KR102450314B1 - Printed Circuit Board And Manufacturing Method Thereof - Google Patents

Abstract

A printed circuit board for battery voltage sensing of the present invention includes: a body portion formed in an extension direction of the battery cell; a connection part extending from the body part and disposed on both sides of each of the battery cells; and a junction formed at an end of the connection part and joined to a bus bar to be electrically connected to each of the battery cells, wherein the junction part is formed by folding the exposed part formed by exposing the internal circuit layer of the connection part This enables laser direct welding while improving product reliability by improving defects.

Description

Printed Circuit Board And Manufacturing Method Thereof

The present invention relates to a printed circuit board and a method for manufacturing the same, and more particularly, to a printed circuit board for sensing the voltage of a battery pack that supplies power to a plurality of electric devices of a vehicle, and a method for manufacturing the same.

Secondary batteries are widely used in mobile devices, auxiliary power devices, and the like. In addition, secondary batteries are attracting attention as a main power source for electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, etc., which are suggested as an alternative to solve various problems such as air pollution of conventional gasoline and diesel vehicles.

Secondary batteries used in electric vehicles and the like use battery packs in which a plurality of battery cells are stacked and electrically connected in series and in parallel due to the need for high-output, large-capacity batteries. Such a battery pack has the advantage of providing a high output required according to the degree of stacking of the battery cells, but phenomena such as overvoltage, overcurrent, and overheating may occur in some battery cells by stacking a plurality of battery cells.

Since this phenomenon affects the stability or operating efficiency of the battery pack, a means for detecting it in advance is required. Therefore, the battery pack senses the voltage of each battery cell using a printed circuit board connected to the battery cell, and transmits the information to the BMS (Battery Management System) through the bus bar to prevent overvoltage, overcurrent, and overheating of the battery cells. Detect phenomena and prevent further damage accordingly.

At this time, in the conventional printed circuit board, the cost was reduced by thinning the copper foil forming the internal circuit layer, and the process was simplified by removing the insulating layer at the distal end to form a junction directly bonded to the bus bar.

However, since the joint part is also formed of thin copper foil, the defect rate during laser welding is high, so there is a problem in that the productivity of the product is rapidly reduced.

In addition, as the junction is formed by stripping the insulating layer, a void is generated between the bus bar and the junction during laser welding, increasing productivity and reliability degradation.

The embodiment of the present invention has been devised to solve the above problems, and at the same time, a printed circuit board having improved product productivity and reliability by significantly reducing the defect rate generated during laser welding without increasing the cost, and a method for manufacturing the same intended to provide

A printed circuit board for voltage sensing of a battery pack formed by stacking a plurality of battery cells according to an embodiment of the present invention includes a body portion formed in an extension direction of the battery cells; a connection part extending from the body part and disposed on both sides of each of the battery cells; and a junction formed at an end of the connection part and joined to a bus bar to be electrically connected to each of the battery cells, wherein the junction part is formed by folding the exposed part formed by exposing the internal circuit layer of the connection part do.

Preferably, the exposed portion is recessed to be folded at a predetermined position to form a folding line, and the bonding portion is preferably joined such that a surface including an end of the exposed portion is in contact with the bus bar.

The bonding portion may be recessed from one side to form a welding portion guiding the bonding position.

In the method of manufacturing a printed circuit board for voltage sensing of a battery pack formed by stacking a plurality of battery cells according to an embodiment of the present invention, the exposed part is formed by exposing the internal circuit layer at the ends of the connection part disposed on both sides of the battery cell. exposing part forming step; a bending step of folding the exposed portion to form a bending portion; and a bonding portion forming step of forming a bonding portion thicker than the internal circuit layer by closely contacting the folded exposed portion.

After the forming of the exposed portion, a folding line forming step of forming a folding line by pressing one side of the exposed portion may be further included, and the bending step may further include forming the bending portion around the folding line.

The bonding portion forming step may include a rolling preparation step of pressing both sides of the bending portion with a press jig; before the bonding portion forming step, the folded exposed portion may be inserted into close contact with a roller.

After the joint forming step, a welding part forming step of forming a welded part by pressing from one side so that a predetermined area of the joint part is concave indentation; may further include.

Before the bending step, a grip step of fixing the distal end of the exposed portion with a bending jig; in this case, the bending step may further include rotating the bending jig around the fixed exposed portion to form the bending portion. .

As described above, according to the problem solving means of the present invention, various effects including all of the following items can be expected. However, the present invention is not established only when exhibiting all of the following effects.

