JP7188332B2 - battery module - Google Patents

Description

The disclosure provided herein relates to battery modules.

As disclosed in Patent Document 1, a bipolar battery is known that includes a laminate including a plurality of unit cells stacked in the stacking direction, and a restraint that restrains the stack in the stacking direction.

JP 2018-28977 A

As described above, the laminate of the bipolar battery described in Patent Document 1 includes a plurality of unit cells. However, a specific configuration for detecting the voltages of these unit cells has not been disclosed. Also, the plurality of unit cells (battery cells) expands. Therefore, a voltage detection mechanism that suppresses electrical connection failure due to the expansion is desired.

Therefore, an object of the disclosure described in this specification is to provide a battery module having a voltage detection mechanism for a plurality of battery cells, which suppresses the occurrence of poor electrical connection due to swelling of the plurality of battery cells. .

One disclosed is a plurality of battery cells (13) having two electrodes (15, 16) spaced apart in the stacking direction, and a plurality of battery cells (13) connected to each of the plurality of electrodes in a manner facing each other in the stacking direction. a laminate (10) comprising a conductive plate (12);
a holding part (30) for holding the arrangement of the plurality of battery cells and the plurality of conductive plates in the stacking direction;
Formation of a plurality of through holes (51) arranged opposite to the laminate in a vertical direction orthogonal to the lamination direction and connected to a plurality of conductive protrusions (20) extending in a manner spaced apart from each of the plurality of conductive plates. and a wiring board (50),
The plurality of conductive protrusions are arranged in the stacking direction so as to face each other while being spaced apart in the stacking direction.

According to this, the voltages of the plurality of battery cells (13) are input to the wiring board (50) through the conductive protrusions (20). Thereby, voltages of a plurality of battery cells (13) can be detected.

The stacking direction of the plurality of battery cells (13) and the plurality of conductive plates (12) is held by a holding portion (30). Therefore, variation in the distance (interval) between the plurality of conductive projections (20) in the stacking direction due to expansion of the plurality of battery cells (13) in the stacking direction is suppressed. This suppresses variation in the relative positions of the plurality of conductive projections (20) and the plurality of through holes (51) in the stacking direction. The application of stress to the connecting portion between the conductive protrusion (20) and the through hole (51) is suppressed. The occurrence of electrical connection failure between the wiring board (50) and the conductive protrusion (20) is suppressed.

It should be noted that the reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments described later, and do not limit the technical scope in any way.

FIG. 4 is a top view of the battery module; FIG. 3 is a side view of the battery module; It is a front view of a battery module. 4 is a chart for explaining a laminate and restraints; 4 is a chart for explaining a laminate and restraints; 4 is a chart for explaining a wiring board; FIG. 4 is a chart for explaining a wiring board; FIG. 4 is a chart for explaining the cover; 4 is a chart for explaining the cover; FIG. 2 is a cross-sectional view along line XX of FIG. 1; FIG. 2 is a cross-sectional view along line XI-XI of FIG. 1; 3 is a cross-sectional view along line XII-XII in FIG. 2; FIG. FIG. 11 is a side view showing a modification of the battery module;

Embodiments will be described below with reference to the drawings.

(First embodiment)
A battery module according to the present embodiment will be described with reference to FIGS. 1 to 12. FIG. The battery module of this embodiment is applied to vehicles such as electric vehicles and plug-in hybrid vehicles.

The three directions that are orthogonal to each other are hereinafter referred to as the x-direction, the y-direction, and the z-direction. The x direction corresponds to the horizontal direction. The y direction corresponds to the vertical direction. The z direction corresponds to the stacking direction.

<In-vehicle power supply>
1 to 3 show the appearance of the battery module 100. FIG. A plurality of battery modules 100 are mounted on a vehicle. A plurality of battery modules 100 are connected in series by a wire harness or the like. This constitutes an in-vehicle power supply. The on-board power supply functions to power the electrical loads of the vehicle. Of course, one battery module 100 may constitute an in-vehicle power source.

Air is supplied to the onboard power supply from a fan mounted on the vehicle. This suppresses excessive temperature changes in the onboard power supply. It is also possible to employ a configuration in which the temperature of the vehicle-mounted power source is adjusted with a liquid coolant.

For example, the space under the front seats of the vehicle, the space under the rear seats, the space between the rear seats and the trunk room, and the like can be appropriately adopted as the location of the on-vehicle power supply.

<Overview of battery module>
The battery module 100 shown in FIGS. 1-3 has a stack 10, restraints 30, and a cover . The wiring substrate 50 shown in FIGS. 6 and 7 is included inside the cover 70 . The laminate 10 includes a plurality of unit cells 11 having power generation functions. These plurality of unit cells 11 are stacked in the z-direction by restraints 30 . The wiring board 50 is electrically connected to each of the plurality of unit cells 11 . The cover 70 is connected to the restraint 30 so as to cover the wiring board 50 .

The laminate 10 is configured by stacking a plurality of unit cells 11 in the z direction. Although it has such a configuration, as shown in FIGS. 2 and 3, the laminated body 10 has a length in the z direction shorter than each length in the x direction and the y direction.

As shown in FIG. 10, which is a cross-sectional view along line XX of FIG. and a sealing member 14 surrounding the power generating element 13 between the two conductive plates 12 . Two unit cells 11 adjacent to each other in the z-direction share one conductive plate 12 positioned between them. Due to this configuration, the total number of conductive plates 12 is one more than the total number of power generation elements 13 .

