JP6894558B2 - Battery wiring module - Google Patents

Description

The present invention relates to a battery wiring module, and more particularly to short-circuit protection of wiring included in the battery wiring module.

In battery modules for electric vehicles and hybrid vehicles, a large number of cells are connected side by side in order to increase the output. By connecting the electrode terminals of adjacent cells with a connecting member such as a bus bar, a plurality of cells can be connected in series or in parallel. Here, when a plurality of single batteries are connected in series or in parallel, there is a problem that if the battery characteristics such as the battery voltage are not uniform among the single batteries, the batteries may be deteriorated or damaged.

Therefore, in the battery module for vehicles, in order to stop charging and discharging before the voltage between each cell becomes abnormal, a voltage detection line for detecting the voltage of the cell is attached to each connecting member. Has been done. The battery wiring module is composed of each connecting member and a voltage detection line (corresponding to wiring).

Since the voltage detection lines are generally connected to an external circuit such as a battery ECU, there is a risk that the two voltage detection lines will be short-circuited due to a defect in the external circuit. When the two voltage detection lines are short-circuited, the cell is short-circuited and the overcurrent continuously flows through the voltage detection lines. Therefore, it is known that a current limiting element such as a PTC (temperature coefficient of positive temperature) thermistor is connected in series to a voltage detection line formed on an FPC (flexible printed circuit board) (see Patent Document 1).

JP-A-2010-257775

In Patent Document 1, by providing a current limiting element on the voltage detection line, it is possible to prevent deterioration of the battery module due to a short circuit of the cell. However, when the vehicle is placed in a high humidity environment or the like, there is a possibility that dew condensation will occur on the FPC which constitutes the battery wiring module and is provided with the current limiting element.

When the FPC dewed, the electrodes on the cell side of any two of the plurality of current limiting elements provided on the FPC corresponding to each voltage detection line were formed due to the dew condensation. There was a risk of short circuit due to water droplets or the like. When the electrodes on the cell side of the two current limiting elements are short-circuited, the two voltage detection lines are short-circuited on the cell side of the current limiting element, and the current limiting element of the short-circuited voltage detection line functions. It disappears. Therefore, the overcurrent continuously flows from the cell to the short-circuited voltage detection line, and in this case, the voltage detection line cannot be protected from the overcurrent.
Therefore, the present specification provides a battery wiring module capable of protecting the voltage detection line from overcurrent in a configuration in which a current limiting element is connected in series in the middle of the voltage detection line provided in the FPC.

The battery wiring module disclosed by the present specification is a battery wiring module for a vehicle attached to a cell cell group in which a plurality of cell cells having positive and negative electrode terminals are arranged side by side, and the plurality of cell cells are described above. A flexible printed substrate having a plurality of connecting members connecting the positive and negative electrode terminals of the adjacent cell cells and a plurality of voltage detection lines for detecting the voltage of the plurality of cell cells via the plurality of connecting members. , And a current limiting element that limits the flow of overcurrent through the voltage detection line is provided in the middle of each voltage detection line, and the current limiting element is provided on the coverlay layer of the flexible printed substrate. Is arranged, and an opening for exposing the voltage detection line is formed at a position where the current limiting element is connected. The current limiting element is connected to the voltage detection line by solder, and the current The electrode of the current limiting element, which is the connection portion between the limiting element and the voltage detection line, the solder, and the exposed portion of the voltage detection line are overcoated with an insulating resin so as to cover the opening. Has been done.
According to this configuration, the connection portion between the current limiting element and the voltage detection line is overcoated with an insulating resin. Therefore, the electrodes on the cell side of any two of the plurality of current limiting elements provided on the FPC are not short-circuited by water droplets or the like formed due to dew condensation. Therefore, even if the FPC condenses, the two current limiting elements function, and in a configuration in which the current limiting elements are connected in series in the middle of the voltage detection lines provided in the FPC, the voltage detection lines are overcurrented. Can be protected from.