The printed circuit board and the method for manufacturing the same according to the present invention form a junction by folding the exposed portion where the internal circuit layer is exposed, thereby enabling laser welding of the junction directly to the bus bar, thereby reducing the time required for the production process.

In addition, it improves the productivity of the product by minimizing damage to the joint that may occur during welding, and prevents the joint from separating due to vibrations caused by vehicle operation by providing a tensile force greater than a pre-designed predetermined level to improve product reliability and vehicle stability. improve

In addition, the thickness of the joint is increased to remove the gap between the joint and the bus bar, thereby maximizing the effect of improving welding performance and product quality.

1 is a perspective view and a side view of a state in which a conventional printed circuit board is attached to a bus bar;
2 is a plan view of a printed circuit board according to an embodiment of the present invention.
Figure 3 is a perspective view of the connection portion of Figure 2;
4 is a perspective view of a portion A of the connection part of FIG. 3 and a cross-sectional view taken in the IV-IV direction;
5 is a perspective view and a cross-sectional view in the V-V direction of another embodiment of a portion A of the connection part of FIG. 3 .
Figure 6 is a perspective view of the exposed portion before forming the joint of Figure 4;
7 is a cross-sectional view taken in a direction VII-VII of FIG. 6 ;
8 is a perspective view of a state in which a joint is joined to a bus bar;
9 is a cross-sectional view taken in the IX-IX direction of FIG. 8;
10 is a flowchart of a method of manufacturing a printed circuit board according to an embodiment of the present invention.
11 is a view showing the manufacturing method of FIG. 10 in one side view;

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

Although the printed circuit board and the method for manufacturing the printed circuit board of the present invention are each described, the purpose and effect thereof are the same. Therefore, the same points are described in the printed circuit board, and the same reference numerals are used for the same components.

In addition, for convenience of description, the extension direction (X) is defined as a direction in which the battery cells extend, and the stacking direction (Y) is defined as a direction in which a plurality of battery cells are sequentially arranged.

2 is a plan view of a printed circuit board according to an embodiment of the present invention, FIG. 3 is a perspective view of the connection part of FIG. 2 , and FIG. 4 is a perspective view of a part A of the connection part of FIG. 3 and a cross-sectional view in the IV-IV direction, and FIG. 5 is a perspective view and a cross-sectional view in the V-V direction of another embodiment of the connection part A of FIG. 3 . 6 is a perspective view of the exposed part before forming the joint of FIG. 4 , FIG. 7 is a cross-sectional view in the VII-VII direction of FIG. 6 , FIG. 8 is a perspective view of the state in which the joint is joined to the bus bar, and FIG. 9 is IX- of FIG. It is a cross-sectional view in the IX direction.

2 to 9 , the printed circuit board 100 for voltage sensing of a battery pack formed by stacking a plurality of battery cells includes a body 110 formed in the extending direction X of the battery cells, the A connector 120 extending from the body 110 and disposed on both sides of each battery cell and formed at an end of the connector 120, joined to the bus bar 5 and electrically connected to each battery cell It includes a junction part 130, and the junction part 130 is characterized in that the exposed part 131 formed by exposing the internal circuit layer 102 of the connection part 120 is folded and formed.

The battery pack is formed by stacking a plurality of battery cells that are secondary batteries, and the stacked plurality of battery cells are connected in series or parallel to each other to provide a high voltage to an electric vehicle or the like.

At this time, as a high voltage is generated as a plurality of battery cells are electrically connected to the battery pack, phenomena such as overvoltage and overcurrent may occur in some battery cells, and these phenomena affect the stability and operating efficiency of the battery pack. The battery pack includes a circuit board for sensing the voltage of each battery cell. Here, the circuit board may have various shapes, but is preferably formed of the printed circuit board 100 in order to save weight and space.

The printed circuit board 100 is formed by stacking insulating layers 101 on both sides of the metal circuit layer 102 constituting the internal circuit, wherein the circuit layer 102 is a copper foil layer 102 with high electrical conductivity. It is preferably formed of

Hereinafter, the shape of the printed circuit board 100 is divided into a body part 110 , a connection part 120 , and a bonding part 130 for convenience of explanation. Therefore, in each part constituting the printed circuit board 100, the insulating layer 101, the circuit layer 102, and the insulating layer 101 are sequentially laminated and formed, and the circuit layer 102 penetrates through each component. formed and electrically connected to the bus bar 5 to constitute a plurality of closed circuits.

The body part 110 is formed in a band shape in the extending direction (X) of the battery cell so as to be disposed on both electrodes of the battery cell of the connection part 120 , and the connection part 120 is formed on both sides of the body part 110 . is formed, and the plurality of battery cells and the junction part 130 extend in the stacking direction Y of the battery cells to more easily electrically connect the battery cells.

