JP2010157399A - Battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery module capable of accurately detecting a cell voltage. <P>SOLUTION: The battery module includes a plurality of battery cells, electrodes provided in the individual battery cells, electrode terminals 13 projected from the surface of the respective electrodes, a control unit for detecting and controlling the voltage of each battery cell, and a flexible printed circuit board for connecting the control unit and the battery cells. The flexible printed circuit board is directly connected to the electrode terminals 13, and connections 31 for connecting the flexible printed circuit board and each electrode terminal 13 is fixed by a fixing member 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery module.

In a vehicle battery module, a high voltage is obtained by connecting a large number of battery cells in series in order to increase the output. When a plurality of battery cells are connected in series, if battery characteristics such as battery voltage are not uniform between the battery cells, there is a problem in that the battery is overdischarged or overcharged, leading to deterioration or breakage of the battery. Therefore, the battery module for vehicles is provided with a control unit that detects the voltage of each battery cell and stops charging and discharging before the battery module is overdischarged or overcharged. A terminal for detecting a cell voltage connected to the battery cell (referred to as “voltage detection terminal”) is connected to the control unit.
As a structure for connecting the voltage detection terminal as described above to a battery cell, for example, the structure described in Patent Document 1 is known.
JP 2000-333343 A

  Patent Document 1 has a structure in which a voltage detection terminal is provided for every two adjacent battery cells, and each electrode of the battery cell is connected to the bus bar by tightening a nut, and the voltage detection terminal is connected via the bus bar. The structure is described.

  In the structure described in Patent Document 1, since the bus bar is interposed between the battery cell and the voltage detection terminal, the resistance value of the connection portion between the battery cell and the voltage detection terminal is increased. In addition, since one voltage detection terminal is provided for two battery cells, the resistance value at the connection between the voltage detection terminal and the electrode is higher than when a voltage detection terminal is provided for each battery cell. Tend to be. Thus, when the resistance value of the connection part of a battery cell and a voltage detection terminal becomes high, there exists a problem that a highly accurate voltage detection cannot be performed.

Also, depending on the type of battery used, a maximum current of 100 mA may flow to adjust the capacity of the battery cell. If the resistance value at the connection between the voltage detection terminal and the electrode is high, accurate voltage detection cannot be performed. It is necessary to keep the value low.
This invention is completed based on the above situations, Comprising: It aims at providing the battery module which can detect a cell voltage with high precision.

  The present invention includes a plurality of battery cells, an electrode provided in the battery cell, an electrode terminal provided protruding from the surface of the electrode, a control unit that detects and controls the voltage of the battery cell, A flexible printed circuit board that connects the control unit and the battery cell, the flexible printed circuit board is directly connected to the electrode terminal, and the connection part between the flexible printed circuit board and the electrode terminal is fixed by a fixing member It is fixed.

  In the battery module of the present invention, the flexible printed circuit board that connects the control unit that controls the cell voltage of each battery cell and the electrode terminal is directly connected to the electrode terminal, so the connection unit between the flexible printed circuit board and the electrode terminal Resistance can be reduced. Moreover, since the connection part of a flexible printed circuit board and an electrode terminal is fixed by a fixing member, the electrical connection of an electrode terminal and a flexible printed circuit board can be made reliable. As a result, according to the present invention, a battery module capable of detecting a cell voltage with high accuracy can be provided.

The present invention may have the following configuration.
The flexible printed circuit board may be provided with an electrode insertion hole smaller than the outer periphery of the electrode terminal and a slit formed in the outer peripheral direction of the flexible printed circuit board from a hole wall of the electrode insertion hole. Good.
Since the electrode insertion hole of the flexible printed circuit board with the above configuration is smaller than the electrode terminal, when the electrode terminal is inserted into the electrode insertion hole, the electrode terminal is expanded while expanding the slit formed in the outer peripheral direction from the hole wall of the electrode insertion hole. It is inserted. And since the flexible printed circuit board is arranged along the side wall surface of the electrode terminal in the state where the operation of inserting the electrode terminal into the electrode insertion hole is completed, according to the above configuration, the contact between the electrode terminal and the flexible printed circuit board The area is increased, and the resistance at the connection portion can be further reduced.

