button cell connector

Abstract

Button cell connector (10) for electrically connecting a printed circuit board (1) and a button cell (2), in which a direction along a plane direction of the button cell is defined as an X-axis direction, a direction along the plane direction perpendicular to the X-axis is defined as a Y-axis direction, and a direction perpendicular to the X-axis direction and to the Y-axis direction and along a thickness direction of the button cell is defined as a Z-axis direction, wherein the button cell connector has: a spring contact terminal (11) which is pressed through an outer circumferential surface (4a) of a positive electrode (4) of the button cell and is arranged in a spring shape which deforms elastically according to a pressing force exerted by the button cell in the X-axis direction and in the Z-axis direction; a plate connection (12) that is connected to the printed circuit board; and a pressing force absorption spring section (13) which is arranged between the plate connection and the spring contact terminal in order to be elastically deformable, and which absorbs the pressing force of the button cell which is received at the spring contact terminal by elastic deformation irrespective of the presence or absence of a cell holder which defines a position of the button cell, wherein the pressing force absorption spring section has a distal end section connected to the spring contact terminal and includes a curved arm (14) arranged in a spring shape which deforms elastically in accordance with the pressing force from the button cell in the X-axis direction and in the Y-axis direction in order to absorb the pressing force from the button cell, wherein the pressing force absorption spring section includes: a stepped surface (15) arranged in a stepped manner with respect to the plate connection; and a curved piece (16) which is bent in the Z-axis direction from a rear end of the stepped surface and perpendicular to the stepped surface, and which has a side section connected to a rear end of the bent arm.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] This application is based on the Japanese patent application number JP 2015 - 95 309 A, filed on November 11, 2013, the full disclosure of which is hereby incorporated by reference. TECHNICAL AREA

[0002] The present disclosure relates to a button cell connector for electrically connecting a button cell and a printed circuit board. BACKGROUND

[0003] In electrical devices or equipment, such as a wireless car transmitter or similar device, that use button cells as their power source, a button cell connector is conventionally provided for electrically connecting a button cell to a printed circuit board, as disclosed, for example, in patent document 1. JP 2004-87 191 A proposes a cell holder mounted on the circuit board to define the positional relationship between the button cell and the connector. However, this configuration imposes limitations on the circuit board design due to the shape required for assembling the cell holder. Connectors exist that do not require cell holders, but most of these must be manually attached and are not suitable for automated assembly (soldering).For this reason, the positioning precision of the button cell is low (the button cell can easily move) and the cell is subjected to high stress. Large through-holes (holes for inserting components for mounting) and solder pads (copper foil for soldering) are therefore essential to provide robust solder joints. This results in less available installation space and limits the printed circuit board design.

[0004] Button cell terminals are prone to plastic deformation due to their structure, where the cell insertion direction and the deformation / stress direction differ (the vectors are perpendicular to each other). Should this occur, the plastic deformation leads to a connection failure. There are also terminals that are not mounted on a printed circuit board (PCB contact terminals). However, if these are subjected to vibration or dropped, a sudden break in this type of terminal is highly likely, and consequently, there is a possibility of oxidation of the contacts (fretting corrosion). These terminals are therefore susceptible to connection failures and can shorten the product lifespan.

[0005] Furthermore, reference is made to US 5 931 693 A, which features a button cell connector for electrically connecting a circuit board and a button cell. OVERVIEW OF THE INVENTION

[0006] One objective of the present disclosure is to provide a button cell connector for use in a cell holder-free configuration, which improves the degree of freedom of a printed circuit board design by avoiding the need for large through holes or solder pads, and which is mounted on a printed circuit board without causing connection errors.

[0007] According to one aspect of the present disclosure, a button cell connector for electrically connecting a printed circuit board and a button cell comprises a spring contact connector, a plate connector attached to the printed circuit board, and a pressure-force-absorbing spring connector. If a direction along a plane direction of the button cell is defined as an X-axis direction; a direction along the plane direction and perpendicular to the X-axis is defined as a Y-axis direction; and a direction perpendicular to the X-axis and Y-axis directions and along a thickness direction of the button cell is defined as a Z-axis direction, the spring contact connector is pressed through an outer circumferential surface of a positive electrode of the button cell and is arranged in a spring shape that deforms elastically according to a pressing force exerted by the button cell in the X-axis and Z-axis directions.The plate connection is connected to the printed circuit board; and the pressure-absorbing spring section is arranged between the plate connection and the spring contact terminal to be elastically deformable, and absorbs the pressure force of the button cell received at the spring contact terminal by elastic deformation regardless of the presence or absence of a cell holder defining a position of the button cell. Furthermore, the pressure-absorbing spring section has a distal end section connected to the spring contact terminal and includes a curved arm arranged in a spring shape that deforms elastically according to the pressure force from the button cell in the X-axis direction and in the Y-axis direction to absorb the pressure force from the button cell.

