Battery pack

1 . A battery pack, comprising:

at least one battery cell;

a protection circuit module electrically connected to the at least one battery cell; and

a thermocompression bonding layer, the thermocompression bonding layer providing a disconnectable electrical connection between an electrode tab of the at least one battery cell and a connection tab of the protection circuit module,

wherein:

the thermocompression bonding layer includes conductive particles and an insulating composite resin layer,

the insulating composite resin layer surrounds the conductive particles,

the insulating composite resin layer includes at least one first resin layer and at least one second resin layer, the at least one first resin layer being different from the at least one second resin layer and

the insulating composite resin layer is between the electrode tab of the at least one battery cell and the connection tab of the protection circuit module.

2 . The battery pack as claimed in claim 1 , wherein

the at least one first resin layer includes a thermoplastic resin material that undergoes a volume expansion at a temperature greater than or equal to a predetermined transition temperature, and

the at least one second resin layer includes a thermosetting resin material that maintains shape stability at a temperature greater than or equal to the predetermined transition temperature.

3 . The battery pack as claimed in claim 2 , wherein the predetermined transition temperature is a predetermined threshold temperature for detecting an abnormal situation of the at least one battery cell.

4 . The battery pack as claimed in claim 1 , wherein the at least one first resin layer and the at least one second resin layer are stacked with respect to each other between the electrode tab of the at least one battery cell and the connection tab of the protection circuit module.

5 . The battery pack as claimed in claim 4 , wherein the at least one first resin layer and the at least one second resin layer are different layers separated from each other with an interface therebetween.

6 . The battery pack as claimed in claim 1 , wherein the insulating composite resin layer is between the electrode tab of the at least one battery cell and the connection tab of the protection circuit module in a two-layer structure including the at least one first resin layer and the at least one second resin layer stacked with respect to each other.

7 . The battery pack as claimed in claim 6 , wherein a thickness of the at least one first resin layer is about equal to a thickness of the at least one second resin layer.

8 . The battery pack as claimed in claim 1 , wherein:

the at least one first resin layer includes two separate first resin layers, and

the insulating composite resin layer is between the electrode tab of the at least one battery cell and the connection tab of the protection circuit module in a three-layer structure in which the at least one second resin layer is between the separate first resin layers.

9 . The battery pack as claimed in claim 8 , wherein the two separate first resin layers are adjacent to:

a position at which the electrode tab and the conductive particles contact each other, and

a position at which the connection tab and the conductive particles contact each other.

10 . The battery pack as claimed in claim 8 , wherein:

the two separate first resin layers include an upper first resin layer and a lower first resin layer,

the at least one second resin layer is between the upper first resin layer and the lower first resin layer,

a thickness of the upper first resin layer is about the same as a thickness of the at least one second resin layer, and

the thickness of the upper first resin layer is about the same as a thickness of the lower first resin layer.

11 . The battery pack as claimed in claim 1 , wherein:

the at least one second resin layer includes two separate second resin layers, and

the insulating composite resin layer is between the electrode tab of the at least one battery cell and the connection tab of the protection circuit module in a three-layer structure in which the at least one first resin layer is between the separate second resin layers.

12 . The battery pack as claimed in claim 11 , wherein:

the two separate second resin layers include an upper second resin layer and a lower second resin layer,

the at least one first resin layer is between the upper second resin layer and the lower second resin layer,

a thickness of the upper second resin layer is about the same as a thickness of the at least one first resin layer, and

the thickness of the upper second resin layer is about the same as a thickness of the lower second resin layer.

13 . The battery pack as claimed in claim 1 , wherein the thermocompression bonding layer provides a high-current path for a charging/discharging current of the at least one battery cell.

14 . The battery pack as claimed in claim 1 , wherein the at least one battery cell includes a plurality of different battery cells that are electrically connected with the protection circuit module.

15 . The battery pack as claimed in claim 14 , wherein the plurality of different battery cells are adjacent to each other such that electrode tabs connected to the protection circuit module extend in parallel with each other.

16 . The battery pack as claimed in claim 15 , wherein the protection circuit module includes an avoidance hole at a position between the plurality of different battery cells adjacent to each other, the avoidance hole accommodating sealing parts of the different battery cells.

17 . The battery pack as claimed in claim 1 , wherein:

the at least one battery cell includes a first electrode tab and a second electrode tab having different polarities,

the protection circuit module includes a first connection tab connected to the first electrode tab and a second connection tab connected to the second electrode tab, respectively, and

the thermocompression bonding layer is between the first electrode tab and the first connection tab and between the second electrode tab and the second connection tab.