As shown in FIGS. 4 and 5, which are extracts of only the restraining structure of battery module 100 shown in FIGS. . The first pressing plate 31 and the second pressing plate 32 are arranged apart in the z direction. A laminate 10 is provided between the first pressing plate 31 and the second pressing plate 32 . The first pressing plate 31 and the second pressing plate 32 are connected by a connecting portion 33 so as to approach each other in the z direction. As a result, the laminate 10 provided between the first pressing plate 31 and the second pressing plate 32 is compressed in the z direction. This compression maintains the alignment of the plurality of unit cells 11 in the z direction and electrically connects the plurality of unit cells 11 .

The restraint 30 corresponds to the holding part. Section (a) of FIG. 4 shows a top view of the laminate and the restraint. Column (b) of FIG. 4 and column (a) of FIG. 5 show side views of the laminate and the restraint. Column (b) of FIG. 5 shows a front view of the laminate and the restraint.

Conductive protrusions 20 that locally extend in the y direction are formed on each of the plurality of conductive plates 12 . The plurality of conductive projections 20 are at the same potential as each of the plurality of power generation elements 13 . These plurality of conductive protrusions 20 are connected to a wiring board 50 shown in FIGS.

The wiring board 50 shown in FIGS. 6 and 7 arranged in the cover 70 shown in FIGS. 1 and 2 is a printed board having a conductive wiring pattern formed on an insulating substrate. The wiring board 50 is provided so as to face the laminate 10 shown in FIGS. 4 and 5 in the y direction. A plurality of conductive protrusions 20 shown in FIGS. 4 and 5 are inserted into the plurality of through holes 51 formed in the wiring substrate 50, respectively. These are connected by solder. Thereby, the voltages of the plurality of unit cells 11 shown in FIGS. 4 and 5 are input to the wiring board 50 .

A monitoring unit is formed on the wiring board 50 . Voltages of the plurality of unit cells 11 shown in FIGS. 4 and 5 are input to the wiring board 50 . A connector 52 is provided on the wiring board 50 . External devices such as a battery ECU and an auxiliary battery mounted on the vehicle are connected to the connector 52 . The monitoring unit formed on the wiring board 50 is driven by power supplied from the auxiliary battery. The monitoring unit converts the input voltages of the plurality of unit cells 11 from analog signals to digital signals. Then, the monitoring unit outputs the converted digital signal to the battery ECU mounted on the vehicle by communication.

The cover 70 has a box shape that opens in the y direction. Cover 70 is connected to restraint 30 shown in FIGS. 4 and 5 in such a manner that at least part of wiring board 50 is housed in the hollow of cover 70 . A through hole 71c is formed in the cover 70 for communicating the hollow of the cover 70 with the external space. The distal end side of the connector 52 is arranged outside the hollow of the cover 70 (external space) through the through hole 71c. The constituent elements of the battery module 100 shown in FIGS. 1 to 3 will be individually described below.

<Unit cell>
As shown in FIG. 10 , unit cell 11 has conductive plate 12 , power generating element 13 , and sealing member 14 . A power generating element 13 and a sealing member 14 are provided between two conductive plates 12 . A positive electrode 15 of the power generation element 13 is connected to one of the two conductive plates 12 . A negative electrode 16 of the power generation element 13 is connected to the other of the two conductive plates 12 . The conductive plate 12, positive electrode 15, and negative electrode 16 constitute a so-called bipolar electrode.

The conductive plate 12 is manufactured by pressing a conductive metal plate such as a nickel plate or a nickel-plated copper plate. As shown in FIG. 4, the conductive plate 12 has a flat shape with a thin thickness in the z direction. The conductive plate 12 has a rectangular flat plate shape with the y direction as the longitudinal direction and the x direction as the lateral direction.

The conductive plate 12 has an upper surface 12a and a lower surface 12b spaced apart in the z-direction, and side surfaces connecting these surfaces. The upper surface 12a and the lower surface 12b are larger in area than the side surfaces.

As shown in FIG. 12, the side surface of the conductive plate 12 has a front surface 12c and a rear surface 12d aligned in the y direction, and a left surface 12e and a right surface 12f aligned in the x direction. Each of the front surface 12c and the rear surface 12d extends in the x direction. Each of the left surface 12e and the right surface 12f extends in the y direction.

As shown in FIG. 10, the power generating element 13 has a positive electrode 15, a negative electrode 16, and a separator 17. The cathode 15 is a metal containing a cathode active material such as nickel hydride. The negative electrode 16 is a metal containing a negative electrode active material such as a hydrogen storage alloy. The separator 17 is a non-woven fabric containing an electrolytic solution such as an aqueous potassium hydroxide solution. The power generation element 13 corresponds to a battery cell.

Each of the positive electrode 15 and the negative electrode 16 has a flat plate shape with a thin thickness in the z direction. The separator 17 has a flat plate shape with a thin thickness in the z direction. The upper and lower surfaces of the positive electrode 15 and the negative electrode 16, which are aligned in the z-direction, have larger areas than the side surfaces connecting them. Each of the positive electrode 15 and the negative electrode 16 has a smaller physical size than the separator 17 in a plane perpendicular to the z direction.

The separator 17 has an upper major surface 17a and a lower major surface 17b spaced apart in the z-direction, and a side surface connecting them. The upper main surface 17a and the lower main surface 17b are larger in area than the side surfaces.

