Structure and method of soldering and assembled battery and manufacturing method of assembled battery

Abstract

To provide a structure and a method of soldering which enables a user to check a state of a solder portion, and to provide an assembled battery and a manufacturing method of the assembled battery.SOLUTION: A soldering structure includes: a first member having a first surface and a metal portion provided on the first surface; a second member having a second surface which faces the first surface of the first member in a first direction; and a soldering portion provided between the metal portion of the first member and the second surface of the second member and configured to join the first member and the second member to each other. When viewed in a second direction orthogonal to the first direction, the metal portion has a first edge end. The soldering portion is provided so as to reach the first edge end. The second member has a through hole and the through hole is formed in an area crossing the first edge end in a third direction orthogonal to the first direction and the second direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present technology relates to a soldering structure and a soldering method, as well as a battery pack and a manufacturing method thereof. [Background technology]

[0002] Japanese Patent Application Laid-Open No. 2010-092988 (Patent Document 1) discloses that an electronic component has electrodes arranged on the underside of the package to connect to terminals of an element, and that is provided with through holes that pass through the package from top to bottom.

[0003] Japanese Patent Laid-Open Publication No. 2013-026445 (Patent Document 2) discloses a connection structure in which a hole through which molten solder can pass is formed at the joint between an upper electrode and a lower electrode. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-092988 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-026445 Summary of the Invention [Problem to be solved by the invention]

[0005] To improve the quality of soldered joints, it is necessary to make it easier to check the state of the joint. However, there is still room for improvement in conventional joint structures.

[0006] An object of the present technology is to provide a soldering structure and a soldering method that allow the state of the soldered portion to be easily confirmed, as well as a battery pack and a method for manufacturing the same. [Means for solving the problem]

[0007] The present technology provides the following soldering structure and soldering method, as well as a battery pack and a method for manufacturing the same.

[0008] [1] A soldering structure comprising: a first member having a first surface and a metal portion provided on the first surface; a second member having a second surface facing the first surface of the first member in a first direction; and a solder portion provided between the metal portion of the first member and the second surface of the second member, joining the first member and the second member; when viewed from a second direction perpendicular to the first direction, the metal portion has a first edge and the solder portion is provided to reach the first edge; and the second member has a through hole, the through hole being formed in a region spanning the first edge in a third direction perpendicular to the first direction and the second direction.

[0009] [2] The soldering structure according to [1], wherein the solder portion includes a fillet formed at a position adjacent to the first edge.

[0010] [3] The soldering structure according to [2], wherein the inclination angle of the fillet at the boundary with the metal portion is 10° or more and 45° or less.

[0011] [4] A soldering structure according to [2] or [3], wherein the first member has a second edge located on the opposite side of the first edge relative to the fillet, and the through hole is formed in an area spanning the second edge in the third direction.

[0012] [5] A soldering structure according to any one of [1] to [4], wherein the first member includes a flexible printed circuit board and the second member is a metal plate-shaped member.

[0013] [6] The soldering structure according to any one of [1] to [5], wherein the thickness of the second member in the first direction is 0.2 mm or more and 3.5 mm or less.

[0014] [7] A soldering structure described in any one of [1] to [6], wherein the through hole has a first width in the second direction and a second width in the third direction, and the second width is larger than the first width.

[0015] [8] A soldering method comprising the steps of: preparing a first member having a first surface and a metal portion provided on the first surface; preparing a second member having a second surface; providing molten solder on the metal portion of the first member; arranging the first member and the second member so that the first surface of the first member faces the second surface of the second member in a first direction and the molten solder is located between the metal portion of the first member and the second surface of the second member; and solidifying the molten solder to join the first member and the second member, wherein, when viewed from a second direction perpendicular to the first direction, the metal portion has a first edge and the solder is provided to reach the first edge, and the second member has a through hole, and in the step of arranging the first member and the second member, the first member and the second member are arranged so that the through hole straddles the first edge in a third direction perpendicular to the first direction and the second direction.

