Protection circuit unit and method of bonding lead portions and protection circuit unit

1 . A protection circuit module comprising:

a printed circuit board configured to be connected to a positive lead part and a negative lead part connected to a battery cell,

wherein the printed circuit board comprises:

an upper layer bonded to the positive lead part and the negative lead part so as to be electrically connected;

an intermediate layer including a first insulating layer including a material containing an epoxy resin and provided below the upper layer; and

a laser reflective layer provided between the upper layer and the first insulating layer and reflecting light from a laser, and

wherein an end of the upper layer and an end of the laser reflective layer are aligned in a cross sectional view.

2 . The protection circuit module of claim 1 , wherein the laser reflective layer has a reflectance of 95% or more of the light having a wavelength of 1000 nm to 1100 nm.

3 . The protection circuit module of claim 2 , wherein the laser reflective layer has a reflectance of 95% or more of the light having a wavelength of 1060 nm to 1080 nm.

4 . The protection circuit module of claim 2 , wherein the laser reflective layer includes silver (Ag).

5 . The protection circuit module of claim 2 , wherein the laser reflective layer is thinner than the upper layer and the intermediate layer.

6 . The protection circuit module of claim 1 , wherein the upper layer includes copper (Cu), and

wherein the first insulating layer includes a material including the epoxy resin and glass fiber.

7 . The protection circuit module of claim 6 , wherein the intermediate layer comprises:

second and third insulating layers provided below the first insulating layer;

a first metal layer provided between the first insulating layer and the second insulating layer; and

a second metal layer provided between the second insulating layer and the third insulating layer.

8 . The protection circuit module of claim 7 , wherein the second and third insulating layers include a material including an epoxy resin and glass fiber, and

wherein the first and second metal layers include copper (Cu).

9 . The protection circuit module of claim 1 , wherein an end of the intermediate layer is aligned with both the end of the upper layer and the end of the laser reflective layer in the cross sectional view.