A positive electrode 15 is provided on the central side of the upper main surface 17 a of the separator 17 . A negative electrode 16 is provided on the central side of the lower main surface 17b. The positive electrode 15 and the negative electrode 16 are not provided on the end sides of the upper main surface 17a and the lower main surface 17b.

In this manner, the positive electrode 15 and the negative electrode 16 are laminated in the z direction with the separator 17 interposed therebetween. The separator 17 has a property of allowing electrons to pass but not to molecules. Electrons (current) flow between the positive electrode 15 and the negative electrode 16 via the separator 17 containing the electrolytic solution.

The power generation element 13 is charged and discharged by an oxidation-reduction reaction. The power generation element 13 generates gas such as hydrogen by this oxidation-reduction reaction. Also, the electrolyte generates gas due to deterioration over time. When these gases are contained in the separator 17, the resistance between the positive electrode 15 and the negative electrode 16 increases. As a result, the output of the unit cell 11 is lowered.

In order to avoid this, it is necessary to apply pressure to the power generating element 13 to suppress generation of gas due to aged deterioration of the electrolyte. Also, it is necessary to prevent gas from accumulating in the separator 17 . Such pressure application to the power generation element 13 is achieved by the restraint 30 .

The sealing member 14 functions to suppress leakage of the electrolyte. The seal member 14 has an annular shape in the circumferential direction around the z-direction. The seal member 14 has an annular upper surface 14a and an annular lower surface 14b spaced apart in the z-direction. The annular upper surface 14a and the annular lower surface 14b form an annular shape in the circumferential direction around the z-direction.

As described above, the seal member 14 is provided between the two conductive plates 12 in the z-direction. An annular upper surface 14a of the sealing member 14 is in contact with the lower surface 12b of one of the two conductive plates 12 over the entire circumference. An annular lower surface 14b of the sealing member 14 is in contact with the other upper surface 12a of the two conductive plates 12 over the entire circumference. A closed space is formed by the sealing member 14 and the two conductive plates 12 . A power generation element 13 is provided in this closed space. Thus, the seal member 14 and the two conductive plates 12 serve as a case for housing the power generation element 13 .

In this closed space, the positive electrode 15 is provided on the central side of the lower surface 12b of one of the two conductive plates 12 . A negative electrode 16 is provided on the center side of the upper surface 12 a of the other of the two conductive plates 12 .

The two conductive plates 12 are displaced so as to approach each other in the z direction due to the compression in the z direction by the restraint 30 described above. As a result, the seal member 14 provided between the two conductive plates 12 is compressed in the z direction. The gap between the two conductive plates 12 and the sealing member 14 is closed.

Also, the lower surface 12b of one of the two conductive plates 12 and the positive electrode 15 are in contact with each other in a compressed manner. The upper surface 12a of the other of the two conductive plates 12 and the negative electrode 16 are in contact with each other in a compressed manner. Thereby, the two conductive plates 12 and the power generation element 13 are electrically connected. Along with this, a plurality of unit cells 11 are arranged in series in the z-direction and electrically connected in series.

As described above, the conductive plate 12, the positive electrode 15, the negative electrode 16, and the separator 17 provided in the unit cell 11 have upper and lower surfaces aligned in the z-direction and have larger areas than side surfaces. And these are connected at the center side of the upper surface and the lower surface. Therefore, the center side of the unit cell 11 expands more easily in the z direction than the end sides.

<Conductive protrusion>
As shown in FIGS. 4 and 5, a conductive protrusion 20 is formed on the front surface 12c of the conductive plate 12 and locally extends in the y-direction while being spaced apart from the conductive plate 12. As shown in FIG. This conductive protrusion 20 serves as a terminal for taking out the voltage of the power generating element 13 shown in FIG.

The conductive plates 12 provided in each of the plurality of unit cells 11 have the same shape. The plurality of unit cells 11 are stacked in the z direction in such a manner that the positions of the conductive protrusions 20 provided in each of the plurality of unit cells 11 are the same in the x direction.

With the plurality of unit cells 11 stacked in the z-direction in this way, the plurality of conductive projections 20 are arranged in the z-direction so as to face each other while being spaced apart in the z-direction. All the other conductive projections 20 are positioned at any one of the plurality of conductive projections 20 projected in the z-direction. The positions of the plurality of conductive protrusions 20 in the x direction are the same. The distances (intervals) between the plurality of conductive projections 20 in the z direction are the same.

<Restraint>
As shown in FIGS. 4 and 5 , the restraint 30 has a first pressing plate 31 , a second pressing plate 32 and a connecting portion 33 .

The first pressing plate 31 is made of a highly rigid metal material. The first pressing plate 31 has a rectangular parallelepiped shape. The first pressing plate 31 has a first outer surface 31a and a first inner surface 31b spaced apart in the z-direction, and a first connecting surface connecting them.

The first connecting surface has a first front surface 31c and a first rear surface 31d aligned in the y direction, and a first left surface 31e and a first right surface 31f aligned in the x direction. Each of the first front surface 31c and the first rear surface 31d extends in the x direction. Each of the first left surface 31e and the first right surface 31f extends in the y direction.

As indicated by the dashed line in column (a) of FIG. 4, a first bolt hole 31g is formed in the first pressing plate 31 where the first bolt 35 is arranged. As shown in FIG. 11, which is a cross-sectional view taken along line XI-XI in FIG. 1, the first bolt hole 31g opens to the first outer surface 31a and the first inner surface 31b. A plurality of first bolt holes 31 g are formed on the edge side of the first pressing plate 31 . The plurality of first bolt holes 31g are arranged in a ring so as to surround the central side of the first pressing plate 31 .