[0016] [9] The soldering method according to [8], wherein a fillet is formed in the solidified solder at a position adjacent to the first edge.

[0017]

[10] The soldering method according to [9], wherein the inclination angle of the fillet at the boundary with the metal portion is 10° or more and 45° or less.

[0018]

[11] A soldering method according to [9] or

[10] , wherein the first member has a second edge located on the opposite side of the fillet from the first edge, and the through hole is formed in an area spanning the second edge in the third direction.

[0019]

[12] The soldering method according to any one of [8] to

[11] , wherein the first member includes a flexible printed circuit board and the second member is a metal plate-shaped member.

[0020]

[13] The soldering method according to any one of [8] to

[12] , wherein the thickness of the second member in the first direction is 0.2 mm or more and 3.5 mm or less.

[0021]

[14] A soldering method according to any one of [8] to

[13] , wherein the through hole has a first width in the second direction and a second width in the third direction, the second width being larger than the first width.

[0022]

[15] A battery pack including the soldering structure according to any one of [1] to [7].

[0023]

[16] A method for manufacturing a battery pack, comprising the soldering method according to any one of [8] to

[14] . [Effects of the Invention]

[0024] According to the present technology, in a soldering structure and a soldering method, the state of the soldered portion can be easily confirmed, thereby improving the quality of the soldered connection of members. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a diagram showing a basic configuration of a battery module. [Figure 2] FIG. 2 is a perspective view showing a battery cell. [Figure 3] FIG. 10 is a perspective view showing a state in which a wiring module is provided on a battery module. [Figure 4] FIG. 2 is a diagram showing the arrangement of bus bars in a battery pack. [Figure 5] FIG. 2 is a diagram showing an example of a joining structure of members. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI in FIG. 5. [Figure 7] FIG. 7 is an enlarged view showing the periphery of a fillet in the cross section shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0027] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0028] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0029] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0030] In this specification, the term "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the term "electrode" may collectively refer to positive and negative electrodes. Furthermore, the term "electrode plate" may collectively refer to positive and negative plates.

[0031] In this specification, "battery cells" are not necessarily limited to prismatic ones, but may also include cells of other shapes, such as cylindrical, pouch, and blade types. Furthermore, "batteries" can be installed in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of "batteries" is not limited to in-vehicle use.

[0032] 1 is a diagram showing the basic configuration of a battery pack 1. As shown in FIG. 1, the battery pack 1 includes battery cells 100, end plates 200, and restraining members 300.

[0033] The multiple battery cells 100 are arranged in a line in the Y-axis direction. This forms a stack of the battery cells 100. The battery cells 100 include electrode terminals 110. Separators (not shown) are interposed between the multiple battery cells 100. The multiple battery cells 100 sandwiched between the two end plates 200 are pressed by the end plates 200 and are constrained between the two end plates 200.

[0034] The end plates 200 are arranged on both ends of the battery pack 1 in the Y-axis direction. The end plates 200 are fixed to a base such as a case that houses the battery pack 1. The restraining members 300 connect the two end plates 200 to each other.

[0035] By fixing the restraining members 300 to the end plates 200 while a compressive force in the Y-axis direction is applied to the stack of multiple battery cells 100 and end plates 200, and then releasing the compressive force, a tensile force acts on the restraining members 300 connecting the two end plates 200. In reaction to this, the restraining members 300 press the two end plates 200 in a direction that brings them closer to each other.

[0036] Fig. 2 is a perspective view showing the battery cell 100. As shown in Fig. 2, the battery cell 100 has a rectangular shape. The battery cell 100 has electrode terminals 110 and a housing 120 (external can). In other words, the battery cell 100 is a rectangular secondary battery cell.

[0037] The electrode terminal 110 is formed on the housing 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112 that are aligned along the X-axis direction that is perpendicular to the Y-axis direction. The positive electrode terminal 111 and the negative electrode terminal 112 are spaced apart from each other in the X-axis direction.