Accordingly, a plurality of junctions 130 are formed at the distal end of the connection part 120 in the stacking direction Y, and are electrically connected to each battery cell.

In order to electrically connect the internal circuit layer 102 of the connection part 120 and the bus bar 5 to the bus bar 5 without a separate member, the junction 130 is an exposed exposed portion of the internal circuit layer 102 formed at the end of the connection part 120 . The portion 131 is formed by folding.

Specifically, the bonding portion 130 is formed to have a thicker thickness by folding the exposed portion 131 in which the end internal circuit layer 102 of the connecting portion 120 is exposed, and at this time, the exposed portion 131 at an easier and more accurate position. A folding line 132 is formed by being recessed into one side of the exposed portion 131 in order to fold the .

The folding line 132 is recessed at one side of the exposed portion 131 to reduce the stress required for folding, and to allow the exposed portion 131 to be folded at a pre-designed position, but occurs on the folding line 132 . It is preferable to form a concave shape of the cross-section in order to alleviate the stress concentration phenomenon.

Accordingly, when the exposed portion 131 is folded, a curved bending portion 133 is formed on the other side of the exposed portion 131 centered on the folding line 132 to minimize damage that may occur during the folding process and workability. has the effect of improving

In addition, the bonding portion 130 is formed by the thickness of the insulating layer 101 on one side of the connection portion 120 as one side of the exposed portion 131 formed on both sides around the folding line 132 is in close contact with each other. It is formed to offset the gap, so that no voids are generated when the bus bar 5 and the joint part 130 are joined, thereby improving the welding quality, thereby maximizing the effect of improving the productivity and reliability of the product.

Therefore, it is preferable that the junction part 130 is joined to one side of the exposed part 131 and the bus bar 5 .

The bonding portion 130 of another embodiment is formed in the same manner as the above-described bonding portion 130 , but after the exposed portion 131 is folded to form the bonding portion 130 , the outside of the bonding portion 130 , that is, the inside of the connection portion 120 . A welding part 134 is further formed by recessing in the surface connected to the circuit layer 102 .

The welding part 134 is recessed from the outside of the junction part 130 to protrude a predetermined distance to the inside where the end of the exposed part 131 is formed to guide the welding position of the junction part 130 and at the same time, the junction part 130 and the bus bar ( 5) to increase the effect of improving the welding performance by making it closer to each other.

However, since an additional process is required to form the welding part 134 , it is possible to select whether to form the welding part 134 in consideration of the cost and accompanying effects of the increase in the process.

Therefore, in the printed circuit board 100 of the present invention, the thickness of the junction portion 130 to be bonded to the bus bar 5 is increased, so that the bus bar 5 and the junction portion 130 can be directly laser-welded and bonded. Damage such as bursting of the starting copper foil does not occur, so the productivity of the product is improved, and at the same time, the bonding force is increased to prevent the bonding part 130 from being arbitrarily separated from the bus bar 5 even in continuous vibration caused by vehicle operation, thereby significantly improving product reliability. improve

In addition, the gap between the bus bar 5 and the junction 130 due to the insulating layer 101 can be canceled by not increasing the thickness of the junction 130 equally, but by folding and increasing the exposed part 131 to one side. At the same time, since the internal circuit layer 102 can be kept thin, the cost and weight are not increased, so the utilization is very high.

In other words, in the printed circuit board 100 of the present invention, the internal circuit layer 102 can be kept thin and only the thickness of the junction 130 is increased to enable direct laser welding with the bus bar 5 to improve workability, By folding the exposed part 131 to one side, the welding performance and quality are remarkably improved by removing the void with the bus bar 5 .

Hereinafter, a manufacturing method of forming the bonding portion 130 by folding the exposed portion 131 will be described in detail.

10 is a flowchart of a method of manufacturing a printed circuit board according to an embodiment of the present invention, and FIG. 11 is a view showing the manufacturing method of FIG. 10 in a side view.

10 and 11 , in the manufacturing method of the printed circuit board 100 for voltage sensing of a battery pack, which is formed by stacking a plurality of battery cells, at the end of the connection part 120 disposed on both sides of the battery cell. The exposed portion forming step (S10) of exposing the internal circuit layer 102 to form the exposed portion 131, the bending step of forming the bending portion 133 by folding the exposed portion 131 (S50) and the folded and a bonding portion forming step (S70) of forming the bonding portion 130 thicker than the internal circuit layer 102 by making the exposed portion 131 in close contact.