In this embodiment, a total of ten first bolt holes 31g are formed in the first pressing plate 31. As shown in FIG. Four of the ten first bolt holes 31g are formed at the four corners of the first pressing plate 31 .

One first bolt hole 31g is formed between the two first bolt holes 31g formed at the corners on each of the first front surface 31c side and the first rear surface 31d side. Three first bolt holes 31g are arranged in the x direction on each of the first front surface 31c side and the first rear surface 31d side. The distances between the three first bolt holes 31g arranged in the x direction are equal.

Two first bolt holes 31g are formed between the two first bolt holes 31g formed at the corners on the first left surface 31e side and the first right surface 31f side, respectively. Four first bolt holes 31g are arranged in the y direction on each of the first left surface 31e side and the first right surface 31f side. The intervals between the four first bolt holes 31g arranged in the y direction are equal.

The second pressing plate 32 has the same shape as the first pressing plate 31 . The second pressing plate 32 has a rectangular parallelepiped shape. The second pressing plate 32 has a second outer surface 32a and a second inner surface 32b spaced apart in the z-direction, and a second connecting surface connecting them.

The second connecting surface has a second front surface 32c and a second rear surface 32d aligned in the y direction, and a second left surface 32e and a second right surface 32f aligned in the x direction. Each of the second front surface 32c and the second rear surface 32d extends in the x direction. Each of the second left surface 32e and the second right surface 32f extends in the y direction. In a plane facing the z-direction, the second front surface 32c, the second rear surface 32d, the second left surface 32e, and the second right surface 32f are the first front surface 31c, the first rear surface 31d, and the first rear surface 31d of the first pressing plate 31. It has the same positional relationship as the first left surface 31e and the first right surface 31f.

Although not shown in FIGS. 4 and 5, the second pressing plate 32 is formed with a second bolt hole 32g equivalent to the first bolt hole 31g. As shown in FIG. 11, which is a cross-sectional view taken along line XI-XI in FIG. 1, the second bolt hole 32g opens to the second outer surface 32a and the second inner surface 32b.

In this embodiment, a total of ten second bolt holes 32g are formed in the second pressing plate 32. As shown in FIG. The arrangement locations of the ten second bolt holes 32g on the plane facing the z direction are the arrangement locations of the first bolt holes 31g on the plane facing the z direction indicated by broken lines in column (a) of FIG. is equivalent to A plurality of second bolt holes 32 g are formed on the edge side of the second pressing plate 32 . The plurality of second bolt holes 32g are arranged in an annular shape so as to surround the central side of the second pressing plate 32. As shown in FIG.

Four of the ten second bolt holes 32 g are formed at the four corners of the second pressing plate 32 . One second bolt hole 32g is formed between the two second bolt holes 32g formed at the corners on each of the second front surface 32c side and the second rear surface 32d side. Three second bolt holes 32g are arranged in the x direction on each of the second front surface 32c side and the second rear surface 32d side. The distances between the three second bolt holes 32g arranged in the x direction are equal.

Two second bolt holes 32g are formed between the two second bolt holes 32g formed at the corners on the second left face 32e side and the second right face 32f side, respectively. Four second bolt holes 32g are arranged in the y direction on each of the second left surface 32e side and the second right surface 32f side. The intervals between the four second bolt holes 32g arranged in the y direction are equal.

As shown in FIG. 11, the first pressure plate 31 and the second pressure plate 32 are arranged to face each other in the z direction such that the first inner surface 31b and the second inner surface 32b face each other. A total of ten first bolt holes 31g formed in the first pressing plate 31 and a total of ten second bolt holes 32g formed in the second pressing plate 32 are arranged to face each other in the z direction. Connecting portions 33 are provided between the ten first bolt holes 31g and the ten second bolt holes 32g.

As shown in FIG. 11, the connecting portion 33 has a connecting shaft 34, a first bolt 35 and a second bolt 36. As shown in FIG. The connecting shaft 34 has a columnar shape extending in the z direction. The connecting shaft 34 has a first end surface 34a and a second end surface 34b facing in the z direction. The connecting shaft 34 is formed with a first connecting hole 34c opening at the first end surface 34a and a second connecting hole 34d opening at the second end surface 34b.

As shown in FIG. 11, the first end surface 34a of the connecting shaft 34 and the first inner surface 31b of the first pressing plate 31 are arranged to face each other in the z direction. The hollow of the first connecting hole 34c and the hollow of the first bolt hole 31g are communicated in the z direction.

As shown in FIG. 11, the shaft portion of the first bolt 35 is inserted from the opening of the first bolt hole 31g on the side of the first outer surface 31a toward the hollow of the first bolt hole 31g and the hollow of the first connecting hole 34c. . A screw groove is formed in the first connecting hole 34c. The tip side of the shaft portion of the first bolt 35 is fastened to this thread groove. The head of the first bolt 35 contacts the first outer surface 31a. As a result, the first pressing plate 31 is sandwiched between the connecting shaft 34 and the head of the first bolt 35 in the z direction. The first pressing plate 31 is screwed to the connecting shaft 34 .

Similarly, the second end surface 34b of the connecting shaft 34 and the second inner surface 32b of the second pressing plate 32 are arranged to face each other in the z direction. The hollow of the second connecting hole 34d and the hollow of the second bolt hole 32g are communicated in the z direction.