[0038] The housing 120 has a rectangular parallelepiped shape and forms the exterior of the battery cell 100. The housing 120 includes a case body 120A that houses an electrode assembly and an electrolyte (not shown), and a sealing plate 120B that seals the opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

[0039] The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and two third side surfaces 125. The housing 120 is provided with a gas exhaust valve 126.

[0040] The upper surface 121 is a plane perpendicular to the Z-axis direction, which is perpendicular to the Y-axis direction and the X-axis direction. The electrode terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

[0041] Each of the first side surface 123 and the second side surface 124 is made of a plane perpendicular to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the housing 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction, with the X-axis direction being the longitudinal direction and the Z-axis direction being the lateral direction.

[0042] The multiple battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the battery cells 100 adjacent to each other in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

[0043] Gas exhaust valve 126 is provided on top surface 121. When the temperature of battery cell 100 rises (thermal runaway) and the internal pressure of housing 120 exceeds a predetermined value due to gas generated inside housing 120, gas exhaust valve 126 exhausts the gas to the outside of housing 120.

[0044] Fig. 3 is a perspective view showing a state in which a wiring module is provided on the battery pack 1. As shown in Fig. 3, a plate member 400 is placed on the battery pack 1, and a wiring member 500 is provided on the plate member 400. The wiring member 500 can be electrically connected to an external device via a connector 600. A cover member 700 is provided on the plate member 400 so as to cover the wiring member 500.

[0045] Fig. 4 is a diagram showing the arrangement of bus bars 800 in the battery pack 1. In the example of Fig. 4, the positive electrode terminals 111 and negative electrode terminals 112 of adjacent battery cells 100 are electrically connected by the bus bars 800, and the plurality of battery cells 100 are electrically connected in series.

[0046] That is, the battery pack 1 includes a plurality of battery cells 100, each having an electrode terminal 110, arranged along a predetermined direction (Y-axis direction), and a bus bar 800 that connects the electrode terminals 110 of the plurality of battery cells 100 together.

[0047] Fig. 5 is a diagram showing an example of a joining structure of a plurality of members in a wiring member 500. As shown in Fig. 5, the wiring member 500 includes a flexible printed circuit board 510 (first member) and a terminal member 520 (second member).

[0048] The flexible printed circuit board 510 has a structure in which a flexible thin-film insulating film and a conductive foil are bonded together using an adhesive, and can be repeatedly deformed with a weak force. In the flexible printed circuit board 510, the insulating film is made of, for example, polyimide, and the conductive foil is made of, for example, copper foil. The conductive foil of the flexible printed circuit board 510 forms the wiring in the wiring member 500.

[0049] The terminal member 520 may be configured as a plate-like member made of a conductive material such as metal (more specifically, aluminum). One end of the terminal member 520 (the left end in FIG. 5) is disposed so as to overlap the flexible printed circuit board 510 in the Z-axis direction (first direction). The other end of the terminal member 520 (the right end in FIG. 5) is joined to the bus bar 800. The thickness of the terminal member 520 may be, for example, approximately 0.2 mm to 3.5 mm (preferably approximately 0.2 mm to 1.0 mm, and more preferably approximately 0.5 mm to 0.8 mm). However, the material and thickness of the terminal member 520 are not limited to the above ranges.

[0050] Terminal member 520 has through-hole 520A. Through-hole 520A has an elongated shape that is longer in the X-axis direction than in the Y-axis direction. That is, when the width (first width) of through-hole 520A in the Y-axis direction (second direction) is compared with the width (second width) in the X-axis direction (third direction), the width in the X-axis direction is larger than the width in the Y-axis direction.