[0008] As explained above, the button cell connector includes the spring contact terminal, which is designed in a spring shape that deforms elastically according to a pressing force from the button cell in the X-axis and Z-axis directions, and the curved arm, which is also designed in a spring shape that absorbs the pressing force from the button cell using spring-back deformation according to the pressing force from the button cell in the X-axis and Y-axis directions. Therefore, even if the button cell connector is subjected to high stress due to misalignment between the button cell and the connector caused by dropping or vibration in a configuration where a cell holder is not provided, such stress can be absorbed without robust solder connections.This eliminates the need for large through-holes or solder pads to provide robust solder connections, thus improving the degree of freedom in PCB design. Similarly, in a configuration where the button cell connector is mounted on the PCB, sudden interruptions or connection failures of the button cell connector mounted on the PCB can be prevented, as the spring contact connector and the curved arm ensure a spring reaction force to guarantee high contact pressure between the connector and the button cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The foregoing and further tasks, features, and advantages of the present disclosure will become more apparent from the following detailed description in conjunction with the drawings. The drawings include: Fig. 1 is a side view illustrating a printed circuit board with a button cell connector according to an embodiment of the present disclosure, which is mounted on the printed circuit board, and a button cell; Fig. Figure 2 is a perspective view illustrating the button cell connector; Fig. Figure 3 is a side view illustrating the button cell connector; and Fig. Figure 4 is a perspective view illustrating the button cell connector in a modification. FORMS OF EXECUTION OF THE INVENTION

[0010] An embodiment of a button cell connector of the present disclosure is described below with reference to the drawings. The button cell connector of this embodiment is applied to electrical equipment such as a wireless car transmitter or the like, for example, which wirelessly transmits a signal to activate a car door locking device to a receiver attached to the car and establishes an electrical connection between the button cell and a circuit board.

[0011] A printed circuit board 1, on which various electrical parts of an electronic component unit are mounted, is enclosed in a housing (not shown) which is part of electrical equipment, as shown in Fig. Figure 1 shows an integrated circuit (IC) that controls the operation of the electrical equipment and a cell connector 3 that holds a button cell 2, which is to be the power source of the electrical equipment in electrical connection with it, are mounted on the mounting surface of the circuit board 1.

[0012] Cell terminal 3 includes a positive cell terminal 10 (corresponding to the button cell terminal), which is connected to a positive electrode 4 of button cell 2, and a negative cell terminal 20, which is connected to a negative electrode 5 of button cell 2, and is made entirely of metal to form an electrical contact point with button cell 2. These terminals 10 and 20 are attached to the circuit board 1, for example by soldering or similar means.

[0013] The positive cell terminal 10 includes, as in Fig. 2 and Fig. Figure 3 shows a pair of right and left spring contact terminals 11, which contact an outer circumferential surface 4a of the positive electrode 4 of the button cell 2, which is pressed against the spring contact terminals; a pair of right and left plate connections 12, which are connected to the circuit board 1; and a pressure force absorption spring section 13, which is provided between the spring contact terminals 11 and the plate connections 12 to be elastically deformable. The spring contact terminals 11, the plate connections 12, and the pressure force absorption spring section 13 are manufactured from sheet metal (conductive component) in one piece.

[0014] The spring contact terminals 11 are designed in a spring shape that expands elastically according to the pressing force from the button cell 2 in a longitudinal direction, in other words a longitudinal direction of the positive cell terminal 10 (X-axis direction, which in Fig. 1 to Fig. 3 is shown) and in a vertical direction (Z-axis direction, which is shown in Fig. 1 to Fig. (as shown in Figure 3) is deformed. The plate connections 12 have mounting sections on their back side that are attached to the circuit board 1 with solder. When they are not connected to (attached to) the circuit board 1, the plate connections 12 are in a shape that provides a support surface for carrying the positive cell terminal 10 in a self-supporting manner or in a self-supporting state.