The shaft portion of the second bolt 36 is inserted from the opening of the second bolt hole 32g on the side of the second outer surface 32a toward the hollow of the second bolt hole 32g and the hollow of the second connecting hole 34d. A screw groove is formed in the second connecting hole 34d. The tip side of the shaft portion of the second bolt 36 is fastened to this thread groove. The head of the second bolt 36 contacts the second outer surface 32a. As a result, the second pressing plate 32 is sandwiched between the connecting shaft 34 and the head of the second bolt 36 in the z direction. The second pressing plate 32 is screwed to the connecting shaft 34 .

The restraint 30 is assembled by connecting the first pressing plate 31 and the second pressing plate 32 via the connecting portion 33 described above. Before assembling the restraint 30 in this way, the laminate 10 having the plurality of unit cells 11 shown in FIG. Then, the first pressing plate 31 and the second pressing plate 32 are screwed to the connecting portion 33 as described above.

In this screw tightening process, the first pressing plate 31 and the second pressing plate 32 approach each other in the z direction. As a result, the laminate 10 provided between the first pressing plate 31 and the second pressing plate 32 is compressed in the z direction. That is, as shown in FIG. 10, multiple unit cells 11 are compressed in the z direction. The conductive plate 12 and the power generation element 13 are electrically connected in each of the plurality of unit cells 11 . Along with this, a plurality of unit cells 11 are electrically connected in series.

A plurality of unit cells 11 connected in series are arranged in the z-direction in order of potential. Therefore, among the plurality of unit cells 11 connected in series, the unit cells 11 positioned at the lowest potential and the highest potential are positioned at both ends. The unit cell 11 positioned at the lowest potential is positioned on the second pressing plate 32 side. The unit cell 11 positioned at the highest potential is positioned on the first pressing plate 31 side.

Of the two conductive plates 12 provided in the unit cell 11 positioned at the lowest potential, the conductive plate 12 connected to the negative electrode 16 is positioned on the second pressing plate 32 side in the z direction. Of the two conductive plates 12 provided in the unit cell 11 positioned at the highest potential, the conductive plate 12 connected to the positive electrode 15 is positioned on the first pressing plate 31 side in the z direction.

When the conductive plate 12 and the pressing plate are in direct contact, they are electrically connected. The negative electrode 16 of the unit cell 11 positioned at the lowest potential and the positive electrode 15 of the unit cell 11 positioned at the highest potential are short-circuited via the restraint 30 .

In order to prevent this, the following configuration or the like is appropriately employed in the battery module 100 shown in FIGS. 1 to 3. FIG. For example, an insulator is interposed between the conductive plate 12 and the pressing plate. At least one of the pressing plate and the connecting shaft 34 is made of insulating resin. An insulating member having a screw groove is provided in each of the first connecting hole 34c and the second connecting hole 34d.

In this embodiment, although not shown, there is a gap between the conductive plate 12 and the second pressing plate 32 of the unit cell 11 shown in FIG. 31 is provided with a heat insulating member having insulating properties and heat insulating properties.

As shown in FIGS. 4 and 5, the first front surface 31c of the first pressing plate 31 is formed with two first protrusions 31h that protrude in the y direction. These two first protrusions 31h are spaced apart in the x direction. As shown in FIG. 11, each of these two first protrusions 31h is formed with a first connecting bolt hole 31i that opens to the tip surface of the first protrusion 31h.

Similarly, as shown in FIGS. 4 and 5, the second front surface 32c of the second pressing plate 32 is formed with two second protrusions 32h that protrude in the y direction. These two second protrusions 32h are spaced apart in the x direction. As shown in FIG. 11, each of these two second protrusions 32h is formed with a second connecting bolt hole 32i that opens to the tip surface of the second protrusion 32h.

As shown in FIGS. 4 and 5, one of the two first projections 31h and one of the two second projections 32h are spaced apart from each other in the z direction. The remaining one first protrusion 31h and the remaining one second protrusion 32h are lined up while being spaced apart in the z direction. The y-direction positions of the tip surfaces of the two first protrusions 31h and the tip surfaces of the two second protrusions 32h are the same. Wiring substrates 50 shown in FIGS. 6 and 7 are provided on these four tip surfaces.

<Wiring board>
As shown in FIGS. 6 and 7, the wiring substrate 50 is an insulating substrate on which wiring patterns are formed. The wiring board 50 has a flat shape with a thin thickness in the y direction. The wiring board 50 has a rectangular flat plate shape with the longitudinal direction in the x direction and the lateral direction in the z direction.

Column (a) of FIG. 6 shows a front view of the wiring board. Column (b) of FIG. 6 shows a side view of the wiring board. Column (c) of FIG. 6 shows a rear view of the wiring board. In addition, column (a) of FIG. 7 shows a front view of the wiring board in the same manner as column (a) of FIG. 6 . Column (b) of FIG. 7 shows a side view of the wiring board.

The wiring board 50 has a facing surface 50a and a mounting surface 50b spaced apart in the y direction, and a third connecting surface connecting these surfaces. The third connecting surface has a third upper surface 50c and a third lower surface 50d aligned in the z direction, and a third left surface 50e and a third right surface 50f aligned in the x direction. Each of the third upper surface 50c and the third lower surface 50d extends in the x direction. Each of the third left surface 50e and the third right surface 50f extends in the z direction.

