JP2009259920A - Circuit board and method of producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board which makes heat not to transmit easily to solder for joining the substrate of circuit and a conductive block, when the conductive block and a tab for external connection are welded, and to provide a method of producing a circuit board. <P>SOLUTION: A conductive block 15, provided with a conductive block solder receiving portion 15b for preventing molten solder from scattering to the outside, and a conductive block protrusion 15a for connection with a conductive through-hole 12 as the electrode portion of the substrate 11 of circuit, is electrically and mechanically bonded to the substrate 11 of circuit provided with the conductive through-hole 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit board to which an external connection tab is welded, such as a protection circuit board for a battery pack, and a method for manufacturing the circuit board.

  The protection circuit board is an indispensable element for constituting the battery pack, and is used in most battery packs. The battery pack has a structure in which a protective substrate circuit and an external connection tab are joined by resistance welding, and the protective circuit substrate and the battery are electrically and mechanically connected via the external connection tab.

  In such a protection circuit board, an electrode pad is formed on one surface, a solder paste is applied to the surface of the electrode pad, a conductive block is mounted on the solder paste, and the conductive block is electrically connected via the solder. And it is the structure which joins mechanically. The external connection tab is electrically and mechanically connected by resistance welding to the surface of the conductive block joined to the protective circuit board via solder.

  FIG. 4 shows the structure of a protection circuit board according to the prior art. 4A is a plan view, and FIG. 4B is a cross-sectional view during welding. 4 (a) and 4 (b), reference numeral 41 denotes a protection circuit substrate, 42 denotes an electrode pad, 43 denotes a resist used when forming a solder layer, and 44 denotes a solder layer (composition: Su96.5%, Ag3. 0%, Cu 0.5%, melting point 200 ° C. to 240 ° C.), 45 is a conductive block mainly composed of nickel (size 3.0 mm in length, 3.0 mm in width, thickness 0.2 to 0.4 mm), 46 is an external connection tab mainly made of nickel (width 2.5 mm to 3.0 mm, thickness 0.100 mm to 0.125 mm), 47 is a welding rod used for welding the conductive block and the external connection tab, and 48 is welding. The direction of the current at the time, 49 indicates a region where heat generated by welding is transmitted, and 50 indicates scattering of remelted solder.

  In the method of manufacturing the circuit board, a resist 43 is applied to the protection circuit board 41 to form the solder layer 44, and then the solder layer 44 is formed. A conductive block 45 is set on the solder layer 44, and the conductive block 45 is solder-welded to the substrate 41 of the protection circuit by heating. An external connection tab 46 is set on the conductive block 45, and the conductive block 45 and the external connection tab 46 are welded using a welding rod 47.

  The electrical connection between the electrode pad 42 and the external connection tab 46 can be made more reliable by connecting with the circuit board manufacturing method described above, but the problem here is the resistance The heat generated when welding the external connection tab 46 by welding is transmitted to the back surface of the conductive block 45. Due to the heat transferred to the back surface, the temperature becomes higher than the melting point of the solder, and the solder layer 44 directly formed on the back surface of the conductive block 45 may be remelted and scattered outside. If the scattered solder adheres to other components mounted on the substrate 41 of the protection circuit, the external connection tab 46, or the like, there is a possibility of causing a defect such as occurrence of a short circuit.

  As a method for solving the above-mentioned problem, Patent Document 1 discloses a non-soldering portion in which soldering is not performed on a land portion where a circuit board and a conductive block are soldered at a position corresponding to a position where welding is performed. Is disclosed. Patent Document 2 discloses a structure in which a conductive plate larger than the circuit board is connected to the other surface of the circuit board on which the electrode pad is formed by caulking or soldering, and heat due to resistance welding is not easily transmitted to the solder. The technology to make is disclosed. Patent Document 3 discloses a technique for a circuit board having an opening for accepting or escaping the molten solder on the circuit board so that the molten solder does not scatter to the electronic component side on the circuit board. Yes.

JP 2004-304019 A JP 2005-322568 A JP 2005-44968 A

  However, Patent Document 1 has a problem that the position of the conductive block is shifted when the solder is remelted. Patent Document 2 has a problem that the overall dimensions of the circuit board are increased, a problem that a large number of processes are required to join the conductive plates, and a problem that processing of the circuit board is necessary. Increases the cost of the circuit board. Moreover, although patent document 3 makes the solution the limitation of the solder scattering direction, in a battery pack, solder scattering must be prevented with respect to all directions.

