Battery system

A battery system includes a plurality of electric rechargeable cells which are stacked in a row and conductive members which electrically connect the electric rechargeable cells together. The electric rechargeable cells each has a gas exhaust port, and a positive electrode terminal and a negative electrode terminal which are disposed in such a manner as to hold the gas exhaust port therebetween. The battery system includes a gas exhaust member connected to the gas exhaust ports, a partition holding member which establishes partitions between the gas exhaust member and the positive electrode terminals and the negative electrode terminals in such a manner as to cover them and on which the conductive members are provided, and a voltage control circuit which is attached to an outer surface side of the partition holding member in a position which confronts the gas exhaust member and controls voltages of the electric rechargeable cells.

TECHNICAL FIELD

The present disclosure relates to a battery system which is mounted on a fuel cell vehicle, an electric vehicle, a plug-in hybrid vehicle, and a hybrid vehicle.

RELATED ART

There is proposed, as an example of a related-art battery system, a battery system in which gas exhaust members on which fit-in type connecting portions and receiving type connecting portions are formed are provided on a plurality of lithium electric rechargeable cells. In the battery system, the plurality of electric rechargeable cells are connected to each other in such a manner that the fit-in type connecting portion of one gas exhaust member and the receiving type connecting portion of the adjacent gas exhaust member are connected to each other (for example, refer to Patent Document No. 1).[Patent Document No. 1] Japanese Patent Unexamined Application Publication No. 2002-216731

Normally, when electric rechargeable cells for a lithium ion secondary battery are mounted on a vehicle, a voltage control circuit (a cell controller) is necessary from the viewpoint of controlling the battery and preserving safety which monitors respective charged capacities of the electric rechargeable cells and controls charge and discharge of the electric rechargeable cells so as to make the charged capacities thereof uniform. In addition, there may emerge a case where gas exhaust ports are provided on the electric rechargeable cells for exhausting or expelling gases generated inside the electric rechargeable cells to the outside thereof.

In addition, as to shapes of electric rechargeable cells, there are electric rechargeable cells of cylindrical and angular shapes. As a battery system in which cylindrical electric rechargeable cells are used, a battery system500shown inFIG. 15is considered. In order that a positive electrode terminal, a negative electrode terminal and an exhaust port are made to coexist in one location, a positive electrode terminal503, a negative electrode terminal504and a gas exhaust port505are disposed altogether on an end face502of a cylindrical portion of an electric rechargeable cell501. Conductive members506are connected to the respective terminals503,504and a gas exhaust member507is connected to the gas exhaust port505.

In the battery system500configured as described above, however, since an area of the end face502of the electric rechargeable cell501is limited, it has been difficult that a conductive member506and a gas exhaust member507are attached to each of the plurality of electric rechargeable cells501.

In addition, as a battery system in which similar cylindrical electric rechargeable cells are used, a battery system600shown inFIG. 16is considered. A positive electrode terminal605and a negative electrode terminal606are disposed, respectively, on end faces603,604of a cylindrical portion of each of electric rechargeable cells602which are accommodated in a case601. Conductive members607are held by partition holding members608, and a gas exhaust member609is formed on the case601.

In the battery system600configured as described above, however, it has been difficult that the gas exhaust member609formed on the case601is made to connect to respective gas exhaust ports610of the electric rechargeable cells602and there has been a possibility that the number of partition holding members608is increased.

In addition, as a battery system in which angular electric rechargeable cells are used, a battery system700shown inFIG. 17is considered. A plurality of electric rechargeable cells701are disposed, a positive electrode terminal702and a negative electrode terminal703of adjacent electric rechargeable cells701are connected by a conductive member704, a gas exhaust member706is formed on a case705, and a voltage control circuit707is disposed on an outside of the case705.

In the battery system700configured as described above, however, since the case705and the voltage control circuit707are not configured integrally, the assembling properties are not good, and there has been a possibility that the battery system700is made large in size. In addition, since the voltage control circuit707is loaded above the terminals702,703, there has been a possibility that a problem such as short circuit occurs.

