Charge and discharge system

Abstract

To restrain lithium deposition in a lithium-ion battery by highly accurate prediction of the deposition.SOLUTION: A charge and discharge system according to the present disclosure is configured to charge and discharge a lithium-ion secondary battery including a battery cell. The charge and discharge system includes: a first detection part that detects a voltage value across a first electrode and a second electrode of a battery cell having a first electrode serving as a cathode, a second electrode serving as an anode, a separator arranged between the first electrode and the second electrode, and a third electrode arranged between the second electrode and the separator; a second detection part that detects a voltage value across the first electrode and the third electrode; and a control part that controls charging and discharging of the battery cell. The charge and discharge system starts charging of the battery cell with a predetermined first charging current, and when a difference between a first voltage value detected by the first detection part and a second voltage value detected by the second detection part becomes a predetermined threshold or more after starting charging of the battery cell, the battery cell is charged with a second charging current lower than the first charging current.SELECTED DRAWING: Figure 2

Claims

1. A charge and discharge system for performing charge and discharge of a lithium-ion secondary battery including a battery cell, a first detection unit that detects a voltage value between the first electrode serving as a positive electrode and the second electrode serving as a negative electrode of the battery cell having a first electrode serving as a positive electrode, a second electrode serving as a negative electrode, a separator disposed between the first electrode and the second electrode, and a third electrode disposed between the second electrode and the separator, a second detection unit that detects a voltage value between the first and third electrodes, and a control unit that controls charge and discharge of the battery cell, wherein the control unit starts charging of the battery cell with a predetermined first charging current, and after starting charging of the battery cell, when a difference between a second voltage value detected by the second detection unit and a first voltage value detected by the first detection unit becomes equal to or greater than a predetermined threshold value, charges the battery cell with a second charging current lower than the first charging current, a charge and discharge system.

2. a charging connector connected to a power source to supply a charging current to the lithium-ion secondary battery, and an electric motor that is driven by the lithium-ion secondary battery to serve as a power source and also serves as a generator that charges the lithium-ion secondary battery, wherein the control unit controls a regenerative torque of the electric motor so that the battery cell is charged with the first or second charging current when charging the lithium-ion secondary battery using the electric motor, The charge and discharge system according to claim 1.

3. a first limit value of the charging current is preset based on experiments, and further includes an arithmetic unit that calculates a second limit value obtained by multiplying a difference between the first and second voltage values by a predetermined coefficient to correct the first limit value, wherein the control unit charges the battery cell with the first charging current less than the first limit value when the difference between the first and second voltage values is less than the predetermined threshold value, and charges the battery cell with the second charging current less than the second limit value when the difference between the first and second voltage values is equal to or greater than the predetermined threshold value, The charge and discharge system according to claim 1.

4. A charge and discharge system for performing charge and discharge of a lithium-ion secondary battery including a battery cell, a first detection unit that detects a voltage value between the first and second electrodes of the battery cell having a first electrode serving as a positive electrode, a second electrode serving as a negative electrode, a separator disposed between the first electrode and the second electrode, and a third electrode disposed between the second electrode and the separator; a second detection unit that detects a voltage value between the first and third electrodes; a control unit that adjusts a charging current of the battery cell based on a difference between a second voltage value detected by the second detection unit and a first voltage value detected by the first detection unit; and the control unit during charging of the battery cell, when the difference between the first and second voltage values increases, decreases the charging current, and when the difference between the first and second voltage values decreases, increases the charging current; a charge-discharge system.

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