[0051] In one example, the width of through hole 520A in the Y-axis direction is approximately 0.1 mm to 10.0 mm (preferably approximately 0.8 mm to 7.0 mm), and the width of through hole 520A in the X-axis direction is approximately 0.2 mm to 40.0 mm (preferably approximately 1.6 mm to 14.0 mm). The ratio of the width in the X-axis direction (second width) to the width in the Y-axis direction (first width) is approximately 1:2 to 1:4. However, the width of through hole 520A is not limited to the above range.

[0052] The wiring provided inside flexible printed circuit board 510 is electrically connected to terminal member 520 via solder joint. By joining terminal member 520 and bus bar 800, wiring member 500 and bus bar 800 are electrically connected.

[0053] 5, an end of the flexible printed circuit board 510 extending in the Y-axis direction and an end of the terminal member 520 extending in the X-axis direction are overlapped and joined to each other. The shapes and arrangements of the flexible printed circuit board 510 and the terminal member 520 are not limited to those shown in FIG.

[0054] Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. As shown in Fig. 6, the flexible printed circuit board 510 has a first surface 511, and the terminal member 520 has a second surface 521 facing the first surface 511.

[0055] Lands 510A (metal portions) for solder connection are provided on a first surface 511 of the flexible printed circuit board 510. The flexible printed circuit board 510 and the terminal members 520 are joined by solder portions 530 provided between the lands 510A and the terminal members 520, and the wiring in the flexible printed circuit board 510 and the terminal members 520 are electrically connected.

[0056] The thickness of the land 510A can be, for example, about 12 μm to 175 μm (preferably about 30 μm to 70 μm). The land 510A can be made of a metal such as copper. However, the thickness and material of the land 510A are not limited to the above ranges and materials.

[0057] When joining flexible printed circuit board 510 and terminal member 520, molten solder is provided on land 510A, and terminal member 520 is placed on top of it. When the molten solder solidifies, solder portion 530 is formed. The thickness of solder portion 530 can be, for example, approximately 0.1 mm or more and 0.15 mm or less. However, the thickness of solder portion 530 is not limited to the above range.

[0058] When viewed from the Y-axis direction (the cross-sectional direction shown in FIG. 6), the land 510A has an edge 10 (first edge), and the flexible printed circuit board 510 has an edge 20 (second edge). In this embodiment, when viewed from the Z-axis direction, the edges 10 and 20 are formed parallel to each other. However, the edges 10 and 20 may be formed so as to intersect each other obliquely.

[0059] The through hole 520A of the terminal member 520 is formed in a region that straddles the edge 10 of the land 510A and the edge 20 of the flexible printed circuit board 510 in the X-axis direction. Therefore, when viewed from the Z-axis direction, the edge 10 of the land 510A and the edge 20 of the flexible printed circuit board 510 can be seen through the through hole 520A. The through hole 520A does not necessarily have to be formed so as to straddle the edge 20 of the flexible printed circuit board 510.

[0060] The solder portion 530 can be formed of a commonly used lead-free solder. In one example, the composition of the solder portion 530 is Sn-3.0Ag-0.5Cu, and the melting point of the solder portion 530 made of this composition is about 217°C. However, the composition of the solder portion 530 is not limited to the above.

[0061] The solder portion 530 includes a fillet 531 formed adjacent to the edge 10. As described above, in the connection structure of this embodiment, the through hole 520A is formed in a region spanning the edge 10 of the land 510A. Therefore, when viewed from the Z-axis direction, the edge 10 of the land 510A can be visually confirmed through the through hole 520A. This makes it possible to confirm the state of the fillet 531 adjacent to the edge 10 and easily determine whether the soldering is good or bad. As a result, the quality of the soldered connection of components can be improved without complicating the process. Note that the method for checking the soldering state is not limited to visual confirmation, and confirmation using an image inspection machine, for example, may also be used.

[0062] 7 is an enlarged view showing the periphery of fillet 531. The inclination angle (θ in FIG. 7) of fillet 531 at the boundary with land 510A is preferably approximately 10° or more and 45° or less. However, the inclination angle of fillet 531 is not limited to the above range.