[0015] In the present disclosure, the longitudinal direction (X-axis direction) relates to a direction along a plane direction of the button cell 2, while the transverse direction (Y-axis direction) relates to a direction along a plane direction of the button cell 2 and perpendicular to the longitudinal direction. The vertical direction (Z-axis direction) relates to a direction perpendicular to the longitudinal and transverse directions and along a thickness direction of the button cell 2. In the present disclosure, "perpendicular" includes not only exactly perpendicular but also substantially perpendicular angles.

[0016] The pressure-absorbing spring section 13 comprises curved arms 14 having distal ends connected to respective spring contact terminals 11, a stepped surface 15 formed in a stepped manner with respect to the plate connections 12, and a curved section 16 bent substantially perpendicularly upwards from the rear end of this stepped surface 15, and absorbs the pressing force from the button cell 2 received through the spring contact terminals 11 by means of rebound deformation. The circuit board 1 of this embodiment does not include a cell holder for defining the position of the button cell 2. The pressure-absorbing spring section 13 absorbs the pressing force from the button cell 2 regardless of whether a cell holder is present or not.

[0017] The curved arms 14 are provided as a pair of right and left arms corresponding to the pair of right and left spring contact terminals 11, respectively. The curved arms 14 are bent in an XY plane that extends along a transverse direction of the button cell 2, in other words, in the lateral direction of the positive cell terminal 10 (Y-axis direction, which is in Fig. 2), and extends in the longitudinal direction (X-axis direction), and absorb the pressing force from the button cell 2 by spring-back deformation according to the pressing force in the longitudinal direction (X-axis direction) and transverse direction (Y-axis direction) of the button cell 2. The rear ends of the pair of right and left curved arms 14 are connected to both ends of the curved piece 16. The positive cell terminal 10, which has the pair of right and left spring contact terminals 11, the plate connections 12 and the curved arms 14, is symmetrically formed on the right and left sides in the Y-axis direction, which is its lateral direction.

[0018] The negative cell terminal 20 comprises a metal-like base 21 and a pair of flexible sections 22 and is mounted on the circuit board 1 on the back of the base 21 as the soldered section. When the button cell 2 is inserted into the cell terminal 3, the negative cell terminal 20 contacts the negative electrode 5 of the button cell 2 with the pair of flexible sections 21, which are bent. Thus, the flexible sections 21 assume a state in which they push the button cell 2 upwards, so that the top of the button cell 2 is pressed against a support (not shown) of the housing, which forms part of the electrical assembly, and the button cell 2 is thereby secured in position within the housing.

[0019] Next, the effects of the positive cell terminal 10 are described. If the electrical equipment containing the circuit board 1 is dropped or subjected to vibration, the positive cell terminal 10 receives an impact load from the button cell 2. This impact load is exerted on the positive cell terminal 10 in directions where there may be some looseness around the button cell 2, namely in the longitudinal (X-axis), transverse (Y-axis), and vertical (Z-axis) directions of the button cell 2. The positive cell terminal 10 receives this impact load from the button cell via the right and left spring contact terminals 11, which are in contact with the outer circumferential surface 4a of the positive electrode 4.

[0020] The spring contact terminals 11 of the positive cell terminal 10 are designed in a spring shape which deforms elastically according to the pressing force from the button cell 2 in the longitudinal direction (X-axis direction) and the vertical direction (Z-axis direction) of the button cell 2 as described above, so that the spring contact terminals 11 bend or deform along the X-axis direction and the Z-axis direction in order to absorb the shock load from the button cell 2 in the X-axis direction and the Z-axis direction.Furthermore, the curved arms 14, which form the pressure force absorption spring section 13, are designed in a spring shape which deforms elastically according to the pressure force from the button cell 2 in the longitudinal direction (X-axis direction) and the transverse direction (Y-axis direction) of the button cell 2, so that the curved arms 14 bend or deform along the X-axis direction and the Y-axis direction in order to absorb the impact load from the button cell 2 in the X-axis direction and the Y-axis direction.

