Printed circuit board system, electrical energy storage and method for manufacturing a printed circuit board system

Description

Field of invention

[0001] The present invention relates to a printed circuit board system, an electrical energy storage device and a method for manufacturing a printed circuit board system according to the preamble of the independent claims. State of the art

[0002] DE 10 2015 221 161 A1 discloses a contact arrangement, in particular for a transmission control module.

[0003] DE 10 2015 225 369 A1 discloses a contacting device, a battery module and a method for contacting.

[0004] DE 10 2014 210 576 A1 shows a hermetically sealed electronic unit with a flexible printed circuit board.

[0005] DE 10 2010 003 927 A1 shows a control module for a motor vehicle transmission.

[0006] JP2013222480A shows a contact arrangement produced by ultrasonic welding, which is intended in particular for a read / write head of a hard disk. Disclosure of the invention

[0007] The core of the invention in the printed circuit board system, comprising a printed circuit board and a flat conductor, consists in the fact that the printed circuit board has a contact surface, wherein the flat conductor has a cover film, a base film and an intermediate conductor film, wherein the conductor film has a connection area which is arranged in a recess of the cover film and the base film. wherein the contact surface and the connection area are materially bonded together, characterized in that the contact surface (3) and the connection area (7) form a one-piece connection section (30) which is arranged in the recess (6), and the printed circuit board system (1) has several connection sections (30).

[0008] The invention is based on the fact that the contact surface and the conductive film are directly connected. This allows for a secure connection. The electrical connection between the contact surface and the conductive film can be implemented with low resistance.

[0009] Further advantageous embodiments of the present invention are the subject of the dependent claims.

[0010] According to an advantageous embodiment, the printed circuit board has an insulating layer, wherein the contact surface is arranged on the insulating layer, and in particular, wherein a bonding agent, especially an adhesive, is arranged between the insulating layer and the cover film. Advantageously, the printed circuit board and the flat conductor have an additional connection by means of the adhesive. This provides mechanical stress relief for the connection between the contact surface and the conductor film. It is advantageous if the contact surface and the connection area form a single, integral connecting section arranged in the recess, with a pore being arranged next to the connecting section.

[0011] Advantageously, the printed circuit board system has several interconnection sections, which are arranged in a circular or linear pattern. This improves the load-bearing capacity of the connection.

[0012] Furthermore, it is advantageous if the connection section is circular, particularly if the connection section has a diameter of less than 200 µm, especially between 100 and 200 µm. This allows the use of flat conductors with thinner and / or narrower conductor foils than those used in the prior art.

[0013] It is also advantageous if the printed circuit board system includes an electrical component, particularly if the electrical component is arranged on the circuit board or the flat conductor. This allows the printed circuit board system to be used both as a conductor and as an electrical component.

[0014] The core of the invention in the electrical energy storage device consists in the fact that the electrical energy storage device has a printed circuit board system as described above or according to one of the claims relating to the printed circuit board system.

[0015] The background of the invention is that the electrical energy storage device can be implemented in a compact form.

[0016] Advantageously, the electrical energy storage device has at least two electrical energy storage cells connected by means of the printed circuit board system. A further advantage is that the printed circuit board system can be used both as a cell connector and as a controller for the electrical energy storage cells.

[0017] The core of the invention in the method for manufacturing a printed circuit board system, in particular as described above or according to one of the claims relating to the printed circuit board system, comprising a printed circuit board with a contact surface and a flat conductor with a conductor foil, is that the contact surface and the conductor foil are connected by means of a pulsed laser beam.

[0018] The invention is based on the fact that less heat energy is introduced into the printed circuit board system using the pulsed laser beam. This allows welding to be performed at the laser's focus, resulting in smaller weld spots. Consequently, flat conductors with thinner and / or narrower conductor foils than those used in the prior art can be employed.

[0019] According to an advantageous embodiment, a frequency-doubling laser beam is used, in particular wherein the laser beam has a wavelength of less than 600 nm, especially 532 nm or 515 nm. This improves the absorption of the laser radiation by the conductor foil, which is made of, for example, copper or aluminum.

[0020] Advantageously, the printed circuit board system is welded under a protective gas atmosphere, especially under argon, or in air.

[0021] It is advantageous if the conductive film is pressed against the contact surface using a holding device during the connection process. This reduces the distance between the conductive film and the contact surface, ensuring that the conductive film and the contact surface are in contact.

[0022] Furthermore, it is advantageous if the conductive film melts in a connection area and a metallurgical bond is formed with the contact surface. In addition to a connection section formed by the connection area and the contact surface, a pore can form that is completely surrounded by the contact surface and / or the conductive film and / or the connection section and / or the insulating layer. Brief description of the drawings

[0023] The exemplary embodiments are shown in the drawings.

