Patent Description:
<CIT> proposes a bus bar in which a wiring pathway is formed of a single member made from a conductive material. The single member is formed in a shape along the wiring pathway by performing press working on a single flat plate shaped base material. Alternatively, the single member is formed in a shape along the wiring pathway by performing a forming process on a single linear base material.

Further prior art is known from documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

In the bus bar above in which a single member is processed to form a wiring pathway, when the wiring pathway is designed to be complicated, for example, manufacturing tolerances may be generated and thus the dimensional accuracy with respect to the wiring pathway may be reduced.

An object of the present invention is to provide a bus bar capable of improving the dimensional accuracy with respect to a wiring pathway.

A bus bar in accordance with the present invention includes the features of claim <NUM>.

According to the aforementioned configuration, it is possible to improve the dimensional accuracy with respect to a wiring pathway.

Various embodiments will be described hereinafter with reference to the accompanying drawings.

A detailed description will be hereinbelow provided for a bus bar <NUM> according to an embodiment by referring to the drawings. Noted that the proportions of the dimensions of the drawings are exaggerated for illustration purposes and therefore the proportions may be different from actual ones.

As illustrated in <FIG>, the bus bar <NUM> according to the embodiment is made from a conductive material and electrically connects between different battery stacks <NUM> mounted on a vehicle, for example. The bus bar <NUM> includes a wiring pathway <NUM> having bent portions <NUM> to avoid interference with non-illustrated peripheral members arranged between the battery stacks <NUM>. The wiring pathway <NUM> includes plate shaped members <NUM> consecutively arranged. The members <NUM> include connection members <NUM> and a conductive member <NUM>.

The connection members <NUM> include a first connection member <NUM> and a second connection member <NUM> arranged at both ends of the wiring pathway <NUM>. Connection portions <NUM> electrically connected to the battery stacks <NUM> are provided in the first connection member <NUM> and the second connection member <NUM>, respectively. The connection portions <NUM> are fastening portions to which non-illustrated fastening members such as bolts are fastened, for example.

The first connection member <NUM> and the second connection member <NUM> are made from copper which has excellent electrical connection to the battery stacks <NUM> and is suitable for fastening of the fastening members, for example. The first connection member <NUM> and the second connection member <NUM> may be made from copper alloy composed mainly of copper. The first connection member <NUM> and the second connection member <NUM> may be made from <NUM> series aluminum alloy composed mainly of aluminum which has excellent electrical connection to the battery stacks <NUM> and is suitable for fastening of the fastening members, for example. In this way, the material for the connection members <NUM> may be any materials as long as it has excellent conductivity and excellent stiffness.

The first connection member <NUM> and the second connection member <NUM> are respectively formed in a quadrangular plate shape by press working or a forming process. The first connection member <NUM> and the second connection member <NUM> are readily processable due to their simple quadrangular shape, thereby reducing the manufacturing cost. In the embodiment, the first connection member <NUM> and the second connection member <NUM> have the same plate thickness, the same plate width, and the same plate length. Thus, the first connection member <NUM> and the second connection member <NUM> can be formed by the same processing method, thereby reducing the manufacturing cost even more. The first connection member <NUM> and the second connection member <NUM> may be made from different materials and have different plate thicknesses, different plate widths, and different plate lengths. The conductive member <NUM> is arranged between the first connection member <NUM> and the second connection member <NUM>.

The conductive member <NUM> is arranged between the first connection member <NUM> and the second connection member <NUM> in the wiring pathway <NUM>. The conductive member <NUM> is made from copper as with the connection members <NUM>. The conductive member <NUM> may be made from copper alloy composed mainly of copper. When the connection members <NUM> are made from aluminum alloy composed mainly of aluminum, for example, the conductive member <NUM> may be made from the same aluminum alloy.