[0021] The stepped surface and the curved section 16, which form the pressure-absorbing spring section 13, are positioned between the plate connections 12 and the curved arms 14. Thus, a portion of the impact load from the button cell 2, which cannot be absorbed by the spring contact terminals 11 and the curved arms 14, is distributed across the stepped surface 15 and the curved section 16, so that the impact load from the button cell 2 is hardly exerted on the plate connections 12. Even if the electrical equipment is dropped and the circuit board 1 is subjected to vibration, the impact load exerted by the button cell 2 towards the positive cell terminal 10 barely reaches the plate connections 12 directly. Therefore, the impact resistance of the positive cell terminal 10 is improved.

[0022] As described above, according to the configuration of this embodiment, the positive cell terminal 10, which electrically connects the button cell 2 to the circuit board 1, includes the spring contact terminal 11, the plate connection 12, which is connected to the circuit board 1, and the pressing force absorption spring section 13. The spring contact terminal 11 makes contact with an outer circumferential surface of the positive electrode of the button cell 2, which is pressed against the spring contact terminal 11, and is designed in a ring shape that deforms elastically according to the pressing force in the longitudinal and vertical directions of the button cell 2.The pressure force absorption spring section 13 is designed to be elastically deformable between the plate connection 12 and the spring contact terminal 11, and absorbs the pressure force from the button cell 2 received at the spring contact terminal 11 by means of its own rebound deformation, regardless of whether or not there is a cell holder defining a position for the button cell 2. The pressure force absorption spring section 13 includes the curved arm 14, which has a distal end connected to the spring contact terminal 11 and is designed in a spring shape that deforms elastically in accordance with the pressure force from the button cell 2 in the longitudinal and transverse directions of the button cell 2 in order to absorb the pressure force from the button cell 2.

[0023] As described above, the positive cell terminal 10 includes the spring contact terminal 11, which is designed in a spring shape that deforms elastically according to the pressing force in the longitudinal and vertical directions of the button cell 2, and the curved arm 14, which absorbs the pressing force from the button cell 2 by spring-back deformation according to the pressing force in the longitudinal and transverse directions of the button cell 2. Therefore, even in a configuration without a cell holder, in a case where the positive cell terminal 10 is subjected to high stress due to misalignment between the button cell 2 and the positive cell terminal 10 as a result of a fall or vibration, such stress can be absorbed without robust solder connections.This eliminates the need for large through-holes and solder pads to provide robust solder connections, thereby increasing the degree of freedom in printed circuit board design. In a configuration where the positive cell terminal 10 is mounted on the circuit board 1, the spring reaction force of the spring contact terminal 11 and the curved arm 14 provides a high contact pressure between the terminal and the button cell 2, thus preventing a sudden interruption or connection failure between the cell and the positive terminal 10 on the circuit board 1. Furthermore, omitting the cell holder reduces the number of components and the size of the electrical equipment.

[0024] The plate connection 12 is designed in a form that provides a support surface for holding the positive cell terminal 10 in a self-supporting state when it is not connected to the circuit board 1. Since the positive cell terminal 10 can be manufactured to stand alone, automated attachment (soldering) of the positive cell terminal 10 to the circuit board 1 is possible.

[0025] The spring-loaded force absorption section 13 also includes the stepped surface 15, which is stepped with respect to the plate connection 12, and a bent piece 16, which is bent substantially perpendicularly from the rear end of this stepped surface 15, the bent piece 16 having a side section that is connected to a rear end of the bent arm 14. In this way, the stepped surface 15 and the bent piece 16 can be positioned between the plate connection 12 and the bent arm 14. Thus, a portion of the shock load from the button cell 2, which cannot be absorbed by the spring contact terminal 11 and the bent arm 14, is distributed across the stepped surface 15 and the bent piece 16, so that the shock load from the button cell 2 is hardly exerted on the plate connection 12.

[0026] The spring contact terminal 11 is provided as a pair of right and left terminals that make contact with different discrete sections of the outer circumferential surface 4a of the positive electrode 4 of the button cell 2, and the curved arm 14 is provided as a pair of right and left arms corresponding to this pair of right and left spring contact terminals 11, respectively. Accordingly, the positive cell terminal 10 can be connected to the positive electrode of the button cell 2 in a state in which the outer circumferential surface 4a of the positive electrode 4 of the button cell 2 is held on both sides by the right and left spring contact terminals 11, which are connected to the respective distal ends of the right and left curved arms 14.

