Leak inspection apparatus and method for secondary battery cell
A leak inspection apparatus for secondary battery cells and a leak inspection method for secondary battery cells are to determine whether leakage occurs in a secondary battery cell being inspected by creating a pressure difference between the inside of a casing of the secondary battery cell accommodated in a chamber part and the internal space of the chamber part and detecting swelling of the secondary battery cell.
1 . A leak inspection apparatus for secondary battery cells, the leak inspection apparatus comprising:
a chamber part configured to define an internal space;
a first plate disposed in the internal space of the chamber part and configured to support a first side of a secondary battery cell;
a second plate configured to press a second side of the secondary battery cell opposite to the first side of the secondary battery cell;
a pressure distribution detection part configured to be disposed between the second plate and the secondary battery cell, the pressure distribution detection part including a plurality of sensor nodes distributed such that the plurality of sensor nodes are configured to cover an entire area of the second side of the secondary battery cell, the plurality of sensor nodes being configured to detect pressure of the secondary battery cell;
a vacuum part configured to communicate with the internal space of the chamber part to form a vacuum in the internal space of the chamber part; and
a controller communicatively coupled to the pressure distribution detection part and configured to determine whether a leak occurs in the secondary battery cell.
2 . The leak inspection apparatus of claim 1 , wherein the chamber part comprises:
a moving part on which the first plate is seated on a side thereof; and
a cover part configured to form the internal space of the chamber part together with the moving part.
3 . The leak inspection apparatus of claim 1 , wherein the pressure distribution detection part is a film-type pressure measurement distribution sensor.
4 . The leak inspection apparatus of claim 3 , wherein the pressure distribution detection part includes sensor nodes and transmits a pressure value measured by each sensor node to the controller.
5 . The leak inspection apparatus of claim 1 , further comprising:
a buffer member between the pressure distribution detection part and the second plate or on a surface of the second plate facing the secondary battery cell,
wherein the buffer member contains silicone material.
6 . The leak inspection apparatus of claim 1 , wherein the vacuum part comprises:
a first pipe communicating with the internal space of the chamber part;
a first valve between the first pipe and a second pipe;
the second pipe with a first end thereof is connected to the first valve, and a second end thereof is connected to a vacuum pump; and
the vacuum pump that creates vacuum in the internal space of the chamber part.
7 . The leak inspection apparatus of claim 6 , wherein the vacuum pump operates during a leak inspection of the secondary battery cell.
8 . The leak inspection apparatus of claim 1 , further comprising:
a vacuum breaking part that supplies gas, after an inspection of the secondary battery cell is completed, to the internal space of the chamber part where the internal space is vacuum formed.
9 . The leak inspection apparatus of claim 8 , wherein the vacuum breaking part is configured to supply an inert gas to the internal space of the chamber part.
10 . The leak inspection apparatus of claim 4 , wherein the controller comprises:
an initial pressure value measurement module configured to receive the initial pressure values measured by the plurality of sensor nodes before the internal space of the chamber part is vacuum formed in a state where the chamber part is sealed; and
an inspection pressure value measurement module configured to receive the inspection pressure values of the plurality of sensor nodes after the internal space of the chamber part is vacuum formed.
11 . The leak inspection apparatus of claim 10 , wherein the controller further comprises:
an initial pressure value modification module configured to zero-set the initial pressure values of the plurality of sensor nodes; and
an inspection pressure value modification module configured to calculate modified inspection pressure values for the plurality of sensor nodes by subtracting the initial pressure values from the inspection pressure values.
12 . The leak inspection apparatus of claim 11 , wherein the controller further comprises:
an average value calculation module configured to calculate an average value of the modified inspection pressure values for the sensor nodes calculated by the inspection pressure value modification module.
13 . The leak inspection apparatus of claim 10 , wherein the controller further comprises:
a change amount calculation module configured to calculate changes between the initial pressure values and the inspection pressure values for the plurality of sensor nodes, and then calculate an average value of the changes for the sensor nodes.
14 . The leak inspection apparatus of claim 13 , wherein the controller further comprises:
a good/bad determination module configured to compare the average value with a reference set value to determine whether a leak occurs in the secondary battery cell.
15 . The leak inspection apparatus of claim 1 , wherein the first plate, the second plate, and the pressure distribution detection part are provided in plurality and arranged in parallel in the internal space of the chamber part.
16 . A leak inspection method for secondary battery cells, the leak inspection method being performed using a leak inspection apparatus for secondary battery cells, the leak inspection apparatus comprising: a chamber part configured to define an internal space; a first plate disposed in the internal space of the chamber part and configured to support a first side of a secondary battery cell; a second plate configured to be spaced apart from the first plate and to press a second side of the secondary battery cell opposite to the first side of the secondary battery cell; a pressure distribution detection part configured to be disposed between the second plate and the secondary battery cell, the pressure distribution detection part including a plurality of sensor nodes distributed such that the plurality of sensor nodes are configured to cover an entire area of the second side of the secondary battery cell, the plurality of sensor nodes being configured to detect pressure of the secondary battery cell; a vacuum part configured to communicate with the internal space of the chamber part to form a vacuum in the internal space of the chamber part; a vacuum breaking part configured to supply gas, after an inspection of the secondary battery cell is completed, to the internal space of the chamber part where the internal space is vacuum formed; and a controller communicatively coupled to the pressure distribution detection part and configured to determine whether a leak occurs in the secondary battery cell, the leak inspection method comprising:
sealing the chamber part after the secondary battery cell is seated on the first plate;
measuring, by the plurality of sensor nodes, initial pressure values at the entire area of the second side of the secondary battery cell before the vacuum is formed in the internal space of the chamber part;
forming the vacuum in the internal space of the chamber part;
measuring, by the plurality of sensor nodes, inspection pressure values at the entire area of the second side of the secondary battery cell after the vacuum is formed in the internal space of the chamber part;
comparing the initial pressure values with the inspection pressure values; and
determining whether a leak occurs in the secondary battery cell based on a comparison between the initial pressure values and the inspection pressure values.
17 . The leak inspection method of claim 16 , wherein the comparing comprises:
zero-setting the initial pressure values measured by plurality of sensor nodes of the pressure distribution detection part;
calculating modified inspection pressure values by subtracting the initial pressure values from the inspection pressure values of the plurality of sensor nodes; and
deriving an average value of the modified inspection pressure values of the plurality of sensor nodes.
18 . The leak inspection method of claim 16 , wherein the comparing comprises:
calculating changes between the initial pressure values and the inspection pressure values for the plurality of sensor nodes of the pressure distribution detection part; and
calculating an average value of the changes for the plurality of sensor nodes.
19 . The leak inspection method of claim 17 , wherein the determining whether a leak occurs comprises:
determining whether a leak occurs in the secondary battery cell by comparing an average value of the modified inspection pressure values with a reference set value.