In the battery wiring module, the flexible printed circuit board is provided with a connection land for connecting the voltage detection line to the connection member, and the current limiting element is provided in the vicinity of the connection land. You may.
According to this configuration, the current limiting element is provided in the vicinity of the connecting land, that is, in the vicinity of the connecting member. Therefore, the length of the voltage detection line located between the current limiting element and the connecting member can be shortened. Thereby, the section between the current limiting element and the connecting member in which the two adjacent voltage detection lines are short-circuited can be shortened. As a result, the possibility that two adjacent voltage detection lines are short-circuited between the current limiting element and the connecting member can be reduced.
Here, "near the connection land" means, for example, between both ends of the connection member in the longitudinal direction (direction in which the cells are arranged).

Further, in the battery wiring module, each voltage detection line is wired so as to have a separated wiring portion that is separated from the other voltage detection lines, and the current limiting element is provided in each voltage detection line. It may be provided in the separated wiring portion.
According to this configuration, by providing the separate wiring portion, it becomes easy to install the current limiting element on the voltage detection line, and it is difficult to cause a short circuit between the installation portion of the current limiting element and another voltage detection line. Can be done.

Further, in the battery wiring module, the current limiting element may be configured by a positive temperature coefficient thermistor or a chip fuse.
According to this configuration, when an overcurrent flows through the voltage detection line, the resistance of the positive temperature coefficient thermistor increases or the chip fuse blows, thereby protecting the voltage detection line from the overcurrent. it can.

Further, the battery wiring module may be provided with a connector connected to the plurality of voltage detection lines and outputting the detected voltage of the single battery to the outside.
According to this configuration, by connecting the connector to an external circuit such as a battery ECU, charge / discharge control of a single battery can be easily performed.

According to the present invention, the voltage detection line can be protected from overcurrent in a configuration in which a current limiting element is connected in series in the middle of the voltage detection line provided in the FPC.

Schematic plan view of the battery module according to one embodiment Top view showing the battery wiring module Top view showing the battery wiring module Partially enlarged plan view showing the periphery of the current limiting element Sectional view taken along the line AA of FIG. Cross-sectional view showing the connection mode between the bus bar and the voltage detection line

<Embodiment>
One Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 6.

1. 1. Configuration of Battery Module The battery module 10 according to the present embodiment is used as a drive source for, for example, an electric vehicle or a hybrid vehicle. The battery module 10 is attached to a cell group 11G in which a plurality of (22 in this embodiment) cell cells 11 having a positive electrode terminal 13A and a negative electrode terminal 13B are arranged side by side, and the cell group 11G. The battery wiring module 20 is provided. In the following, the front shown in FIG. 1 is referred to as the front of the battery module 10, and the rear shown in FIG. 1 is referred to as the rear of the battery module 10. Further, the left side shown in FIG. 1 is the left side of the battery module 10, and the right side shown in FIG. 1 is the right side of the battery module 10.

A resin separator (not shown) is arranged between the two adjacent cells 11 and 11. The separator is provided with a protruding portion 15 which is formed to protrude. Each protrusion 15 is arranged in a space formed between two adjacent bus bars 21 and 21, and has a function of preventing a short circuit between electrodes due to a tool or the like.

2. Configuration of Battery Wiring Module The battery wiring module 20 includes a battery wiring module 20A attached to the front of the battery module 10 shown in FIG. 2 and a battery wiring module 20B attached to the rear of the battery module 10 shown in FIG. including. In the following description, when it is not necessary to distinguish between the battery wiring modules 20A and 20B, the battery wiring module 20A and 20B will be referred to as the battery wiring module 20.

The battery wiring module 20 includes a plurality of bus bars (an example of a “connecting member”) 21 and a flexible printed circuit board (hereinafter referred to as “FPC”) 25.