[0024] They show: Fig. 1 a top view of a printed circuit board system 1 according to the invention; Fig. 2 a sectional view of a printed circuit board 8 and a flat conductor 9, which are connected to form a printed circuit board system 1 according to the invention by means of a laser beam 21 and a holding means 20; Fig. 3 a detailed view of a first variant of a connection of the printed circuit board 8 with the flat conductor 9; Fig. 4 a detailed view of a second variant of a connection of the printed circuit board 8 with the flat conductor 9; and Fig. 5 a sectional view of the printed circuit board system 1 after the printed circuit board 8 and the flat conductor 9 have been connected.

[0025] The in Fig. 1 The illustrated printed circuit board system 1 comprises a printed circuit board 8 and a flat conductor 9. The flat conductor 9 is arranged on the printed circuit board 8.

[0026] The flat conductor 9 has a base foil 4, a conductor foil 5 and a cover foil 14.

[0027] The conductive foil 5 is arranged between the base foil 4 and the cover foil 14. The cover foil 14 is at least partially arranged between the conductive foil 5 and the printed circuit board 8.

[0028] The conductive foil 5 is at least partially enclosed by the cover foil 14 and the base foil 4. The cover foil 14 and the base foil 4 are electrically insulating. The base foil 4 has a greater thickness than the cover foil 14.

[0029] The conductive foil 5 is electrically conductive, in particular made of copper or aluminum. The conductive foil 5 is a maximum of 100 µm thick, in particular between 20 µm and 80 µm thick, preferably 35 µm or 70 µm thick.

[0030] The cover film 14 and the base film 4 of the flat conductor 9 have a recess 6. The recess 6 exposes the conductor film 5 section by section. The exposed conductor film 5 acts as a connection area 7 for the flat conductor 9 and the printed circuit board 8.

[0031] The flat conductor 9 can be implemented as a flexible printed circuit board. The flexible printed circuit board can be multilayered.

[0032] The circuit board 8 has an insulator layer 2, a conductor track 10, a contact surface 3 and a conductor layer 13.

[0033] The contact surface 3, the conductor track 10 and the conductor layer 13 are made electrically conductive, in particular from copper or aluminium.

[0034] The contact surface 3 is a maximum of 150 µm thick, in particular between 50 µm and 130 µm thick, preferably 55 µm, 90 µm, or 125 µm thick. The contact surface 3 has the same or a greater thickness than the conductive film 5. The contact surface 3 has an edge length of a maximum of 5 mm, preferably an edge length of 3 mm.

[0035] Insulator layer 2 is designed to be electrically insulating.

[0036] The insulator layer 2 is arranged between the conductor layer 13 and the conductor track 10.

[0037] The insulator layer 2 is arranged between the conductor layer 13 and the contact surface 3.

[0038] The conductor track 10 is electrically connected to the contact surface 3. The contact surface 3 is arranged on the insulator layer 2, with the contact surface 3 partially covering the insulator layer 2.

[0039] The flat conductor 9 and the circuit board 8 are connected to each other by means of the conductive foil 5 and the contact surface 3. For this purpose, the contact surface 3 and the connection area 7 overlap at least partially. The conductive foil 5 and the contact surface 3 are electrically connected to each other.

[0040] A tin layer (24, 25, 26) is arranged on the surface of the conductive foil 5 and / or the contact surface 3 and / or the conductor track 10 and / or the conductor layer 13. The tin layer (24, 25, 26) is a maximum of 10 µm thick, preferably 5 µm thick.

[0041] Fig. 2 shows the printed circuit board system 1 shortly before connecting the printed circuit board 8 to the flat conductor 9.

[0042] A connecting element 23, in particular an adhesive, is arranged between the circuit board 8 and the flat conductor 9. The connecting element 23 joins the cover film 14 and the insulating layer 2; it is arranged at a distance from the contact surface 3.

[0043] By means of the connecting element 23, the connection area 7 and the contact surface 3 are spaced apart from each other before the connecting of the printed circuit board system 1, so that a gap 22 is created between the connection area 7 and the contact surface 3.

[0044] To connect the printed circuit board system 1, a holding element 20 is pressed onto and held against the connection area 7, reducing the distance between the connection area 7 and the contact surface 3, in particular to the point where the connection area 7 and the contact surface 3 touch each other. The connection area 7 is then joined to the contact surface 3 by means of a laser beam 21, in particular by welding. This creates a metallurgical bond between the connection area 7 and the contact surface 3.