  In the said structure, it is preferable to set it as the aspect by which the flexible printed circuit board is provided with two or more slits and the crease | fold which connects adjacent slits is formed. It is preferable to insert the electrode terminal through a flexible printed circuit board that has been folded along the crease in advance, because the working efficiency is improved and the flexible printed circuit board and the side surface of the electrode terminal are easily brought into contact with each other.

It is good also as a structure provided with the joint terminal which electrically connects the said electrode terminal provided in the said battery cell, and the electrode terminal provided in another battery cell adjacent to the said battery cell.
This configuration is preferable because it can save time and labor for connecting the electrode terminals of adjacent battery cells.

A bus bar is provided for electrically connecting the electrode terminal provided in the battery cell and an electrode terminal provided in another battery cell adjacent to the battery cell, and the bus bar is fixed to the electrode terminal. It is good also as a structure in which the screw thread which screws the screw member to perform and the level | step difference surface which mounts the said bus-bar or the said flexible printed circuit board are formed.
According to the said structure, this invention is applicable also to the thing of a structure provided with a bus-bar by forming a level | step difference surface and a screw thread in an electrode terminal.

  According to the present invention, a battery module capable of detecting a cell voltage with high accuracy can be provided.

<Embodiment 1>
Hereinafter, Embodiment 1 which actualized this invention is demonstrated in detail, referring FIGS. 1-7.
As shown in FIG. 1, the battery module 1 of the present embodiment includes a plurality of battery cells 10 and a battery ECU (Electronic Control Unit; corresponding to the control unit of the present invention, not shown) that controls each battery cell 10. And a flexible printed circuit board 20 (hereinafter abbreviated as FPC 20) for connecting each battery cell 10 and the battery ECU.

  The battery ECU is equipped with a microcomputer, an element, etc. (not shown), and has a well-known configuration having functions for detecting cell voltage, current, temperature, etc., charging / discharging control of each battery cell 10 and the like. belongs to. The battery ECU is connected to each battery cell 10 by an FPC 20 (details will be described later).

A plurality of battery cells 10 are arranged in such a manner that adjacent battery cells 10 are opposite to each other. These battery cells 10 are fixed by the holding plate 2.
The battery cell 10 has a known configuration used as a drive source for an electric vehicle or a hybrid vehicle, for example. The battery cell 10 is formed in a cylindrical shape as a whole, and includes a main body 11 in which a power generation element (not shown) is accommodated, and a pair of positive and negative electrodes 12 provided on one end surface and the other end surface of the main body 11. It has. Electrode terminals 13 are respectively provided on the surface of the electrode 12 so as to protrude vertically, and the adjacent electrode terminals 13 are electrically connected by a joint terminal 3 as shown in FIG.

  The joint terminal 3 is formed by, for example, pressing a metal plate material such as copper, copper alloy, stainless steel (SUS) into a predetermined shape. The joint terminal 3 includes electrode connection portions 4A and 4B connected to the positive and negative electrode terminals 13 of the battery cells 10 adjacent in the short side direction of the holding plate 2, respectively. In the following description, the first electrode connection portion disposed on the right side in FIG. 1 is referred to as 4A, and the second electrode connection portion 4B disposed on the left side.

  Each of the two electrode connecting portions 4A and 4B is substantially U-shaped, and has a pair of opposing walls 5 that can be elastically displaced in the approaching / separating direction (opposing direction). Each opposing wall 5 has a substantially rectangular plate shape that is long in a direction substantially orthogonal to the connection direction with respect to the electrode terminal 13. A pair of opposing walls 5 are connected to each other at both ends in the left-right direction shown in FIG. 1, and each opposing wall 5 is cantilevered in the same direction from each other's connecting portion (hereinafter referred to as a bent portion 6). It has a form that extends into a shape. The distance between the pair of opposing walls 5 in the natural state is set to be smaller than the maximum width dimension of the electrode terminal 13, and comes into elastic contact with the electrode terminal 13 when connected to the electrode terminal 13. Yes.

