Eddy current sensor for detecting crack of battery cell and system for detecting crack of battery including the same
The present invention relates to an eddy current sensor for detecting a crack in a battery cell, and a system for detecting a crack of a battery cell including the eddy current sensor. According to the present invention, it is possible to easily detect a crack generated in an electrode, an electrode tab or a welded portion.
1. An eddy current sensor for detecting a crack of an inside of a battery cell, the eddy current sensor comprising:
a probe;
a transmission unit which is arranged on a probe and has a structure on which a transmitting coil, which induces an eddy current to the battery cell, is wound; and
a receiving unit which is arranged on the probe and is arranged in a region spaced apart from the transmission unit, and has a structure on which a receiving coil, which senses a signal change by the eddy current induced to the battery cell by the transmitting coil, is wound,
wherein a cross-sectional area S 1 of the transmission unit, on which the transmitting coil has been wound, is greater than a cross-sectional area R 1 of the receiving unit on which the receiving coil has been wound, and
a ratio (S 1 :R 1 ) of the cross-sectional area S 1 of the transmission unit to the cross-sectional area R 1 of the receiving unit is in a range of 1.5:1 to 10:1, and
the transmission unit and the receiving unit are spaced apart from each other at an interval of 1 to 50 mm.
2. The eddy current sensor of claim 1 , wherein a ratio (S 1 :R 1 ) of the cross-sectional area S 1 of the transmission unit to the cross-sectional area R 1 of the receiving unit is in a range of 1.5:1 to 3:1.
3. The eddy current sensor of claim 1 , wherein a ratio (S 2 :R 2 ) of a width S 2 of the transmission unit to a width R 2 of the receiving unit is in a range of 1.5:1 to 10:1.
4. The eddy current sensor of claim 1 , wherein a width S 2 of the transmission unit is in a range of 1 to 100 mm and corresponds to a length L of a battery cell evaluation region.
5. The eddy current sensor of claim 1 , wherein a width S 2 of the receiving unit is in a range of 0.5 to 70 mm.
6. The eddy current sensor of claim 1 , wherein the transmission unit and the receiving unit have a winding groove in a region on which each of the transmitting coil and the receiving coil are wound.
7. The eddy current sensor of claim 1 , wherein a diameter of the transmitting coil and the receiving coil is in a range of 0.02 to 10 mm.
8. A system for detecting a crack of a battery cell, comprising:
the eddy current sensor according to claim 1 ;
a signal-receiving unit which receives a signal measured in the eddy current sensor; and
a data processing unit which determines whether there is a crack in a target battery cell, based on an amplitude and phase difference distribution of a signal received in the signal-receiving unit.
9. The system of claim 8 , further comprising: an output unit which outputs a result value determined in the data processing unit and a storage unit which stores the result value.
10. The eddy current sensor of claim 1 , wherein a ratio (S 2 :R 2 ) of a width S 2 of the transmission unit to a width R 2 of the receiving unit is in a range of 1.9:1 to 6:1.
11. The eddy current sensor of claim 1 , wherein a ratio (S 2 :R 2 ) of a width S 2 of the transmission unit to a width R 2 of the receiving unit is in a range of 2:1 to 4:1.
12. The eddy current sensor of claim 1 , wherein a ratio (S 2 :R 2 ) of a width S 2 of the transmission unit to a width R 2 of the receiving unit is in a range of 2.5:1 to 3.5:1.
13. The eddy current sensor of claim 1 , wherein the transmission unit and the receiving unit are spaced apart from each other at an interval of 3 to 40 mm.
14. The eddy current sensor of claim 1 , wherein the transmission unit and the receiving unit are spaced apart from each other at an interval of 6 to 30 mm.
15. The eddy current sensor of claim 1 , wherein the transmission unit and the receiving unit are spaced apart from each other at an interval of 8 to 20 mm.