At this time, after the exposing part forming step (S10), the folding line forming step (S20) of forming the folding line 132 by pressing one side of the exposed part 131, before the junction forming step (S70), the bending After the rolling preparation step of first pressing both sides of the portion 133 with a press jig, and the bonding portion forming step (S70), the welding portion 134 is formed by pressing from one side so that a certain area of the bonding portion 130 is indented. Before forming the welding part forming step (S80) and the bending step (S50) to form, it is preferable to further include a grip step (S40) of fixing the distal end of the exposed part 131 with a bending grip (G).

The exposed part forming step ( S10 ) is a step of removing the insulating layer 101 from the end of the connecting part 120 to form the exposed part 131 , specifically, the connection position between the bus bar 5 and the junction part 130 . The exposed portion 131 is formed by later removing the insulating layers 101 on both sides of the internal circuit layer 102 formed in the (131) can be formed.

In other words, the exposed part 131 is formed to extend from the internal circuit layer 102 of the connection part 120 , thereby separately for electrical connection between the internal circuit layer 102 of the printed circuit board 100 and the bus bar 5 . It simplifies the manufacturing process by not using the member of

The folding line forming step (S20) is a step of forming a recessed folding line 132 by pressing one side of the exposed portion 131, and guides the bending position of the exposed portion 131 to provide a more accurate position for the bonding portion 130. to be formed. Specifically, after the exposed portion 131 is formed, the first press jig P1 is positioned at a predetermined position on the exposed portion 131 and then pressed with a predetermined or higher pressure to cross the exposed portion 131 and form thinner than other portions. to form a groove

Afterwards, the folding line 132 becomes the portion where the exposed portion 131 is folded, so that the cross section of the stress concentration can be alleviated to minimize damage such as tearing of the thin internal circuit layer 102 during folding. It is preferable to be concavely formed.

Preferably, the folding line 132 is formed so as to be biased to the outside by a predetermined distance from the midpoint of the exposed portion 131, so that when the bonding portion 130 is formed, it is in close contact with a certain area of one surface of the exposed portion 131 or more, the exposed portion It is preferable that the distal end of 131 is not disposed outside the insulating layer 101 of the connecting portion 120 .

The fixing step ( S30 ) is a step of preparing the bending step ( S50 ), and by fixing one side of the exposed part 131 , the folding of the exposed part 131 is made easier. Specifically, the exposed part 131 formed on the inside with respect to the folding line 132 is fixed, and the exposed part 131 moves while the exposed part 131 formed on the outside with respect to the folding line 132 is rotated. Fix it so it doesn't stick.

In addition, after the fixing step (S30), a gripping step (S40) of fixing the distal end of the exposed part 131 with a bending grip (G) proceeds. In the grip step (S40), in a state in which the exposed portion 131 formed on the inside of the folding line 132 is fixed, hold the exposed portion 131 formed on the outside of the folding line 132 to prepare for the bending step (S50). do.

The bending step S50 is a step of forming the bending portion 133 on one side of the exposed portion 131 by folding the exposed portion 131 . At this time, the bending step (S50) is possible by the operator or the bending grip (G), hereinafter, a method of bending through the bending grip (G) will be described.

Specifically, in the bending step (S50), in a state in which the bending grip (G) holds the end of the exposed portion 131 and is fixed, the bending grip (G) is used as an axis of the fixed exposed portion 131 as the inner side of the exposed portion 131 . One side of the exposed portion 131 is rotated to face the folding line 132 as the center. Accordingly, the bending portion 133 is formed outside the folding line 132 .

Therefore, in the method of manufacturing the printed circuit board 100 of the present invention, the exposed portion 131 extending from the inner circuit layer 102 of the connecting portion 120 is formed and directly electrically connected to the bus bar 5 without a separate relay member. By increasing only the thickness of the bonding portion 130 that is folded and joined to the bus bar 5, laser welding is possible, and at the same time, damage that may occur during laser welding is minimized, thereby remarkably improving product productivity and reliability.

The rolling preparation step (S60) is a step of preparing the joint forming step (S70) by first pressing the bending part 133 with the second press jig P2, and in the joint forming step (S70), the bending part 133 is The junction part 130 can be formed at a designed position by constant pressure, and the pressure applied to the bending part 133 sequentially reduces damage to the bending part 133 .