  Accordingly, an object of the present invention is to provide a circuit board and a circuit board manufacturing method that make it difficult to transfer heat to a solder for joining a circuit board and a conductive block. Also provided are a structure for preventing the solder melted by heat from scattering to the outside, a circuit board for preventing displacement of the conductive block due to remelting of the solder, and a method for manufacturing the circuit board. It is another object of the present invention to provide a circuit board and a circuit board manufacturing method that prevent an increase in overall dimensions and cost of the circuit board used in the battery pack.

  The present invention has been made as a result of reconsideration of the structure and connection method of a conductive block bonded to a circuit board in order to solve the above-mentioned problems.

  That is, the present invention has a solder receiving portion for preventing molten solder from splashing to the outside and a projection for joining the circuit substrate to a circuit substrate provided with conductive holes as electrode portions. A circuit board and a method of manufacturing the circuit board, wherein the conductive block is electrically and mechanically joined via solder.

  According to the present invention, there is provided a circuit board to which an external connection tab is welded to a conductive block soldered to an electrode portion formed on the board, wherein the board is provided with a conductive hole, and the conductive block is provided with the conductive block. A circuit board is obtained in which the provided protrusion is bonded to the conductive hole.

  According to the present invention, there is obtained a circuit board characterized in that a solder receiving portion is formed on the conductive block.

  According to the present invention, there is obtained a circuit board characterized in that the hole of the board penetrates the board.

  According to the present invention, there is obtained a circuit board characterized in that the holes of the board do not penetrate the board.

  According to the present invention, there is provided a circuit board to which an external connection tab is welded to a conductive block soldered to an electrode portion formed on the board, the conductive block being provided in the board, and the conductive block being provided in the conductive block. A method for manufacturing a circuit board is obtained, wherein the provided protrusion is bonded to the conductive hole.

  According to the present invention, there is obtained a circuit board manufacturing method characterized in that a solder receiving portion is formed on the conductive block.

  According to the present invention, there is obtained a method for manufacturing a circuit board, wherein the holes of the board pass through the board.

  According to the present invention, there is obtained a method for manufacturing a circuit board, wherein the holes of the board do not penetrate the board.

  According to the circuit board and the circuit board manufacturing method of the present invention, since solder does not exist in a portion where heat generated by resistance welding is directly generated, it becomes difficult to transfer heat generated by resistance welding to the solder. According to this structure, remelting of the solder is prevented, and even when the solder is melted, scattering to the outside can be prevented, so that defects caused by melting and scattering of the solder can be extremely reduced.

  Further, according to the circuit board and the circuit board manufacturing method of the present invention, the circuit board does not require any special processing other than the normal circuit board manufacturing process. There is an effect that can be prevented.

  Further, since the circuit board and the conductive block are joined by the conductive through hole as the electrode part provided on the circuit board and the projection provided on the conductive block, there is an effect of improving the position accuracy of the conductive block.

  In the circuit board and the circuit board manufacturing method of the present invention, when the conductive block and the external connection tab are welded, in order to make it difficult to transfer heat to the solder joining the board and the conductive block, The joint structure has been improved. A conductive hole is provided in the electrode part of the substrate, and a conductive receiving block is provided in the conductive block to prevent the molten solder from being scattered to the outside around the protruding part. The hole and the protrusion of the conductive block are combined, and the electrode portion of the substrate and the conductive block are electrically and mechanically joined by solder.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 shows the structure of a circuit board according to Embodiment 1 of the present invention. 1A is a plan view, FIG. 1B is a plan view of only a circuit board, FIG. 1C is a sectional view during welding, and FIG. 1D is a perspective view of a conductive block. Indicates.