The wiring board 50 is formed with a plurality of through holes 51 that open to the facing surface 50a and the mounting surface 50b. The plurality of through holes 51 are located on the third left surface 50e side in the x direction. The plurality of through-holes 51 are spaced apart in the z-direction between the third upper surface 50c and the third lower surface 50d. The plurality of through holes 51 are equally spaced apart in the z direction. The adjacent intervals of the plurality of through holes 51 in the z direction are the same as the intervals in the z direction of the plurality of conductive protrusions 20 shown in FIGS. 10 and 12 .

As shown in FIGS. 10 and 12, the wiring board 50 is arranged to face the laminate 10 in such a manner that the facing surface 50a faces the laminate 10 in the y direction. Conductive protrusion 20 is inserted from the opening of through hole 51 on the facing surface 50a side toward the hollow thereof. Conductive projection 20 and through hole 51 are electrically connected via solder.

As shown in FIGS. 6 and 7, a connector 52 is mounted on the mounting surface 50b of the wiring board 50. As shown in FIG. The connector 52 has a tubular portion made of resin and opening in the y direction, and connection terminals provided in the hollow of the tubular portion.

The connector 52 is positioned on the third right surface 50f side in the x direction. The connector 52 and the plurality of through holes 51 are separated in the x direction. The connection terminals of the connector 52 and the through holes 51 are electrically connected via a wiring pattern (not shown). A filter or the like for removing noise may be provided in this wiring pattern.

The wiring board 50 is formed with a plurality of connecting holes 50g that open to the facing surface 50a and the mounting surface 50b. In this embodiment, a total of four connecting holes 50g are formed in the wiring board 50. As shown in FIG. These four connecting holes 50g are formed at the four corners of the wiring board 50. As shown in FIG.

As shown in FIGS. 10 and 11, the wiring board 50 is arranged to face the laminate 10 in the y direction and also to face the restraint 30 in the y direction. One of the two ends of the wiring board 50 aligned in the z direction is arranged to face the first pressing plate 31 in the y direction. The other of the two ends is arranged to face the second pressing plate 32 in the y direction.

A formation region of the connecting hole 50g in the facing surface 50a of the wiring board 50 is arranged to face the tip surfaces of the first protrusion 31h and the second protrusion 32h in the y direction. The hollow of the connecting hole 50g arranged to face the first protrusion 31h and the hollow of the first connecting bolt hole 31i are communicated in the y direction. The hollow of the connecting hole 50g arranged to face the second protrusion 32h communicates with the hollow of the second connecting bolt hole 32i in the y direction. The shaft portion of the third bolt 73 shown in FIG. 11 is inserted into these.

<Cover>
The cover 70 has a bottom wall 71 and a peripheral wall 72, as shown in FIGS. Section (a) of FIG. 8 shows a front view of the cover. Column (b) of FIG. 8 shows a side view of the cover. Column (c) of FIG. 8 shows a rear view of the cover. Also, column (a) of FIG. 9 shows a front view of the cover in the same manner as column (a) of FIG. 8 . Column (b) of FIG. 9 shows a side view of the cover.

The bottom wall 71 has a flat shape with a thin thickness in the y direction. The bottom wall 71 has a rectangular flat plate shape with the x direction as the longitudinal direction and the z direction as the lateral direction. The bottom wall 71 has an inner bottom surface 71a and an outer bottom surface 71b that are aligned in the y-direction, and a connecting surface that connects them.

The bottom wall 71 is formed with a through hole 71c opening to the inner bottom surface 71a and the outer bottom surface 71b. The distal end side of the connector 52 shown in FIGS. 6 and 7 is arranged outside the hollow of the cover 70 through the through hole 71c.

As shown in FIGS. 8 and 9, the peripheral wall 72 rises from the inner bottom surface 71a of the bottom wall 71 in the y direction. The peripheral wall 72 extends annularly along the direction in which the edge of the inner bottom surface 71a extends. An annular inner peripheral surface 72 a of the peripheral wall 72 and an inner bottom surface 71 a of the bottom wall 71 define the hollow of the cover 70 .

As described above, the bottom wall 71 has a rectangular flat plate shape. For this reason, the cover 70 is originally formed with corners at the four corners of the bottom wall 71 . However, this corner is not formed in this embodiment. The four corners of the bottom wall 71 are locally notched, and the peripheral wall 72 extends in the y direction away from the bottom wall 71 at the four corners, and then faces the y direction away from the hollow of the cover 70. , and again in the y-direction. A total of four flat portions 72d are formed on the peripheral wall 72 so as to extend in the direction facing the y direction. A mounting hole 72c is formed through the flat portion 72d in the y direction. The mounting hole 72c opens to the inner peripheral surface 72a of the flat portion 72d and the outer peripheral surface 72b behind it.

As shown in FIGS. 10 and 11, the cover 70 is provided on the restraint 30 so that the inner bottom surface 71a of the bottom wall 71 faces the laminate 10, the restraint 30, and the wiring board 50 in the y direction. . The entire circumference of the distal end surface of the peripheral wall 72 of the cover 70 is arranged to face the restraint 30 in the y direction. Specifically, the distal end surface of the peripheral wall 72 is the first front surface 31c of the first pressure plate 31, the second front surface 32c of the second pressure plate 32, and the front surfaces of the pressure plates of the plurality of connecting shafts 34. It is arranged to face the side surfaces of the two connecting shafts 34 positioned on the end side in the y direction.