The conductive member <NUM> is formed in a quadrangular plate shape by press working or a forming process. The conductive member <NUM> is readily processable due to its simple quadrangular shape, thereby reducing the manufacturing cost. In the embodiment, the conductive member <NUM> and the connection members <NUM> have the same plate thickness, the same plate width, and the same plate length. Thus, the conductive member <NUM> and the connection members <NUM> can be formed by the same processing method, thereby reducing the manufacturing cost even more. The conductive member <NUM> and the connection members <NUM> may have different plate thicknesses, different plate widths, and different plate lengths. For example, the plate width of the conductive member <NUM> may be larger than the plate width of the respective connection members <NUM> in order to improve heat dissipation of the conductive member <NUM> with the increased surface area.

The conductive member <NUM> may be formed to have the bent portions <NUM> in the wiring pathway <NUM>. When the conductive member <NUM> is provided with the bent portions <NUM>, the conductive member <NUM> may be made from <NUM> series aluminum alloy composed mainly of aluminum which is softer than and superior in formability to the connection members <NUM>, for example. The plate thickness of the conductive member <NUM> may be less than the plate thickness of the connection members <NUM> in order to reduce the stiffness of the conductive member <NUM> with increased formability. In this way, the increased formability of the conductive member <NUM> allows processing for forming the bent portions <NUM> in the conductive member <NUM> to be easily carried out, thereby reducing the manufacturing cost.

The members <NUM> including the conductive member <NUM> and the connection members <NUM> described above are arranged along the wiring pathway <NUM> and the portions in contact with each other are connected to each other by laser joining. An example of the connection of the members <NUM> in the bus bar <NUM> is described below. First, as illustrated in <FIG>, the first connection member <NUM> and the second connection member <NUM> are arranged such that the positions of the connection portions <NUM> are fixed at prescribed positions. In this state, a connection surface <NUM> which is one end surface of the first connection member <NUM> in the width direction thereof and a connection surface <NUM> which is one end surface of the second connection member <NUM> in the length direction thereof are away from each other.

Next, as illustrated in <FIG>, the conductive member <NUM> is arranged such that a connection surface <NUM> which is one end surface of the conductive member <NUM> in the length direction thereof is in contact with the connection surface <NUM> of the first connection member <NUM>, and a connection surface <NUM> which is one end surface of the conductive member <NUM> in the width direction thereof is in contact with the connection surface <NUM> of the second connection member <NUM>. Then, the portions at which the connection surfaces <NUM>, <NUM> are located are connected to each other by laser joining, and the portions at which the connection surfaces <NUM>, <NUM> are located are connected to each other by laser joining. The connection of the first connection member <NUM>, the conductive member <NUM>, and the second connection member <NUM> forms the bent portions <NUM> in the wiring pathway <NUM>.

In this way, the wiring pathway <NUM> having the bent portions <NUM> can be formed by consecutively connecting the members <NUM> to each other by laser joining. Thus, there is no need to form a single member in a shape along the wiring pathway <NUM> by press working or a forming process and it is possible to easily correspond with wiring pathways <NUM> having various shapes. When the connection members <NUM> and the conductive member <NUM> are made from different types of metal such as copper and aluminum, an intermetallic compound may be generated at the connection portions thereof, causing the joint strength to decrease. Thus, when the connection members <NUM> and the conductive member <NUM> are made from different types of metal, a clad member including the same types of metal as the connection members <NUM> and the conductive member <NUM> may be interposed between the connection members <NUM> and the conductive member <NUM>.

In the bus bar <NUM> described above, the members <NUM> are arranged in the same plane. However, the present invention is not limited to this. For example, as illustrated in <FIG>, the members <NUM> may be arranged three-dimensionally and consecutively connected to each other by laser joining in order to correspond with the three-dimensional wiring pathway <NUM>. The bend angles at the bent portions <NUM> are not limited to <NUM> degrees. The bend angles at the bent portions <NUM> may be less than <NUM> degrees or more than <NUM> degrees in accordance with the bend shape of the wiring pathway <NUM>.

In the first connection member <NUM> and the second connection member <NUM> which are arranged at both ends of the wiring pathway <NUM>, the connection portions <NUM> need to be positioned to correspond to fixed points such as the different battery stacks <NUM>. However, when a single member is processed to form the wiring pathway <NUM> so as to be along the wiring pathway <NUM>, the positions of the connection portions <NUM> may be displaced due to manufacturing tolerances. For solving this problem, tolerance buffers <NUM> are provided in the connection portions of the members <NUM> in the embodiment.