Furthermore, it has been difficult that a conductive member is fastened to each terminal of an electric rechargeable cell due to a recent tendency of an electric rechargeable cell becoming smaller in size and thinner in thickness.

It has been difficult from the viewpoint of layout to realize altogether the electric connection between the electric rechargeable cells and the voltage control circuit, connection between the gas exhaust ports and the gas exhaust member and fastening of the respective terminals of the electric rechargeable cells to the conductive members in the ways described above. In case these are really attempted to be realized altogether, it will be easy to seen that the resulting construction becomes complicated, and this has been the case with such an attempt. In addition, when the voltage control circuit is disposed outside the case, the assembling properties are not good, and there has been a possibility that the battery system is enlarged in size.

SUMMARY

Exemplary embodiments of the present invention provide a battery system which is simple in construction but is able to integrate electric rechargeable cells, respective terminals of the electric rechargeable cells, conductive members, a voltage control circuit and a gas exhaust member into a compact unit and which can increase the assembling properties of the battery system and realize the miniaturization of the battery system.

According to a first aspect of the invention, there is provided a battery system including a plurality of electric rechargeable cells (for example, electric rechargeable cells20of an embodiment) which are stacked in a row and conductive members (for example, conductive members11of the embodiment) which electrically connect the electric rechargeable cells together, the electric rechargeable cells each having a gas exhaust port (for example, a gas exhaust port24of the embodiment), as well as a positive electrode terminal (for example, a positive electrode terminal22of the embodiment) and a negative electrode terminal (for example, a negative electrode terminal23) which are disposed in such a manner as to hold the gas exhaust port therebetween, the battery system including a gas exhaust member (for example, a gas exhaust member80of the embodiment) connected to the gas exhaust ports, and a voltage control circuit (for example, a voltage control circuit70of the embodiment) provided in a position which confronts the gas exhaust member and lies between the positive electrode terminals and the negative electrode terminals and connected to the positive electrode terminals and the negative electrode terminals of the electric rechargeable cells for controlling voltages of the electric rechargeable cells. Herein, the term “electric rechargeable cell” used in the specification includes a battery, capacitor, etc.

According to a second aspect of the invention, there is provided a battery system including a plurality of electric rechargeable cells which are stacked in a row and conductive members which electrically connect the electric rechargeable cells together, the electric rechargeable cells each having a gas exhaust port, and a positive electrode terminal and a negative electrode terminal which are disposed in such a manner as to hold the gas exhaust port therebetween, the battery system including a gas exhaust member connected to the gas exhaust ports, a partition holding member40(for example, a partition holding member40of the embodiment) which establishes partitions between the gas exhaust member and the positive electrode terminals and the negative electrode terminals in such a manner as to cover the gas exhaust member and the positive electrode terminals and the negative electrode terminals and on which the conductive members are provided, and a voltage control circuit attached to an outer surface side of the partition holding member in a position which confronts the gas exhaust member for controlling voltages of the electric rechargeable cells.

According to a third aspect of the invention, there is provided a battery system as set forth in the first or second aspect of the invention, wherein the positive electrode terminals and the negative electrode terminals are each a plate-shaped member and are disposed in such a manner that plate surfaces thereof confront each other.

According to a fourth aspect of the invention, there is provided a battery system as set forth in any of the first to third aspects of the invention, wherein a first penetrating hole (for example, a first penetrating hole25of the embodiment) is provided in each of the positive electrode terminals and each of the negative electrode terminals and a second penetrating hole (for example, a second penetrating hole11aof the embodiment) is provided in each end portion of each of the conductive members, and wherein the positive electrode terminal, the negative electrode terminal and the conductive member are fixed together by fastening members (for example, fastening bolts13of the embodiment) which are inserted into the first penetrating holes and the second penetrating holes.