[0027] The spring contact terminal 11, the plate connection 12, and the pressing force absorption spring section 13 are all manufactured in one piece from a sheet-like conductive component. Consequently, a reliable electrical connection is established between the different forming elements (spring contact terminal 11, plate connection 12, and pressing force absorption spring section 13), and the number of components can also be reduced.

[0028] Although the button cell terminal (positive cell terminal) illustrated in the embodiment described above includes the stepped surface 15 in the compression force absorption spring section 13, the configuration of the terminal is not limited thereto. A modification of the positive cell terminal configuration is described below with reference to Fig. 4 described. In the following description, forming parts similar to or identical to those of the positive cell terminal 10 of the previously described embodiments are provided with the same reference numerals and are not described in detail.

[0029] As in Fig.As shown in Figure 4, the positive cell terminal 10a of the modification, similar to the positive cell terminal 10 described above, includes a pair of right and left spring contact terminals 11, a pair of right and left curved arms 14 having distal ends connected to the right and left spring contact terminals 11, respectively, and a curved piece 16 to which the rear ends of the right and left arms 14 are connected. In contrast to the positive cell terminal 10, the positive cell terminal 10 does not include the stepped surface 15, and a plate-like section, curved forward from the lower end of the curved piece 16, forms the plate connection 12a, which is connected to the circuit board 1.

[0030] Similar to the previously described positive cell terminal, the positive cell terminal 10a of the modification absorbs the pressing force from the button cell 2 (for example, impact load if the electrical equipment is dropped) with the spring contact terminals 11, which are in the form of a spring that deforms elastically according to the pressing force in the longitudinal and vertical directions of the button cell 2, and with the curved arm 14, which is also in the form of a spring that deforms elastically according to the pressing force in the longitudinal and transverse directions of the button cell 2. Since the positive cell terminal 10a does not include the stepped surface 15, the impact load is not distributed as it is with the stepped surface 15 in the positive cell terminal 10. As a result, the impact load from the battery or button cell 2 is exerted more strongly on the plate connection 12a, albeit slightly, compared to the positive cell terminal 10.

[0031] While one embodiment of the present disclosure is described above, this serves only for illustrative purposes, and the present invention is not limited to this embodiment and can be modified in various ways. For example, while in the configuration of the embodiment the positive cell terminal 10 is made of sheet metal as the button cell terminal, the configuration is not limited to this embodiment. The terminal can be made of any other material that has electrical conductivity (conductive materials).

Claims

[1] Button cell connector (10) for electrically connecting a printed circuit board (1) and a button cell (2), in which a direction along a plane direction of the button cell is defined as an X-axis direction, a direction along the plane direction perpendicular to the X-axis is defined as a Y-axis direction, and a direction perpendicular to the X-axis direction and to the Y-axis direction and along a thickness direction of the button cell is defined as a Z-axis direction, wherein the button cell connector has: a spring contact terminal (11) which is pressed through an outer circumferential surface (4a) of a positive electrode (4) of the button cell and is arranged in a spring shape which deforms elastically according to a pressing force exerted by the button cell in the X-axis direction and in the Z-axis direction; a plate connection (12) that is connected to the printed circuit board; and a pressing force absorption spring section (13) which is arranged between the plate connection and the spring contact terminal in order to be elastically deformable, and which absorbs the pressing force of the button cell which is received at the spring contact terminal by elastic deformation irrespective of the presence or absence of a cell holder which defines a position of the button cell, wherein the pressing force absorption spring section has a distal end section connected to the spring contact terminal and includes a curved arm (14) arranged in a spring shape which deforms elastically in accordance with the pressing force from the button cell in the X-axis direction and in the Y-axis direction in order to absorb the pressing force from the button cell, wherein the pressing force absorption spring section includes: a stepped surface (15) arranged in a stepped manner with respect to the plate connection; and a curved piece (16) which is bent in the Z-axis direction from a rear end of the stepped surface and perpendicular to the stepped surface, and which has a side section connected to a rear end of the bent arm. [2] Button cell connector according to claim 1, wherein: the spring contact terminal is arranged as a pair of spring contact terminals positioned in the Y-axis direction and is in contact with different parts of the outer circumferential surface of the positive electrode of the button cell; and The curved arm is arranged as a pair of curved arms positioned in the Y-axis direction to correspond to the pair of spring contact terminals. [3] Button cell connector according to one of claims 1 or 2, wherein the spring contact connector, the plate connection and the pressure force absorption spring section are configured as a single body with a conductive plate component.

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