Each bus bar 21 connects the electrode terminals 13A and 13B of different cell batteries 11 to each other. Therefore, each bus bar 21 is formed with two terminal insertion holes 22 into which the electrode terminals 13A and 13B of different cell batteries 11 are inserted. As shown in FIG. 3, the connection members 21A at both ends of the battery wiring module 20B have one terminal insertion hole 22, and the connection member 21A at the right end is connected to the electrode terminal 13A, and the electrode terminal thereof. From 13A, a positive voltage which is the sum of the voltages of each cell 11 is applied to the load. On the other hand, the leftmost connecting member 21A is connected to the electrode terminal 13B, and the ground potential is applied to the load from the electrode terminal 13B.

The FPC 25 includes a plurality of voltage detection lines 26 that are connected to each bus bar 21 and detect the voltage of each unit cell 11. As shown in FIGS. 2 and 3, each voltage detection line 26 is provided with a current limiting element 27 that protects each voltage detection line 26 against continuous overcurrent. The current limiting element 27 is a PTC (positive temperature coefficient) thermistor or a chip fuse.

Specifically, the copper foil formed on the base layer 25A of the FPC 25 is patterned to form the voltage detection line 26 shown in FIGS. 2 and 3. At the time of patterning, as shown in FIG. 5, the copper foil at the position where the current limiting element 27 is connected is deleted. That is, the current limiting element 27 is connected in series with the voltage detection line 26 in the middle of the voltage detection line 26.

Further, as shown in FIGS. 2 and 3, each voltage detection line 26 is wired, that is, patterned so as to have a separated wiring portion 26A separated and wired from the other voltage detection lines 26. The current limiting element 27 is provided in the separate wiring portion 26A in each voltage detection line 26.

Further, as shown in FIGS. 4 and 5, a rectangular opening W is formed in the coverlay layer 25B of the FPC 25 where the current limiting element 27 is connected. The opening W exposes the voltage detection line 26 at the location where the current limiting element 27 is connected. Then, the electrode (connection portion) 27A of the current limiting element 27 is joined to the exposed voltage detection line 26 by, for example, a solder SD.

In this way, the current limiting element 27 is connected in series to the voltage detection line 26 in the middle of the voltage detection line 26. As a result, when the two voltage detection lines 26 are short-circuited due to a defect in an external circuit such as a battery ECU to which the battery wiring module 20 is connected, and an overcurrent from a single battery occurs in the voltage detection line 26 Even so, it is possible to limit the flow of the overcurrent from the cell 11 to the voltage detection line 26 to the voltage detection line 26.

For example, when the current limiting element 27 is a PTC thermistor, when an overcurrent flows through the voltage detection line, the resistance of the PTC thermistor increases as the temperature of the voltage detection line 26 rises, and the flow of the overcurrent can be restricted. .. Further, when the current limiting element 27 is a chip fuse, when an overcurrent flows through the voltage detection line 26, the chip fuse blows, so that the overcurrent can be restricted from flowing.

As a result, the voltage detection line 26 can be protected even when an overcurrent occurs in the voltage detection line 26 provided in the FPC 25 due to a defect in the external circuit.

Further, as shown in FIGS. 4 and 5, the portion to which the current limiting element 27 is connected is overcoated with the insulating resin 23 so as to cover the opening W. That is, the connection portion between the current limiting element 27 and the voltage detection line 26 is overcoated with an insulating resin. Here, the connection portion includes the electrode 27A of the current limiting element 27, the solder SD, and the exposed portion of the voltage detection line 26.

Further, a connection land 28 electrically connected to the bus bar 21 is formed at one end of each voltage detection line 26. The current limiting element 27 is provided near the connecting land 28.