In FIG. 1C, one specific example is shown. Reference numeral 11 denotes a circuit board, the base material is made of a glass fiber reinforced epoxy resin, and the thickness is 0.44 mm. Reference numeral 12 denotes a conductive through hole in which a hole as an electrode portion is covered with a copper foil, which is produced by a normal through-hole substrate process for producing a circuit board, and has a hole diameter of φ0.7 mm and a copper foil thickness of 30 μm. Reference numeral 13 denotes a resist for setting the solder application surface, and the thickness is 50 μm. 15 is a conductive block made of nickel, and the size is 3.0 mm in length, 3.0 mm in width, and 0.4 mm in thickness. Reference numeral 15a denotes a conductive block protrusion provided on the conductive block 15, which has a shape of φ0.5 mm and a length of 0.8 mm. 15b is a conductive block solder receiving portion provided in the conductive block 15, and its space volume is 0.34 mm ³ . 14 is solder, the composition is Su 96.5%, Ag 3.0%, Cu 0.5%, the melting point is 200 ° C. to 214 ° C., and the coating volume is 0.15 mm ³ . 16 is an external connection tab made of nickel. The size is 3.0 mm in width, 0.1 mm in thickness, and 3.0 mm in length (the length varies depending on the structure of the battery pack. Sometimes). Reference numeral 17 denotes an alumina-dispersed copper welding rod used for welding the conductive block and the external connection tab, and 18 denotes a region where heat generated by welding is transmitted. In this specific example, for example, the diameter of the welding rod 17 is 1.3 mm, the interval between welding rods is 0.4 mm, the applied pressure is 19.6 N, the energization time is 2.1 to 2.3 ms, and the energization current is 1.5 to 2.1 kA. Resistance welding of the external connection tab 16 to the conductive block 15 on the circuit board 11 is possible under the conditions of voltage 2.1 to 2.3V.

  Here, the length 19a of the solder receiving portion of the conductive block solder receiving portion 15b is larger than the length 19b of the solder application surface, and the space volume of the conductive block solder receiving portion 15b is larger than the application volume of the solder 14. You have to make it bigger. The conductive block 15 is in surface contact with the resist 13.

  As shown in FIG. 1C, the conductive block protrusion 15a is inserted into the conductive through hole 12 provided in the circuit board 11 and electrically and mechanically connected to the circuit board 11 via the solder 14. Soldered together.

  Next, the external connection tab 16 is resistance-welded with the welding rod 17 to the surface of the conductive block 15 joined to the circuit board 11. By performing welding, electrical and mechanical connection between the conductive block 15 and the external connection tab 16 can be secured.

  In FIG. 1C, the heat generated when the external connection tab 16 is electrically and mechanically connected to the conductive block 15 by resistance welding spreads like a region 18 where heat generated by welding is transmitted. As shown here, the effect of the heat generated during resistance welding is transmitted to the solder 14 by joining the circuit board 11 and the conductive block 15 with the conductive block protrusion 15a provided on the conductive block 15. It becomes difficult to prevent remelting of the solder.

  Further, since an air layer exists between the conductive block 15 and the solder 14 due to the conductive block solder receiving portion 15b, the thermal conductivity is lowered and remelting of the solder 14 is prevented. Even if the solder 14 is remelted, as is apparent from the structure of FIG. 1, the space volume of the conductive block solder receiving portion 15b is larger than the solder application volume. Accept and prevent splashing outside.

  Further, the structure in which the conductive block protrusion 15a provided on the conductive block 15 is inserted into the conductive through hole 12 of the circuit board 11 has an effect of improving the positional accuracy of the conductive block 15. In particular, as shown in FIG. 1, by providing the conductive block protrusion 15a and the two conductive through holes 12 of the circuit board 11, the rotational deviation at the time of bonding is prevented, and bonding is performed with more accurate positional accuracy. . In FIG. 1C, by making the length of the conductive block protrusion 15a of the conductive block 15 shorter than the thickness of the circuit board 11, the conductive block protrusion 15a of the conductive block 15 moves to the opposite surface of the circuit board 11. It can also be configured not to protrude. Further, by using the through-hole, the circuit board 11 and the conductive block 15 are firmly bonded, and the visual confirmation of the bonding state is also possible.

(Embodiment 2)
FIG. 2 shows the structure of the circuit board according to the second embodiment of the present invention. As shown in FIG. 2, the shape of the conductive block protrusion 25 a and the conductive non-through hole 22 as the electrode portion is not the conductive through hole of the circuit board 21. By doing so, the conductive block protrusion 25a of the conductive block 25 does not protrude to the opposite surface of the circuit board 21, so that the circuit board 21 can be designed to be directly installed on a flat component. Reference numeral 23 is a resist for setting the solder application surface, 24 is solder for connecting the circuit board 21 and the conductive block 25, and 25b is the thermal conductivity by the air layer when the conductive block 25 and the external connection tab 26 are resistance welded. A conductive block solder receiving portion that lowers and prevents remelting of the solder 24. Even if the solder 24 is remelted, the space volume of the conductive block solder receiving portion 15b is larger than the solder application volume, so that the solder 24 which is remelted and scattered outside is received and scattered outside. To prevent.