The hollows of the four mounting holes 72c described above communicate with the hollows of the four connecting holes 50g provided in the wiring board 50 in the y direction. As shown in FIG. 11, the shaft portion of the third bolt 73 is inserted from the opening of the mounting hole 72c on the side of the outer peripheral surface 72b toward the hollow of the mounting hole 72c and the hollow of the connecting hole 50g. Two of the shaft portions of these four third bolts 73 are inserted into the hollow of the first connecting bolt holes 31i. The shaft portions of the remaining two third bolts 73 are inserted into the hollows of the second connecting bolt holes 32i.

A screw groove is formed in each of the first connecting bolt hole 31i and the second connecting bolt hole 32i. The tip side of the shaft portion of the third bolt 73 is fastened to this thread groove. The head of the third bolt 73 contacts the outer peripheral surface 72b of the flat portion 72d of the cover 70. As shown in FIG. As a result, the cover 70 and the wiring board 50 are held between the restraint 30 and the head of the third bolt 73 in the y direction. The cover 70 and the wiring board 50 are screwed to the restraint 30 .

<Effect>
Each of the plurality of unit cells 11 has a power generation element 13 and a conductive plate 12 . The conductive protrusions 20 of the conductive plate 12 are connected to the through holes 51 of the wiring board 50 by soldering. Thereby, the voltages of the plurality of power generation elements 13 are input to the wiring board 50 . Voltages of the plurality of power generation elements 13 are detected.

Also, the conductive protrusion 20 of the conductive plate 12 that functions as a bipolar electrode is connected to the wiring board 50 . Therefore, an increase in the number of parts is suppressed compared to a configuration in which the conductive plate 12 and the wiring board 50 are indirectly electrically connected via a separate conductive member such as a wire.

As described above, the unit cell 11 tries to expand in the z-direction due to gas generation in the power generation element 13 . Due to this expansion, there is a possibility that the spacing in the z direction between the conductive protrusions 20 of the conductive plates 12 included in each of the plurality of unit cells 11 aligned in the z direction may vary.

On the other hand, a plurality of unit cells 11 are held in a row in the z direction by a restraint 30 . The conductive protrusions 20 included in the plurality of unit cells 11 extend in the y-direction and are spaced apart in the z-direction.

Therefore, variation in the z-direction spacing of the plurality of conductive projections 20 due to expansion of the power generation elements 13 included in each of the plurality of unit cells 11 in the z-direction is suppressed. This suppresses variation in the relative position in the z direction between each of the plurality of conductive protrusions 20 and each of the plurality of through holes 51 . The application of stress to the solder connecting the conductive protrusion 20 and the through hole 51 is suppressed. The occurrence of electrical connection failure between the conductive protrusion 20 and the wiring board 50 is suppressed.

Note that the center side of the unit cell 11 expands more easily than the end sides. Therefore, the degree of expansion of the plurality of unit cells 11 in the z direction is slightly different between the central side and the end side of the unit cell 11 . Although the plurality of unit cells 11 are held aligned in the z-direction by the restraint 30 as described above, if the first bolt 35 or the second bolt 36 is loosened or the like, the unit cells 11 expand and the plurality of conductive cells 11 are formed. There is a possibility that the distance between the protrusions 20 in the z direction may vary, albeit minutely. Then, there is a possibility that the variation in the separation interval will be different between the center side and the end side of the unit cell 11 .

On the other hand, in the present embodiment, as shown in column (b) of FIG. 5, the plurality of conductive projections 20 are positioned not on the central side of the unit cell 11 but on the end side in the x direction. The end sides of the unit cell 11 are more difficult to expand than the center side. For this reason, the expansion of the unit cell 11 makes it difficult for the spacing of the plurality of conductive protrusions 20 in the z direction to fluctuate. This effectively suppresses variation in reliability of electrical connection between each of the plurality of conductive protrusions 20 and the wiring board 50 .

The laminated body 10 has a length in the z direction shorter than each length in the x and y directions. That is, the laminate 10 has a length in the z direction shorter than a length in a direction orthogonal to the z direction. Therefore, the distance between the plurality of conductive protrusions 20 in the z direction is narrow. Thereby, the formation regions of the plurality of through holes 51 connected to the plurality of conductive protrusions 20 on the wiring board 50 can be consolidated. This facilitates connection between the plurality of conductive projections 20 and the plurality of through holes 51 .

In this embodiment, a heat insulating member is provided between the conductive plate 12 and the second pressure plate 32 of the unit cell 11 with the lowest potential and between the conductive plate 12 and the first pressure plate 31 of the unit cell 11 with the highest potential. is provided.

This suppresses heat conduction between the unit cells 11 positioned at both ends of the plurality of unit cells 11 and the restraint 30 . The occurrence of a temperature difference between the unit cells 11 positioned at both ends in the z-direction and the unit cells 11 positioned at the center side among the plurality of unit cells 11 is suppressed.

Therefore, the occurrence of temperature differences in the conductive plates 12 included in each of the plurality of unit cells 11 is suppressed. The occurrence of a difference in the degree of expansion and contraction due to thermal expansion of the plurality of conductive plates 12 is suppressed. The occurrence of a difference in the degree of expansion and contraction in the y direction of the conductive protrusions 20 formed on each of the plurality of conductive plates 12 is suppressed. Due to the difference in the degree of expansion and contraction of the plurality of conductive projections 20 in the y direction, the stress acting on the solder connecting the plurality of conductive projections 20 and the plurality of through holes 51 is suppressed. The occurrence of poor electrical connection between the conductive protrusion 20 and the wiring board 50 is more effectively suppressed.

