Deviation detection method and deviation detection device

1. A deviation detection method, wherein

it is used to detect positional deviation of an electrode assembly during winding, the electrode assembly comprising a first electrode sheet, a second electrode sheet and a separator,

the deviation detection method includes:

obtaining a first image and a second image using a first camera and a second camera, the first image comprises an image of a first electrode sheet of an electrode assembly during winding, and the second image comprises an image of a second electrode sheet of the electrode assembly during winding;

determining camera deviation, comprising determining whether the first camera and/or the second camera is deviated according to a distance from a reference point in the first image to a specific position and/or a distance from a reference point in the second image to the specific position, the specific position being a position of a same object appearing in the first image and the second image; and

determining electrode assembly deviation, comprising determining whether the electrode assembly is deviated according to a vertical distance from the reference point in the first image to a boundary of the first electrode sheet and a vertical distance from the reference point in the second image to a boundary of the second electrode sheet in response to determining that the first camera and the second camera are not deviated.

2. The deviation detection method according to claim 1 , wherein determining the camera deviation comprises:

obtaining a first distance according to the first image, the first distance being a distance from a first reference point to the specific position;

obtaining a second distance according to the second image, the second distance being a distance from a second reference point to the specific position; and

determining that there is a relative displacement between the first camera and the second camera in response to a difference between the first distance and the second distance being greater than a threshold.

3. The deviation detection method according to claim 2 , wherein:

determining the electrode assembly deviation comprises:

obtaining a third distance according to the first image, the third distance being a vertical distance from a third reference point to the boundary of the first electrode sheet;

obtaining a fourth distance according to the second image, the fourth distance being a vertical distance from a fourth reference point to the boundary of the second electrode sheet; and

determining that the electrode assembly is deviated in response to the difference between the first distance and the second distance being less than or equal to the first threshold and a difference between the third distance and the fourth distance minus a preset distance between the boundary of the first electrode sheet and the boundary of the second electrode sheet being greater than a second threshold.

4. The deviation detection method according to claim 2 , wherein determining the electrode assembly deviation comprises:

obtaining a third distance according to the first image, the third distance being a vertical distance from a third reference point to the boundary of the first electrode sheet;

obtaining a fourth distance according to the second image, the fourth distance being a vertical distance from a fourth reference point to the boundary of the second electrode sheet; and

determining that the first electrode sheet is deviated in response to the difference between the first distance and the second distance being less than or equal to the threshold and the third distance exceeds a reference range of the third distance; and

determining that the second electrode sheet is deviated in response to the difference between the first distance and the second distance being less than or equal to the threshold and the fourth distance exceeds a reference range of the fourth distance.

5. The deviation detection method according to claim 2 , wherein: determining the electrode assembly deviation comprises:

obtaining a third distance from the first image, the third distance being a vertical distance from a third reference point to the boundary of the first electrode sheet;

obtaining a fourth distance from the second image, the fourth distance being a vertical distance from a fourth reference point to the boundary of the second electrode sheet; and

determining that the electrode assembly is deviated in response to a difference between the third distance and the fourth distance minus a preset distance between the boundary of the first electrode sheet and the boundary of the second electrode sheet and minus the difference between the first distance and the second distance being greater than a third threshold value.

6. The deviation detection method according to claim 1 , wherein determining the camera deviation comprises:

obtaining a first distance according to the first image, the first distance being a distance from a first reference point to the specific position;

obtaining a second distance according to the second image, the second distance being a distance from a second reference point to the specific position;

determining that the first camera is deviated in response to the first distance exceeding a reference range of the first distance; and

determining that the second camera is deviated in response to the second distance exceeding a reference range of the second distance.

7. The deviation detection method according to claim 1 , wherein:

the specific position is a boundary of a separator of the electrode assembly or a position where laser irradiates the electrode assembly; and

the laser is emitted by a laser generator and irradiates the electrode assembly for generating pixel boundaries in the first image and the second image.

8. The deviation detection method according to claim 1 , wherein:

the second camera uses an infrared light source to penetrate a layer of the separator and photograph the second electrode sheet behind the separator.

9. The deviation detection method according to claim 1 , wherein:

the separator comprises a first separator and a second separator;

the first image comprises the first electrode sheet and the first separator;

the second image comprises the second electrode sheet and the second separator; and

the specific position is a boundary of the second separator that is exposed from the first separator or a boundary of the first separator that is exposed from the second separator.

10. A deviation detection device, wherein

it is used to detect positional deviation of an electrode assembly during winding, the electrode assembly comprising a first electrode sheet, a second electrode sheet and a separator, and

the deviation detection device comprises:

a first camera and a second camera for obtaining a first image and a second image respectively, the first image comprising an image of a first electrode sheet of an electrode assembly during winding;

the second image comprising an image of a second electrode sheet of the electrode assembly during winding; and

a deviation determining unit configured to:

determine whether the first camera and the second camera are deviated according to a distance from a reference point in the first image to a specific position and a distance from a reference point in the second image to the specific position; and

determine whether the electrode assembly is deviated according to a vertical distance from the reference point in the first image to a boundary of the first electrode sheet and a vertical distance from the reference point in the second image to a boundary of the second electrode sheet in response to determining that the first camera and the second camera are not deviated.