The two electrode connection portions 4A and 4B have substantially the same shape and the same size, and the first electrode connection portion 4A and the second electrode connection portion 4B are opposite in the left-right direction shown in FIG. They are connected to each other via the connecting portion 7 in a posture.
One opposing wall 5 of the pair of opposing walls 5 of each electrode connecting portion 4A, 4B is connected to the connecting portion 7. The opposing walls 5 of the electrode connecting portions 4A and 4B are connected to approximately half of the lengths of both edges extending in the longitudinal direction of the connecting portion 7, respectively. In addition, the bending part 6 of each electrode connection part 4A, 4B and the other opposing wall 5 are not connected with the connection part 7, but are in a free state.

  The electrode terminal 13 is made of metal (copper, copper alloy, aluminum, aluminum alloy, etc.), and is formed to have substantially the same shape and size by a known method such as pressing, cutting, casting, or forging. (See FIGS. 2 and 4). A spherical head 14A is provided at the tip of each electrode terminal 13.

  As shown in FIG. 5, the electrode terminal 13 of the present embodiment is constricted immediately below the spherical head 14 </ b> A (the surface side of the electrode 12) and is more constricted than the constricted part (referred to as “constricted part 14 </ b> B”) Furthermore, the lower side has a cylindrical shape (referred to as “cylindrical portion 14C”) having a diameter larger than that of the head portion 14A. An FPC 20 is connected to the cylindrical portion 14 </ b> C of the electrode terminal 13. A connection portion 31 (corresponding to the connection portion 31 of the present invention, hereinafter also referred to as “connection portion 31”) between the electrode terminal 13 and the FPC 20 is C-shaped. A metal clamp 30 (corresponding to the fixing member 30 of the present invention) is attached.

  In the present embodiment, as shown in FIGS. 2 and 3, the two FPCs 20 are arranged substantially parallel to the longitudinal direction of the holding plate 2. The FPC 20 has a configuration in which a circuit is formed by a copper conductor foil 21B on an insulating base film 21A, and the upper surface of the conductor foil 21B is covered with a protective film 21C. As the base film 21A and the protective film 21C of the FPC 20, those made of polyimide can be used, respectively.

  The FPC 20 includes a strip-shaped base portion 22 disposed substantially parallel to the longitudinal direction of the holding plate 2, and projects along the width direction of the base portion 22 from the side edge on the long side of the base portion 22. A circular connection piece 23 connected to the electrode terminal 13 and a semicircular positioning piece 24 fixed by a positioning pin 32 are provided.

The base portion 22 is formed in a strip shape that is narrower than the distance between the two battery cells 10 rows, and is laid between the battery cells 10 rows on the outer surface of the holding plate 2. ing.
A positioning hole 24A through which the positioning pin 32 can be inserted is formed in the semicircular positioning piece 24 protruding from the base portion 22.

  As shown in FIG. 4, the circular connection piece 23 protruding from the base portion 22 is arranged at a position corresponding to the electrode terminal 13 of each battery cell 10 and is directly connected to the electrode terminal 13. As shown in FIGS. 6 and 7, a circular electrode insertion hole 25 set smaller than the outer periphery of the head portion 14 </ b> A of the electrode terminal 13 is provided in the center of the connection piece 23.

On the lower surface of the connection piece 23 (surface on the side connected to the electrode terminal 13), between the hole edge region 25 </ b> A including the hole edge portion of the electrode insertion hole 25 and the peripheral region 23 </ b> A including the outer periphery of the connection piece 23. In the annular region 31A, a part of the conductive foil 21B is exposed by removing a part of the protective film 21C (see FIG. 6). In FIG. 6, the connection pieces 23 are schematically shown by shading the areas 25 </ b> A and 23 </ b> A covered with the protective film 21 </ b> C.
An annular region 31A from which the conductive foil 21B is exposed (hereinafter also simply referred to as “annular region 31A”) is a region 31A that is electrically connected to the cylindrical portion 14C of the electrode terminal 13, and detects the voltage of the battery cell 10. Functions as a voltage detection terminal.
As shown in FIG. 7, the upper surface of the connection piece 23 (the surface opposite to the surface connected to the electrode terminal 13) is covered with the base film 21A over the entire area. In FIG. 7, the area covered with the base film 21 </ b> A is shaded.