In the tolerance buffer <NUM> at the connection portion of the first connection member <NUM> and the conductive member <NUM>, the width of the connection surface <NUM> of the first connection member <NUM> and the width of the connection surface <NUM> of the conductive member <NUM> are different from each other. The connection surface <NUM> of the first connection member <NUM> is the end surface facing the conductive member <NUM> in the width direction of the first connection member <NUM>, and includes the plate length of the first connection member <NUM>. The connection surface <NUM> of the conductive member <NUM> is the end surface facing the first connection member <NUM> in the length direction of the conductive member <NUM>, and includes the plate width of the conductive member <NUM>. In the tolerance buffer <NUM>, even when a tolerance is generated in the length direction of the first connection member <NUM>, the tolerance can be absorbed by moving the conductive member <NUM> in the length direction of the first connection member <NUM> with respect to the connection surface <NUM> of the first connection member <NUM>. The plate length of the first connection member <NUM> is equal to or longer than a prescribed length corresponding to the wiring pathway <NUM>. Thus, even if the conductive member <NUM> is arranged to the lower side in <FIG>, for example, a lack of room for connection of the connection surface <NUM> of the conductive member <NUM> to the connection surface <NUM> of the first connection member <NUM> is not caused, thereby enabling retention of the connection strength.

In the tolerance buffer <NUM> at the connection portion of the conductive member <NUM> and the second connection member <NUM>, the width of the connection surface <NUM> of the conductive member <NUM> and the width of the connection surface <NUM> of the second connection member <NUM> are different from each other. The connection surface <NUM> of the conductive member <NUM> is the end surface facing the second connection member <NUM> in the width direction of the conductive member <NUM>, and includes the plate length of the conductive member <NUM>. The connection surface <NUM> of the second connection member <NUM> is the end surface facing the conductive member <NUM> in the length direction of the second connection member <NUM>, and includes the plate width of the second connection member <NUM>. In the tolerance buffer <NUM>, even when a tolerance is generated in the width direction of the second connection member <NUM>, the tolerance can be absorbed by moving the conductive member <NUM> in the width direction of the second connection member <NUM> with respect to the connection surface <NUM> of the second connection member <NUM>. The plate length of the conductive member <NUM> is equal to or longer than a prescribed length corresponding to the wiring pathway <NUM>. Thus, even if the conductive member <NUM> is arranged to the left side in <FIG>, for example, a lack of room for connection of the connection surface <NUM> of the conductive member <NUM> to the connection surface <NUM> of the second connection member <NUM> is not caused, thereby enabling retention of the connection strength.

In the tolerance buffers <NUM> described above, the planar direction of the tolerance buffer <NUM> including the connection surfaces <NUM>, <NUM> and the planar direction of the tolerance buffer <NUM> including the connection surfaces <NUM>, <NUM> intersect one another. Specifically, the planar direction of the tolerance buffer <NUM> including the connection surfaces <NUM>, <NUM> and the planar direction of the tolerance buffer <NUM> including the connection surfaces <NUM>, <NUM> are mutually perpendicular. Intersection of the planar directions in the tolerance buffers <NUM> enables absorption of tolerances in the directions which intersect one another.

In this way, provision of the tolerance buffers <NUM> in the bus bar <NUM> enables absorption of manufacturing tolerances in the wiring pathway <NUM>. Thus, it is possible to correspond with wiring pathways <NUM> having various shapes without variation in the dimensional accuracy. Particularly, it is possible to retain the electrical connection reliability without displacement of the positions of the connection portions <NUM> of the connection members <NUM>.