Specifically, as shown in FIG. 6, the connection land 28 is composed of a copper foil on the convex portion 25C of the base layer 25A of the FPC 25, and the voltage detection line 26 and the connection land 28 are continuous. Further, the coverlay layer 25B is not formed in the region where the connection land 28 is formed (convex portion 25C), and the connection land 28 is exposed. The connection land 28 and the bus bar 21 are joined by, for example, a solder SD. In this way, when connecting the bus bar 21 to the upper surface of the connecting land 28, the work for connecting the bus bar 21 to the connecting land 28 is simpler than when connecting the bus bar 21 to the lower surface of the connecting land 28. Be made.

That is, when the bus bar 21 is connected to the upper surface of the connection land 28, the solder surface with respect to the copper foil for connecting the current limiting element 27 to the voltage detection line 26 is on the same side. On the other hand, when the bus bar 21 is connected to the lower surface of the connection land 28, the solder surface with respect to the copper foil is different when the current limiting element 27 is connected to the voltage detection line 26 and when the bus bar 21 is connected. Therefore, the soldering work becomes complicated.

Further, when the bus bar 21 is connected to the lower surface of the connecting land 28, it is necessary to peel off the base layer 25A from the copper foil when exposing the connecting land 28, which takes time and effort to expose the connecting land 28.
Each connection portion between the connection land 28 and the bus bar 21 may be overcoated with the insulating resin 23 in the same manner as the connection portion between the current limiting element 27 and the voltage detection line 26.

The other end of each voltage detection line 26 is connected to the connector 29. The connector 29 is connected to a battery ECU (not shown). The battery ECU is equipped with a microcomputer, a circuit element, etc., and has a function for detecting the voltage, current, temperature, etc. of each cell 11 and controlling charge / discharge of each cell 11. It has a well-known configuration.

3. 3. Effect of Embodiment The connection portion between the current limiting element 27 and the voltage detection line 26 is overcoated with the insulating resin 23. Therefore, the electrodes 27A on the unit cell side of any two of the plurality of current limiting elements 27 provided in the FPC 25 are not short-circuited by water droplets formed due to dew condensation or the like. Therefore, even when the FPC 25 is dewed, each current limiting element 27 functions normally, and in a configuration in which the current limiting element 27 is connected in series in the middle of the voltage detecting line 26 provided in the FPC 25, the voltage detecting line 26 can be protected from overcurrent.

Further, the current limiting element 27 is provided in the vicinity of the connection land 28, that is, in the vicinity of the bus bar 21. Therefore, the length of the voltage detection line 26 located between the current limiting element 27 and the bus bar 21 can be shortened. As a result, the section between the current limiting element 27 and the bus bar 21 where the two adjacent voltage detection lines 26 are short-circuited can be shortened. As a result, it is possible to reduce the possibility that two adjacent voltage detection lines 26 are short-circuited between the current limiting element 27 and the bus bar 21, in other words, on the cell 11 side of the current limiting element 27.

Here, "near the connection land 28" means, for example, between both ends of the bus bar 21 in the longitudinal direction (the direction in which the cells 11 are arranged, that is, the left-right direction in FIG. 1), in other words, the connection land 28 and the bus bar 21. Means between one end in the longitudinal direction of. In this case, not all current limiting elements 27 are provided between both ends of the bus bar 21. Of all the current limiting elements 27, for example, a current limiting element 27 of 50% or more, 75% or more, or 90% or more may be provided between both ends of the bus bar 21.

Further, each voltage detection line 26 is wired so as to have a separate wiring portion 26A separated from the other voltage detection lines 26, and the current limiting element 27 is a separate wiring portion 26A in each voltage detection line 26. It is provided in. Therefore, the current limiting element 27 can be easily installed on the voltage detection line 26, and a short circuit between the current limiting element 27 and the other voltage detection line 26 can be made less likely to occur.