  In the connection piece 23, a slit 26 is formed from the hole wall 25 </ b> B of the electrode insertion hole 25 toward the outer peripheral edge of the connection piece 23. Seven slits 26 are formed at equal intervals starting from the hole wall 25B of the electrode insertion hole 25 and starting from the outer periphery of the annular region 31A where the conductor foil 21B is exposed.

For example, the connection / fixing operation of the FPC 20 to the electrode terminal 13 is performed as follows.
When the FPC 20 is arranged so that the surface where the annular region 31A is formed is on the lower side and the head portion 14A of the electrode terminal 13 is inserted into the electrode insertion hole 25 provided in the connection piece 23, the electrode insertion hole 25 becomes an electrode. Since it is set smaller than the outer periphery of the head portion 14A of the terminal 13, the electrode terminal 13 is inserted into the electrode insertion hole 25 while expanding the slit 26 provided in the hole wall 25B of the electrode insertion hole 25. When the operation of inserting the electrode terminal 13 into the electrode insertion hole 25 is completed, the connection piece 23 is arranged along the side wall surface of the cylindrical portion 14 </ b> C of the electrode terminal 13. Next, the clamp 30 is attached to the outer side of the connection piece 23 arranged along the side wall surface of the electrode terminal 13, and the connection part 31 of the connection piece 23 and the electrode terminal 13 is fixed (refer FIG. 5).

  In this embodiment, after connecting and fixing the FPC 20 to the electrode terminal 13, the joint terminal 3 is pushed into the battery cell 10 side so that the electrode terminal 13 is inserted between the opposing walls 5 of the electrode connection portions 4A and 4B. Thus, the adjacent electrode terminals 13 are electrically connected (see FIGS. 1 and 5).

  According to this embodiment, since the connection piece 23 of the FPC 20 that connects the battery ECU (control unit) that controls the cell voltage of each battery cell 10 and the electrode terminal 13 is directly connected to the electrode terminal 13, the FPC 20 The resistance of the connection part 31 with the electrode terminal 13 can be lowered. In particular, in the present embodiment, the electrode insertion hole 25 smaller than the outer periphery of the electrode terminal 13 is provided in the FPC 20, and the slit 26 is formed in the hole wall 25B of the electrode insertion hole 25. The contact area between the electrode terminal 13 through which 25 is inserted and the connection piece 23 of the FPC 20 is increased, and the resistance at the connection portion 31 between the FPC 20 and the electrode terminal 13 can be further suppressed. Further, according to the present embodiment, since the connection portion 31 between the FPC 20 and the electrode terminal 13 is fixed by the clamp 30, the electrical connection between the electrode terminal 13 and the FPC 20 can be ensured. As a result, according to the present embodiment, it is possible to provide the battery module 1 capable of detecting the cell voltage with high accuracy.

  Furthermore, according to this embodiment, since the joint terminal 3 which electrically connects between the adjacent electrode terminals 13 is provided, the effort concerning the connection work of the electrode terminals 13 of the adjacent battery cells 10 can be saved.

  Moreover, as above-mentioned, one of the pair of opposing walls 5 of the joint terminal 3 used in this embodiment is mutually connected in the left-right direction. Thereby, it can set so that the elastic force required in order to pinch | interpose the electrode terminal 13 elastically can be provided by making a pair of opposing wall 5 long in the left-right direction. Here, for example, when the upper ends of the pair of opposing walls 5 are connected to each other, if the same setting is to be made, the opposing walls 5 must be elongated in the vertical direction (connection direction). There is a possibility that 3 will be enlarged in the vertical direction. When the joint terminal 3 increases in size in the vertical direction, the vertical dimension of the battery module 1 (the dimension in the axial direction of the battery cell 10) increases accordingly, that is, the battery module 1 increases in size. However, in the present embodiment, the pair of opposing walls 5 can be set to have the necessary elastic force by elongating in the left-right direction. Therefore, the enlargement of the battery module 1 can be prevented.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIG.
The battery module 1 according to the present embodiment is different from the first embodiment in that the battery module 1 includes a stepped electrode terminal 13 and a bus bar 40. In addition, the same code | symbol is attached | subjected to the structure similar to Embodiment 1, and the overlapping description is abbreviate | omitted.
As shown in FIG. 10, the electrode terminal 13 of the present embodiment has a flat upper end surface, and a cylindrical thread portion 16 in which a thread 15 capable of screwing a screw member such as a nut 42 is formed on the side surface. And a disc-shaped disc portion 17 formed below the screw portion 16.