According to a fifth aspect of the invention, there is provided a battery system as set forth in the fourth aspect of the invention, wherein the first penetrating hole is formed into an elongated hole shape, and the adjacent conductive members are arranged in a zigzag fashion in a direction of the row of electric rechargeable cells so as to be connected to the positive electrode terminals and the negative electrode terminals.

According to a sixth aspect of the invention, there is provided a battery system as set forth in any of the first to fifth aspects of the invention, wherein a cell holder (for example, a cell holder30of the embodiment) is provided for holding the electric rechargeable cells, and wherein projecting portions (for example, projecting portions33of the embodiment) are provided on the cell holder for defining gaps between the electric rechargeable cells and the cell holder along which cooling air is caused to flow.

According to a seventh aspect of the invention, there is provided a battery system as set forth in any of the fourth to sixth aspects of the invention, wherein a threaded fastener member (for example, a nut member47of the embodiment) is provided which is conductive and into which the fastening member is screwed, and wherein the threaded fastener member and the voltage control circuit are electrically connected.

According to an eighth aspect of the invention, there is provided a battery system as set forth in any of the first to seventh aspects of the invention, wherein the gas exhaust ports are disposed in a row in a direction in which the electric rechargeable cells are stacked, and wherein the gas exhaust member has a plurality of exhaust pipes (for example, exhaust pipes82of the embodiment) and gases from the gas exhaust ports are divided so as to flow into the plurality of exhaust pipes.

According to a ninth aspect of the invention, there is provided a battery system as set forth in any of the first to seventh aspects of the invention, wherein the gas exhaust ports are disposed in a zigzag fashion in a direction in which the electric rechargeable cells are stacked, and wherein the gas exhaust member has a single exhaust pipe (for example, an exhaust pipe92of the embodiment) and gases from the gas exhaust ports are collected so as to flow into the single exhaust pipe.

According to a tenth aspect of the invention, there is provided a battery system as set forth in any of the first to seventh aspects of the invention, wherein the gas exhaust ports are disposed in a plurality of rows in a direction in which the electric rechargeable cells are stacked, and wherein the gas exhaust member has exhaust pipes (for example, exhaust pipes102of the embodiment) which are disposed correspondingly to the respective rows of exhaust ports and gases from the gas exhaust ports disposed in the plurality of rows are collected into the exhaust pipes.

According to an eleventh aspect of the invention, there is provided a battery system as set forth in any of the sixth to tenth aspects of the invention, including end face plates (for example, end face plates50of the embodiment) which are attached, respectively, to end faces of the cell holder and the partition holding member and a through-hole fastening member (for example, a through-hole fastening member60of the embodiment) which extends through the cell holder, the partition holding member, and the end face plates so as to fasten together the cell holder, the partition holding member and the end face plates.

According to the battery system set forth in the first aspect of the invention, the positive electrode terminals and the negative electrode terminals of the electric rechargeable cells and the voltage control circuit can be connected to each other over a short distance, thereby making it possible to make the battery system smaller in size.

According to the battery system set forth in the second aspect of the invention, the space between the positive electrode terminals and the negative electrode terminals is used effectively and the partition holding member has the layered construction. Therefore, the electric rechargeable cells, the respective terminals of the electric rechargeable cells, the conductive members, the voltage control circuit and the gas exhaust member can be integrated into a compact unit. In addition, since the voltage control circuit is incorporated into the battery system, the assembling properties of the system can be increased, thereby making it possible to realize the miniaturization of the battery system.

According to the battery system set forth in the third aspect of the invention, torque received by the electric rechargeable cells when the conductive member is connected to the electric rechargeable cells in such a manner as to expand between the adjacent electric rechargeable cells can be made to be borne by the threaded fastener members of the partition holding member when compared with a battery system in which terminals of electric rechargeable cells each have a round shaft shape. Therefore, the electric rechargeable cell can be made compact in terms of strength, thereby making it possible to realize the miniaturization of the battery system.

According to the battery system set forth in the fourth aspect of the invention, the conductive member can easily be fastened to the positive electrode terminal and the negative electrode terminal.