A plurality of through holes 51 are formed in the wiring board 50 . Along with this, a connector 52 is mounted on the wiring board 50 . A plurality of through holes 51 and connectors 52 are spaced apart in the x direction.

As described above, the through holes 51 and the conductive protrusions 20 are connected via solder. Therefore, stress due to expansion of the unit cells 11 due to the gas and thermal expansion of the conductive plate 12 may act on the regions where the through holes 51 are formed in the wiring board 50 . As a result, there is a possibility that the formation region of the through hole 51 in the wiring substrate 50 is distorted.

External devices such as a battery ECU and an auxiliary battery are connected to the connector 52 . Therefore, there is a possibility that stress or the like due to connection with an external device may act on the mounting area of the connector 52 on the wiring board 50 . As a result, the mounting area of the connector 52 on the wiring board 50 may be distorted.

However, as described above, the through hole 51 and the connector 52 are separated in the x direction. Therefore, it is possible to prevent the strain generated in the region where the through hole 51 is formed in the wiring board 50 from affecting the connection between the connector 52 and the external device. It is possible to prevent the strain generated in the mounting area of the connector 52 on the wiring board 50 from affecting the connection between the through hole 51 and the conductive protrusion 20 .

Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present disclosure. is.

(First modification)
In this embodiment, an example in which the monitoring unit is formed on the wiring board 50 is shown. An example is shown in which an external device such as a battery ECU or an auxiliary battery is connected to the connector 52 provided on the wiring board 50 . However, for example, as shown in FIG. 13, a configuration in which a wire harness 90 is connected to the connector 52 and the monitoring unit is connected to the wire harness 90 can also be adopted. In this modified example, the connector 52 and the monitoring unit are connected via a wire harness 90 . This suppresses interference between the battery module 100 and the monitoring unit. In addition, it becomes difficult to limit the vehicle-mounted location of the monitoring unit with respect to the vehicle-mounted location of the battery module 100 .

(Second modification)
In this embodiment, an example is shown in which the connector 52 has a cylindrical portion made of resin that is open in the y direction, and connection terminals provided in the hollow of the cylindrical portion. However, it is also possible to employ a configuration in which the tubular portion opens in the x-direction or the z-direction. In this case, the insertion/removal directions of an external device such as a battery ECU, an auxiliary battery, and the wire harness 90 connected to the connector 52 are not the y direction but the x direction and the z direction.

(Third modification)
In this embodiment, the restraint 30 has a first pressure plate 31, a second pressure plate 32, and a connection portion 33, and the first pressure plate 31 and the second pressure plate 32 are connected in a manner that they approach each other in the z direction. An example in which the laminated body 10 is compressed in the z-direction by being connected by the portion 33 is shown. However, the restraint 30 is not limited to the above example. For example, instead of the connecting portion 33, a restraining band that restrains the first pressing plate 31 and the second pressing plate 32, or an elastic body that applies a biasing force to bring these two pressing plates closer to each other can be employed.

(Fourth modification)
In this embodiment, the configuration in which the conductive protrusion 20 extends from the conductive plate 12 is shown. However, a configuration in which the separate conductive protrusion 20 is fixed to the conductive plate 12 by, for example, welding can also be adopted.

(Fifth Modification)
In this embodiment, the wiring board 50 and the cover 70 are each fixed to the restraint 30 by the third bolts 73. As shown in FIG. However, it is also possible to employ a configuration in which the wiring board 50 and the cover 70 are fixed to the restraint 30 by different fixing members.

Moreover, an example in which the wiring board 50 and the cover 70 are each fixed to the pressing plate of the restraint 30 is shown. However, a configuration in which at least one of the wiring board 50 and the cover 70 is fixed to the connecting shaft can also be adopted.

DESCRIPTION OF SYMBOLS 10... Laminated body 12... Conductive plate 13... Power generation element 15... Positive electrode 16... Negative electrode 20... Conductive protrusion 30... Restraint 50... Wiring board 51... Through hole 52... Connector 100... battery module

Claims (5)

A plurality of battery cells (13) having two electrodes (15, 16) spaced apart in the stacking direction, and a plurality of conductive plates (12) connected to each of the plurality of electrodes so as to face each other in the stacking direction. ), a laminate (10) comprising
a holding part (30) for holding the arrangement of the plurality of battery cells and the plurality of conductive plates in the stacking direction;
A plurality of through holes (51) arranged opposite to the laminate in a vertical direction orthogonal to the lamination direction and connected to a plurality of conductive protrusions (20) extending in a manner spaced apart from each of the plurality of conductive plates. ) on which a wiring board (50) is formed,
A battery module in which the plurality of conductive protrusions are arranged in the stacking direction in a manner of facing each other while being spaced apart in the stacking direction. 2. The battery module according to claim 1, wherein each of said plurality of conductive protrusions extends in said longitudinal direction. 3. The position of each of the plurality of conductive projections in the horizontal direction orthogonal to the stacking direction and the vertical direction is on the side of the plurality of battery cells in the horizontal direction. battery module. The wiring board is provided with a connector (52) for electrically connecting to an external device,
A plurality of through-holes are formed on one side of two ends of the wiring board spaced apart in a horizontal direction orthogonal to the stacking direction and the vertical direction, and the other side of the two ends. 4. The battery module according to any one of claims 1 to 3, wherein the connector is provided in the . In addition to the battery cell and the conductive plate, the laminate includes a heat insulating member interposed between the conductive plate and the holding portion to suppress heat conduction between the conductive plate and the holding portion. The battery module according to any one of claims 1 to 4.

Images