In the present embodiment, the electrode terminal 13 has a stepped structure by setting the diameter of the screw portion 16 to be smaller than the diameter of the disk portion 17, and the upper surface 18 of the disk portion 17 of the electrode terminal 13 is the step surface 18 of the present invention. It corresponds to.
The disk portion 17 of the electrode terminal 13 is connected to the connection piece 23 of the FPC 20 on its side surface, and the bus bar 40 is placed on the upper surface 18 of the disk portion 17.
The bus bar 40 is fixed to the electrode terminal 13 by tightening a nut 42 by inserting a screw hole 41 provided in the bus bar 40 into the screw portion 16 of the electrode terminal 13.
The bus bar 40 is formed of a metal in a plate shape, and electrically connects the adjacent electrode terminals 13.

Also in the present embodiment, the connection piece 23 of the FPC 20 is directly connected to the electrode terminal 13 and the connection portion 31 between the FPC 20 and the electrode terminal 13 is fixed by the clamp 30 as in the first embodiment. The battery module 1 capable of accurately detecting the cell voltage can be provided.
Further, according to the present embodiment, the present invention can be applied to a structure having the bus bar 40 by forming the step surface 18 and the screw thread 15 on the electrode terminal 13.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the FPC 20 including the connecting piece 23 provided with the seven slits 26 starting from the hole wall of the electrode insertion hole 25 and starting from the outer peripheral edge of the annular region 31A is shown. The thing and the number of the slits 26 may be other than seven. Specifically, as shown in FIG. 8, the slit 26 may be provided from the hole wall 25B of the electrode insertion hole 25 to a position extending from the annular region 31A to a region outside the annular region 31A.
In the above embodiment, the FPC 20 including the connecting piece 23 in which the fold line 27 that connects the slits 26 is not formed is shown. However, as shown in FIG. 8, the fold line 27 that connects the adjacent slits 26 is formed. It may be. When the FPC 20 having the connection piece 23 configured as shown in FIG. 8 is used, the work efficiency is improved by inserting the electrode terminal 13 through the connection piece 23 previously folded along the fold line 27. This is preferable because the connection piece 23 can be easily brought into contact with the side surface of the electrode terminal 13.
In FIG. 8, similarly to FIG. 6, the connection pieces 23 are schematically shown by shading the regions 25 </ b> A and 23 </ b> A covered with the protective film 21 </ b> C.

(2) Although the electrode terminal 13 including the spherical head portion 14A, the constricted portion 14B, and the cylindrical portion 14C is shown in the first embodiment, the shape of the electrode terminal 13 is not limited to this.
Specifically, the electrode terminal 13 has a cylindrical shape having a constant diameter, a head portion 14A that is not spherical, or a cylindrical portion that is smaller in diameter than the head portion 14A just below the spherical head portion 14A. It may have a continuous shape, a shape shown in FIG.
The electrode terminal 13 shown in FIG. 9 has a structure in which a cylindrical portion 14C is connected immediately below a spherical head portion 14A, and a protrusion 14D protruding from the cylindrical portion 14C is formed at a position slightly above the lower end of the cylindrical portion 14C. belongs to.
9 having the electrode terminal 13 as shown in FIG. 9 is preferable because the protrusion 14D provided on the cylindrical portion 14C of the electrode terminal 13 functions as positioning of the FPC 20 and prevents the fixing member 30 from shifting downward. .

  (3) In the first embodiment, the joint terminal 3 having a pair of opposing walls 5 set so as to be in elastic contact with the electrode terminal 13 is shown. However, the spherical surface of the electrode terminal 13 is provided on the opposing wall 5. It may be a joint terminal having a structure provided with a hole for fitting.