[0063] In this embodiment, the soldering structure between the flexible printed circuit board 510 and the terminal member 520 has been described, but the application scope of the present technology is not limited to the above example, and may also be applied to other soldering structures in the battery pack 1. Furthermore, the application scope of the present technology is not limited to the battery pack 1, and may also be applied to soldering structures at any location in electrical and electronic devices other than batteries.

[0064] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0065] 1 battery pack, 10 edge, 20 edge, 100 battery cell, 110 electrode terminal, 111 positive terminal, 112 negative terminal, 120 housing, 120A case body, 120B sealing plate, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 126 gas release valve, 200 end plate, 300 restraining member, 400 plate member, 500 wiring member, 510 flexible printed circuit board, 510A land, 511 first surface, 520 terminal member, 520A through hole, 521 second surface, 530 solder portion, 531 fillet, 600 connector, 700 cover member, 800 bus bar.

Claims

1. a first member having a first surface and a metal portion disposed on the first surface; a second member having a second surface facing the first surface of the first member in a first direction; a solder portion provided between the metal portion of the first member and the second surface of the second member, the solder portion joining the first member and the second member; When viewed from a second direction perpendicular to the first direction, the metal portion has a first edge, and the solder portion is provided so as to reach the first edge; A soldering structure, wherein the second member has a through hole, the through hole being formed in a region spanning the first edge in the first direction and a third direction perpendicular to the second direction.

2. The soldering structure of claim 1 , wherein the solder portion includes a fillet formed adjacent the first edge.

3. The soldering structure according to claim 2 , wherein the inclination angle of the fillet at the boundary with the metal portion is 10° or more and 45° or less.

4. the first member has a second edge located opposite the first edge with respect to the fillet; The soldering structure according to claim 2 or 3, wherein the through-hole is formed in a region spanning the second edge in the third direction.

5. 4. The soldering structure according to claim 1, wherein the first member includes a flexible printed circuit board, and the second member is a metal plate-like member.

6. The soldering structure according to claim 1 , wherein the thickness of the second member in the first direction is not less than 0.2 mm and not more than 3.5 mm.

7. 4. The soldering structure of claim 1, wherein the through hole has a first width in the second direction and a second width in the third direction, the second width being greater than the first width.

8. providing a first member having a first surface and a metal portion disposed on the first surface; providing a second member having a second surface; providing molten solder on the metal portion of the first member; arranging the first member and the second member so that the first surface of the first member faces the second surface of the second member in a first direction and the molten solder is located between the metal portion of the first member and the second surface of the second member; and solidifying the molten solder to join the first member and the second member together. When viewed from a second direction perpendicular to the first direction, the metal portion has a first edge, and the solder is provided so as to reach the first edge; A soldering method in which the second member has a through hole, and in the process of arranging the first member and the second member, the first member and the second member are arranged so that the through hole straddles the first edge in a third direction perpendicular to the first direction and the second direction.

9. The soldering method of claim 8 , wherein a fillet is formed in the solidified solder adjacent to the first edge.

10. 10. The soldering method according to claim 9, wherein the inclination angle of the fillet at the boundary with the metal portion is 10 degrees or more and 45 degrees or less.

11. the first member has a second edge located opposite the first edge with respect to the fillet; 11. The soldering method according to claim 9, wherein the through-hole is formed in a region that straddles the second edge in the third direction.

12. 11. The soldering method according to claim 8, wherein the first member includes a flexible printed circuit board, and the second member is a metal plate-like member.

13. 11. The soldering method according to claim 8, wherein the thickness of the second member in the first direction is not less than 0.2 mm and not more than 3.5 mm.

14. 11. The soldering method according to claim 8, wherein the through hole has a first width in the second direction and a second width in the third direction, the second width being greater than the first width.

15. A battery pack comprising the soldering structure according to any one of claims 1 to 3.

16. A method for manufacturing a battery pack, comprising the soldering method according to any one of claims 8 to 10.

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