The bonding portion forming step (S70) is a step of forming the bonding portion 130 that is connected to the internal circuit layer 102 of the connection portion 120 by closely contacting the folded exposed portion 131, and is thicker than the internal circuit layer 102 (S). ), in the printed circuit board 100 of one embodiment, by folding the exposed part 131 while maintaining the cost and weight of the printed circuit board 100 below a certain level by having the internal circuit layer 102 of 1 OZ. The junction 130 of the copper foil layer 102 of OZ is formed to enable laser welding.

Specifically, the joint forming step (S70) may be performed in various ways in which one surface is in close contact with each other by applying pressure to the folded exposed part 131, but the joint forming step (S70) of an embodiment is a second press jig (P2). ) by inserting the exposed portion 131 pressed primarily between the bending portion 133 and the roller R to form the bonding portion 130 .

In this way, when the bonding portion 130 is formed using the roller R, the same pressure is generated over the entire area of the bonding portion 130 to minimize the occurrence of voids between one side of the exposed portion 131 that is in close contact. , thereby increasing the effect of improving laser welding performance and quality.

In addition, in the method for manufacturing the printed circuit board 100 of the present invention, after the bonding portion forming step (S70), the welding portion 134 is formed by pressing to indent a predetermined area from the outside of the bonding portion 130 to the third press jig P3. A welding part forming step (S80) may be further included. Specifically, the welding part 134 presses the junction part 130 in the inner direction of the junction part 130 in contact with the bus bar 5 from the outside of the junction part 130 disposed outward when joining the bus bar 5 . It is defined as a recessed groove formed.

Accordingly, the bonding position can be more accurately identified when the bonding portion 130 and the bus bar 5 are bonded, so that the insulating layer 101 disposed on the outside of the connection portion 120 has a surface protruding a predetermined distance in the inward direction. The void generated between the bus bar 5 and the bonding portion 130 during bonding is offset to improve laser welding performance.

However, the welding part forming step (S80) is to be additionally performed after the joint forming step (S70), and may be omitted for simplification of the process.

Therefore, the printed circuit board 100 manufacturing method of the present invention directly bonds the bonding portion 130 to the bus bar 5 with a laser to simplify the process and at the same time improve workability to provide more improved product productivity, and to improve welding quality. It improves the productivity of the product by improving the product, and by ensuring the tensile force above a certain level required for the product, it prevents the junction 130 from being arbitrarily separated even in repeated vibrations caused by vehicle operation, thereby improving the reliability of the product and the safety of the occupants. have

Although preferred embodiments of the present invention have been exemplarily described above, the scope of the present invention is not limited to such specific embodiments, and it is within the protection scope of the present invention that can be appropriately changed within the scope described in the claims. corresponds to

Although preferred embodiments of the present invention have been exemplarily described above, the scope of the present invention is not limited to such specific embodiments, and it is within the protection scope of the present invention that can be appropriately changed within the scope described in the claims. corresponds to

100 Printed circuit board 101 Insulation layer 102 Circuit layer (copper foil)
110 body part 120 connection part
130 Joint 131 Exposed 132 Folding Line
133 Bending part 134 Welding part
P1 1st press jig P2 2nd press jig P3 3rd press jig
G Bending Grip R Roller

Claims (10)

In the printed circuit board for voltage sensing of a battery pack formed by stacking a plurality of battery cells,
a body portion formed in an extension direction of the battery cell;
a connection part extending from the body part and disposed on both sides of each of the battery cells; and
A junction part formed by exposing an internal circuit layer at an end of the connection part is folded along a recessed folding line, and joined to a bus bar to be electrically connected to each of the battery cells;
the junction
A printed circuit board, characterized in that a welding portion is formed inwardly from one side of the exposed portion connected to the connection portion to guide a bonding position, and the other side of the exposed portion is bonded to the bus bar.
delete delete delete In the manufacturing method of a printed circuit board for voltage sensing of a battery pack formed by stacking a plurality of battery cells,
an exposed part forming step of exposing an internal circuit layer at the ends of the connection part disposed on both sides of the battery cell to form the exposed part;
a folding line forming step of forming a folding line by pressing one side of the exposed part;
a bending step of forming a bending part by folding the exposed part around the folding line;
a rolling preparation step of first pressing both sides of the bending part with a press jig;
a bonding portion forming step of forming a bonding portion thicker than the internal circuit layer by closely contacting the folded exposed portion with a roller; and
and a welding part forming step of forming a welding part by pressing from one side so that a predetermined area of the joint part is concave.
delete delete delete delete 6. The method of claim 5,
Before the bending step, a grip step of fixing the distal end of the exposed part with a bending jig; further comprising,
The banding step is
The method of manufacturing a printed circuit board, characterized in that the bending part is formed by rotating the bending jig around the fixed exposed part.

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