<Other Embodiments>
The present invention is not limited to the embodiments described in the above description and drawings, and for example, the following embodiments are also included in the technical scope of the present invention.
(1) In the present embodiment, in the connection between the FPC 25 and the bus bar 21, as shown in FIG. 6 and the like, the configuration in which the bus bar 21 is connected to the upper side of the FPC 25 is shown, but the present invention is not limited to this. On the contrary, the bus bar 21 may be connected to the lower side of the FPC 25. At that time, the FPC 25 may be turned upside down to connect the bus bar 21 so that the base layer 25A of the FPC 25 is on the upper side and the coverlay layer 25B is on the lower side.
Further, the connection mode between the FPC 25 and the bus bar 21 is not limited to the electrical connection land 28 as shown in FIG. 6 and the like. In addition, the FPC 25 and the bus bar 21 may be provided with a mechanical connection portion that reinforces the connection by the connection land 28 only.

(2) In the present embodiment, as shown in FIG. 1, an example is shown in which the battery wiring module is separated into the front battery wiring module 20A and the rear battery wiring module 20B, but the present invention is limited to this. I can't. That is, the battery wiring module may not be separated into the battery wiring module 20A and the battery wiring module 20B. For example, a connection portion for connecting the battery wiring module 20A and the battery wiring module 20B may be provided, and the battery wiring module and the battery ECU may be connected by one connector.

(3) The FPC 25 may be formed with a predetermined amount of deflection (margin in the arrangement direction of the cell 11) at positions at predetermined intervals, for example, at positions between the bus bars 21. In this case, when the battery wiring module 20 is mounted on the cell group 11G, the tolerance of the size of the cell 11 can be accommodated. That is, even if there is a difference in the size of the cells 11 in the arrangement direction, the difference can be absorbed by a predetermined amount of deflection. Thereby, the work when the battery wiring module 20 is mounted on the cell group 11G can be simplified. In addition, the stress applied to the FPC 25 due to the size tolerance of the battery 11 can be absorbed. That is, the reliability of the battery wiring module 20 can be improved.

11 ... Single battery 11G ... Single battery group 13A ... Positive electrode terminal 13B ... Negative electrode terminal 20, 20A, 20B ... Battery wiring module 21 ... Bus bar (connecting member)
23 ... Insulation resin 25 ... FPC (Flexible printed circuit board)
26 ... Voltage detection line 27 ... Current limiting element 27A ... Current limiting element electrode 28 ... Connection land

Claims (5)

A battery wiring module for a vehicle that is attached to a cell group in which a plurality of cell cells having positive and negative electrode terminals are arranged side by side.
A plurality of connecting members for connecting the electrode terminals of the positive electrode and the negative electrode of the adjacent cell cells of the plurality of cell cells, and
A flexible printed circuit board having a plurality of voltage detection lines for detecting the voltage of the plurality of cells via the plurality of connecting members.
In the middle of each voltage detection line, a current limiting element that limits the flow of overcurrent through the voltage detection line is provided.
The current limiting element is arranged in the coverlay layer of the flexible printed circuit board, and an opening for exposing the voltage detection line at a position to which the current limiting element is connected is formed.
The current limiting element is connected to the voltage detection line by solder.
The electrode of the current limiting element, which is the connection portion between the current limiting element and the voltage detection line, the solder, and the exposed portion of the voltage detection line are provided with an insulating resin so as to cover the opening. Overcoated battery wiring module. In the battery wiring module according to claim 1,
A battery wiring module which is connected to the plurality of voltage detection lines, outputs the detected voltage of the cell to the outside, and has a plurality of connectors derived in different directions from each other. In the battery wiring module according to claim 2.
The connector is a battery wiring module that is led out in a direction that intersects with a direction in which the flexible printed circuit board extends. In the battery wiring module according to any one of claims 1 to 3.
Each voltage detection line is wired so as to have a separate wiring portion that is separated and wired from the other voltage detection lines.
The current limiting element is a battery wiring module provided in the separated wiring portion in each voltage detection line. In the battery wiring module according to any one of claims 1 to 4.
The current limiting element is a battery wiring module which is a positive temperature coefficient thermistor or a chip fuse.

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