCT Pub. No. WO2020/026483, PCT Pub. Date Feb. 6, 2020.
Claims priority of application No. 2018-142298 (JP), filed on Jul. 30, 2018.
Prior Publication US 2021/0280919 A1, Sep. 9, 2021
Int. Cl. H01M 10/0587 (2010.01); H01M 4/02 (2006.01); H01M 4/131 (2010.01); H01M 4/485 (2010.01); H01M 10/052 (2010.01); H01M 10/0525 (2010.01); H01M 50/531 (2021.01)
CPC H01M 10/0587 (2013.01) [H01M 4/131 (2013.01); H01M 4/485 (2013.01); H01M 10/052 (2013.01); H01M 10/0525 (2013.01); H01M 50/531 (2021.01); H01M 2004/028 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A lithium secondary battery, comprising: a wound electrode group; a non-aqueous electrolyte, and a bottom-closed cylindrical battery case,
the wound electrode group including:
a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, a positive electrode lead electrically connected to the positive electrode, and a negative electrode lead electrically connected to the negative electrode, the positive electrode and the negative electrode being wound with the separator between the positive electrode and the negative electrode, wherein
the negative electrode is an electrode on which lithium metal deposits during charge,
the positive electrode includes a positive electrode mixture layer containing a positive electrode active material, and a positive electrode current collector;
the positive electrode active material includes a composite oxide containing lithium and a transition metal;
a molar ratio: MLi/MTM of a total lithium amount per unit area MLi in the positive electrode and the negative electrode to a transition metal amount per unit area MTM in the positive electrode is 1.1 or less;
the negative electrode includes a negative electrode current collector;
the negative electrode current collector is larger in area than the positive electrode mixture layer;
in the wound electrode group in an unwound state,
a center line dividing the positive electrode mixture layer along a winding direction into two halves and a center line dividing the negative electrode current collector along the winding direction into two halves are not on a same straight line;
the negative electrode lead is connected at its one end to a non-facing region not facing the positive electrode mixture layer of the negative electrode current collector,
the wound electrode group has a cylindrical shape, and
the wound electrode group is disposed in the bottom-closed cylindrical battery case.