(4) In the second embodiment, the electrode terminal 13 has a stepped structure by providing the disk portion 17 having a diameter larger than that of the screw portion 16, but the electrode terminal 13 having the stepped structure is as shown in FIG. A structure may be used.
The electrode terminal 13 shown in FIG. 11 has a structure in which a disk-shaped portion 19 having a diameter smaller than that of the screw portion 16 overlaps with the screw portion 16 in which the screw thread 15 is formed. By setting the diameter of the disk-shaped portion 19 of the electrode terminal 13 to be smaller than the diameter of the threaded portion 16, the electrode terminal 13 has a stepped structure, and the upper surface 16A of the threaded portion 16 is a stepped surface.
In the battery module 1 including such an electrode terminal 13, the bus bar 40 is placed on the surface of the electrode 12 by inserting a screw hole provided in the bus bar 40 into the screw portion 16 of the electrode terminal 13, and tightened with a nut 42. It is fixed to the electrode terminal 13. The FPC 20 is placed on the upper surface 16 </ b> A of the screw portion 16 of the electrode terminal 13, and the connection piece 23 of the FPC 20 is connected to the side surface of the disk-shaped portion 19.

  (5) In the above embodiment, one C-shaped clamp 30 is used as the fixing member 30 for fixing the connecting portion 31 between the FPC 20 and the electrode terminal 13, but it may be fixed by two or more clamps 30. Instead of the clamp 30, or together with the clamp 30, an elastic fixing member such as a metal clip may be used.

The perspective view which shows the battery module of Embodiment 1. FIG. The perspective view which shows the battery module of the state which does not connect a joint terminal Plan view showing the battery module without the joint terminal connected The perspective view which shows the state by which FPC was connected to the electrode terminal Side sectional view showing the connection relationship between joint terminals and electrode terminals Schematic showing the surface connected to the electrode terminals of the FPC connection piece The schematic diagram which showed the surface on the opposite side to the connection surface with the electrode terminal of the connection piece of FPC The schematic diagram which showed the surface connected with the electrode terminal of the connection piece of FPC demonstrated in other embodiment (1). Sectional drawing which showed the connection structure of the electrode terminal and FPC demonstrated in other embodiment (2) Sectional drawing which showed the connection structure of the electrode terminal and FPC which were used for the battery module of Embodiment 2. Sectional drawing which showed the connection structure of the electrode terminal demonstrated by other embodiment (4), and FPC

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery module 10 ... Battery cell 12 ... Electrode 13 ... Electrode terminal 20 ... Flexible printed circuit board (FPC)
30 ... Fixing member (clamp)
31 ... Connection part

Claims (5)

A plurality of battery cells;
An electrode provided in the battery cell;
An electrode terminal provided protruding from the surface of the electrode;
A control unit for detecting and controlling the voltage of the battery cell;
A flexible printed circuit board connecting the control unit and the battery cell;
The flexible printed circuit board is directly connected to the electrode terminals,
A battery module, wherein a connecting portion between the flexible printed circuit board and the electrode terminal is fixed by a fixing member. In the flexible printed circuit board, an electrode insertion hole smaller than the outer periphery of the electrode terminal,
The battery module according to claim 1, wherein a slit formed in a direction of an outer peripheral edge of the flexible printed circuit board is provided from a hole wall of the electrode insertion hole. The battery module according to claim 2, wherein the flexible printed circuit board is provided with a plurality of slits, and a crease that connects adjacent slits is formed. The joint terminal which electrically connects the said electrode terminal provided in the said battery cell, and the electrode terminal provided in another battery cell adjacent to the said battery cell is characterized by the above-mentioned. Item 4. The battery module according to any one of Items 3 to 3. A bus bar that electrically connects the electrode terminal provided in the battery cell and the electrode terminal provided in another battery cell adjacent to the battery cell;
2. The electrode terminal according to claim 1, wherein a screw thread for screwing a screw member for fixing the bus bar and a stepped surface on which the bus bar or the flexible printed board is placed are formed. Item 4. The battery module according to any one of Items 3 to 3.

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