(Embodiment 3)
FIG. 3 shows an example of the arrangement of the projecting portions and solder receiving portions of the conductive block according to Embodiment 3 of the present invention, and conductive through holes provided in the circuit board. 3A is a perspective view of a conductive block, and FIG. 3B is a plan view of only a circuit board.

  FIG. 3A shows an example of the arrangement of the conductive block protrusion 33a, the conductive block solder receiving portion 33b, and the conductive through hole 32 as an electrode portion provided on the circuit board 31 in FIG. Indicates. As in the third embodiment, the conductive block protrusion 33 a provided on the conductive block 33 may be disposed at an angle with respect to the end face of the conductive block 33 instead of being parallel.

  Each member quality, shape, and size of the embodiment described above is an example, and the present invention is not limited to this example. The number and arrangement of the conductive block protrusions 15a and 25a of the conductive blocks 15 and 25, the number and arrangement of the conductive through holes 12 of the circuit board 11 and the conductive non-through holes 22 of the circuit board 21 are also determined by welding. The current direction can be changed according to the specifications required for joining the circuit boards 11 and 21 and the conductive blocks 15 and 25, but is not limited thereto.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to these embodiment, Even if there is a design change of the range which does not deviate from the summary of this invention, it is included in this invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

  By using the circuit board and the circuit board manufacturing method of the present invention, the present invention is applied to a circuit board and a circuit board manufacturing method suitable for battery packs, secondary batteries, and the like in fields where high reliability is required for welding and connection. it can.

The figure which shows the structure of the circuit board of Embodiment 1 of this invention. 1A is a plan view, FIG. 1B is a plan view of only a circuit board, FIG. 1C is a cross-sectional view during welding, and FIG. 1D is a perspective view of a conductive block. The figure which shows the structure of the circuit board of Embodiment 2 of this invention. The figure which shows an example of arrangement | positioning of the electroconductive through-hole provided in the board | substrate of the protrusion part and solder receiving part which a conductive block of Embodiment 3 of this invention has, and a circuit. FIG. 3A is a perspective view of a conductive block, and FIG. 3B is a plan view of only a circuit board. The figure which shows the structure of the protection circuit board by a prior art. 4A is a plan view, and FIG. 4B is a cross-sectional view during welding.

Explanation of symbols

11 Circuit Board 12 Conductive Through Hole 13 Resist 14 Solder 15 Conductive Block 15a Conductive Block Protrusion
15b Conductive block solder receiving portion 16 External connection tab 17 Welding rod 18 Heat transfer area 19a Solder receiving portion length 19b Solder coated surface length 21 Circuit substrate 22 Conductive non-through hole 23 Resist 24 Solder 25 Conductive block 25a Conductive block projecting portion 25b Conductive block solder receiving portion 26 External connection tab 31 Circuit board 32 Conductive through hole 33 Conductive block 33a Conductive block projecting portion 33b Conductive block solder receiving portion 41 Protection circuit substrate 42 Electrode Pad 43 Resist 44 Solder layer 45 Conductive block 46 External connection tab 47 Welding rod 48 Current direction 49 Heat transfer region 50 generated by welding Spatter of remelted solder

Claims (8)

  A circuit board in which a tab for external connection is welded to a conductive block soldered to an electrode portion formed on the board, wherein a conductive hole is provided in the substrate, and the protrusion provided on the conductive block is A circuit board characterized by being bonded to a conductive hole.   The circuit board according to claim 1, wherein a solder receiving portion is formed on the conductive block.   The circuit board according to claim 1, wherein a hole of the board passes through the board.   The circuit board according to claim 1, wherein a hole of the board does not penetrate the board.   A circuit board in which a tab for external connection is welded to a conductive block soldered to an electrode portion formed on the board, wherein a conductive hole is provided in the substrate, and the protrusion provided on the conductive block is A method of manufacturing a circuit board, comprising bonding to a conductive hole.   6. The method for manufacturing a circuit board according to claim 5, wherein a solder receiving portion is formed in the conductive block.   7. The method of manufacturing a circuit board according to claim 5, wherein the hole of the board passes through the board.   7. The method of manufacturing a circuit board according to claim 5, wherein the hole of the board does not penetrate the board.

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