[0045] A pulsed laser beam 21 is used to connect the connection area 7 to the contact surface 3. The laser beam 21 has a wavelength between 500 nm and 600 nm, in particular 532 nm or 515 nm.

[0046] Alternatively, the contact surface 3 and the connection area 7 can be joined by means of resistance welding, in particular gap welding or step welding.

[0047] The contact surface 3 and the connection area 7 are connected to each other by means of a single connection section 30, in particular by means of a weld point, or by means of several connection sections 30. A connection section 30 is designed as a point and has a diameter of a maximum of 200 µm, in particular 100 µm to 200 µm, in particular 120 µm to 170 µm, preferably 150 µm.

[0048] Fig. 3 This shows a first variant of the connection. The connection points are arranged in a circle (30).

[0049] Fig. 4 A second variant of the connection is shown. In this variant, the connection points are arranged linearly.

[0050] According to a further embodiment, which is not shown in the figures, an additional bonding layer is arranged on the contact surface 3. The bonding layer is, for example, made of CuSn6.

[0051] Fig. 5Figure 1 shows the printed circuit board system 1 after the connection area 7 and the contact surface 3 have been joined. The connection area 7 and the contact surface 3 are metallurgically bonded to each other and fused to form a connection section 30. The connection section 30 extends through the recess 6 in the cover film 14 from a surface of the printed circuit board system 1 to the insulating layer 2. At least one pore 31 is arranged between the cover film 14 and the connection section 30.

[0052] For the purposes of this text, an electrical energy storage device is understood to be a rechargeable energy storage device, in particular comprising an electrochemical energy storage cell and / or an energy storage module, comprising at least one electrochemical energy storage cell and / or an energy storage pack, comprising at least one energy storage module. The energy storage cell can be implemented as a lithium-based battery cell, in particular a lithium-ion battery cell. Alternatively, the energy storage cell can be implemented as a lithium-polymer battery cell, a nickel-metal hydride battery cell, a lead-acid battery cell, a lithium-air battery cell, or a lithium-sulfur battery cell.

Claims

1. Printed circuit board system (1) having a printed circuit board (8) and a flat conductor (9), the printed circuit board (8) having a contact surface (3), wherein the flat conductor (9) has a cover film (14), a base film (4) and an intermediate conductor film (5), wherein the conductor film (5) has a connecting region (7) which is arranged in a recess (6) of the cover film (14) and the base film (4), wherein the contact surface (3) and the connecting region (7) are connected to one another in a materially bonded manner, characterized in that the contact surface (3) and the connecting region (7) form a one-piece connecting portion (30) which is arranged in the recess (6), and the printed circuit board system (1) comprises multiple connecting portions (30).

2. Printed circuit board system (1) according to Claim 1, characterized in that the printed circuit board (8) has an insulating layer (2), wherein the contact surface (3) is arranged on the insulating layer (2), in particular wherein a connecting means (23), in particular an adhesive, is arranged between the insulating layer (2) and the cover film (14).

3. Printed circuit board system (1) according to one of the preceding claims, characterized in that a pore (31) is arranged next to the connecting portion (30).

4. Printed circuit board system (1) according to one of the preceding claims, characterized in that the connecting portions (30) are arranged in a circular or linear manner.

5. Printed circuit board system (1) according to Claim 3 or 4, characterized in that the connecting portion (30) is circular, in particular wherein the connecting portion (30) has a diameter smaller than 200 µm, in particular between 100 and 200 µm.

6. Printed circuit board system (1) according to one of the preceding claims, characterized in that the printed circuit board system (1) has an electrical component, in particular wherein the electrical component is arranged on the printed circuit board (8) or the flat conductor (9).

7. Electrical energy storage device, characterized in that the electrical energy storage device has at least one printed circuit board system (1) according to one of Claims 1 to 6.

8. Electrical energy storage device according to Claim 7, characterized in that the electrical energy storage device has at least two electrical energy storage cells which are connected by means of the printed circuit board system (1).

9. Method for producing a printed circuit board system (1) according to one of Claims 1 to 6, characterized in that the contact surface (3) and the conductor film (5) are connected by means of a pulsed laser beam (21).

10. Method according to Claim 9, characterized in that a laser beam (21) with frequency doubling is used, in particular wherein the laser beam (21) has a wavelength of less than 600 nm, in particular of 532 nm or 515 nm.

11. Method according to Claim 9 or 10, characterized in that the conductor film (5) is pressed to the contact surface (3) by means of a holding means (20) during the connection.

12. Method according to one of Claims 9 to 11, characterized in that the conductor film (5) melts in a connecting region (7) and a materially bonded connection with the contact surface (3) is established.