Absorption of tolerances by the tolerance buffers <NUM> is not limited to a case where the members <NUM> are arranged in the same plane, and can be also applied to a case such as the bus bar <NUM> illustrated in <FIG> where the members <NUM> are arranged three-dimensionally. For example, in the bus bar <NUM> illustrated in <FIG>, the tolerance buffer <NUM> can be applied to the connection surface <NUM> of the first connection member <NUM> and the connection surface <NUM> of the conductive member <NUM> at the connection portion of the first connection member <NUM> and the conductive member <NUM>. The connection surface <NUM> of the first connection member <NUM> is the end surface facing the conductive member <NUM> in the plate thickness direction of the first connection member <NUM> (the lower surface in <FIG>), and includes the plate length of the first connection member <NUM>. The connection surface <NUM> of the conductive member <NUM> is the end surface facing the first connection member <NUM> in the length direction of the conductive member <NUM>, and includes the plate thickness of the conductive member <NUM>. In the tolerance buffer <NUM>, even when a tolerance is generated in the length direction of the first connection member <NUM>, the tolerance can be absorbed by moving the conductive member <NUM> in the length direction of the first connection member <NUM> with respect to the connection surface <NUM> of the first connection member <NUM>. Noted that a tolerance in the width direction of the first connection member <NUM> can be absorbed by the tolerance buffer <NUM> including the connection surfaces <NUM>, <NUM> in a case where the plate width of the conductive member <NUM> is larger than the plate width of the first connection member <NUM>.

The bus bar <NUM> described above includes the members <NUM> which are made from a conductive material and consecutively arranged to form a plate shape defining the wiring pathway <NUM>. The members <NUM> adjacent to each other are connected to each other by laser joining. The tolerance buffers <NUM> are provided between the members <NUM> adjacent to each other, and in each of the tolerance buffers <NUM> the connection surfaces of the members <NUM> adjacent to each other have different widths.

Thus, manufacturing tolerances generated when the wiring pathway <NUM> is formed with a single member can be absorbed by the tolerance buffers <NUM>. Accordingly, it is possible to improve the dimensional accuracy with respect to the wiring pathway <NUM> in the bus bar <NUM> described above.

The members <NUM> include at least three members <NUM>. The tolerance buffers <NUM> are provided in at least two sites between the members <NUM> adjacent to each other. The planar directions of the connection surfaces in the tolerance buffers <NUM> intersect one another. Thus, it is possible to absorb tolerances in the directions which intersect one another.

The planar directions of the connection surfaces in the tolerance buffers <NUM> are mutually perpendicular. Thus, it is possible to absorb tolerances in the directions which are mutually perpendicular.

The members <NUM> located at both ends of the wiring pathway <NUM> are the connection members <NUM> having the connection portions <NUM> for electrical input-output. Thus, absorption of tolerances by the tolerance buffers <NUM> enables retention of the electrical connection reliability without displacement of the positions of the connection portions <NUM>.

The connection portions <NUM> are the fastening portions to which the fastening members are fastened. Thus, absorption of tolerances by the tolerance buffers <NUM> enables stable fastening of the fastening members and thus retention of the electrical connection reliability without displacement of the positions of the connection portions <NUM> which correspond to the fixed points.

Claim 1:
A bus bar (<NUM>) comprising:
members (<NUM>) made from a conductive material and consecutively arranged to form a plate shape defining a wiring pathway (<NUM>), wherein
the members (<NUM>) adjacent to each other have a quadrangular plate shape and have connection surfaces (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the members (<NUM>) adjacent to each other being members laser joined at the connection surfaces (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>),
wherein surfaces having the connection surfaces (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) of the members (<NUM>) adjacent to each other have different widths and a plate length of one member (<NUM>) is equal to or longer than a prescribed length corresponding to the wiring pathway (<NUM>), this constitutes at least one tolerance buffer (<NUM>) between the members (<NUM>) adjacent to each other and the tolerance buffer (<NUM>) can absorb manufacturing tolerances,
wherein the bus bar (<NUM>) is formed according to the wiring pathway (<NUM>) having bent portions between the members (<NUM>) so forming a three dimensional wiring pathway,
the conductive members (<NUM>) include at least two connection members (<NUM>, <NUM>) and a conductive member (<NUM>),
the weld is across the end width of the connection members (<NUM>, <NUM>) to the length dimension of the connection members (<NUM>, <NUM>) at the bend, the connection members (<NUM>, <NUM>) effectively being made longer than necessary to provide the tolerance buffer (<NUM>) between the conductive member (<NUM>) and the connection members (<NUM>, <NUM>).