According to the battery system set forth in the fifth aspect of the invention, by arranging the adjacent conductive members in the zigzag fashion in the direction in which the electric rechargeable cells are stacked, a bolt larger in size is allowed to be used, thereby making it possible to increase the assembling properties.

According to the battery system set forth in the sixth aspect of the invention, the electric rechargeable cells can be cooled with good efficiency.

According the battery system set forth in the seventh aspect of the invention, the positive electrode terminals and the negative electrode terminals of the electric rechargeable cells can be connected to the voltage control circuit over a short distance via the threaded fastener members. This can serve to reduce the possibility that a problem such as short circuit is caused.

According to the battery system set forth in the eighth aspect of the invention, even in the event that gases are produced within the electric rechargeable cells, the pressure under which the gases are produced can be dispersed through the exhaust pipes into which the gases so produced are designed to be divided to flow so that the gases can be exhausted or expelled with good efficiency.

According to the battery system set forth in the ninth aspect of the invention, even in the event that gases are produced within the electric rechargeable cells, the pressure under which the gases are produced can be dispersed through the exhaust pipe into which the gases so produced are designed to be collected to flow so that the gases can be exhausted or expelled with good efficiency.

According to the battery system set forth in the tenth aspect of the invention, even in the event that gases are produced within the electric rechargeable cells, the pressure under which the gases are produced can be dispersed through the exhaust pipes which are disposed correspondingly to the rows of electric rechargeable cells so that the gases can be exhausted or expelled with good efficiency.

According to the battery system set forth in the eleventh aspect of the invention, the strong and rigid housing construction can be obtained as the whole of the battery system, thereby making it possible to increase the durability of the battery system.

Other features and advantages may be apparent from the following detailed description, the accompanying drawings and the claims.

DETAILED DESCRIPTION

Hereinafter, an embodiment of a battery system according to the invention will be described in detail based on the accompanying drawings. Note that the drawings are to be viewed in a direction in which reference numerals are oriented therein.

FIG. 1is a partially cutaway, exploded perspective view which illustrates one embodiment of a battery system according to the invention,FIG. 2is a partially cutaway front view of the battery system shown inFIG. 1,FIG. 3is a partially cutaway side view of the battery system shown inFIG. 1,FIG. 4is a partially cutaway side view which illustrates modified examples of terminals of the electric rechargeable cells,FIG. 5is a partially cutaway front view which illustrates a modified example of an assembling construction of a conductive member and a partition holding member,FIG. 6is a sectional view of a main part which illustrates an assembling construction of a through-hole fastening member,FIG. 7is a sectional view which illustrates a modified example to the assembling construction of the through-hole fastening member shown inFIG. 6,FIG. 8is a schematic perspective view of electric rechargeable cells and a gas exhaust member shown inFIG. 2,FIG. 9is an enlarged sectional view of a main part which illustrates a first modified example to a mounting construction of the gas exhaust member shown inFIG. 2,FIG. 10is an enlarged sectional view of a main part which illustrates a second modified example to the mounting construction of the gas exhaust member shown inFIG. 2,FIG. 11is a partially cutaway front view which illustrates a first modified example of a gas exhaust member,FIG. 12is a schematic perspective view of the electric rechargeable cells and the gas exhaust member shown inFIG. 11,FIG. 13is a partially cutaway front view which illustrates a second modified example of a gas exhaust member, andFIG. 14is a schematic perspective view of electric rechargeable cells and the exhaust member shown inFIG. 13.

As is shown inFIGS. 1 to 3, a battery system10of an embodiment of the invention includes mainly a plurality of electric rechargeable cells20, a plurality of plate-shaped conductive members11, a cell holder30, a partition holding member40, end face plates50, through-hole fastening members60, a lid portion12, a voltage control circuit70, and a gas exhaust member80. The plurality of plate-shaped conductive members11electrically connect the plurality of electric rechargeable cells20. The cell holder30holds the plurality of electric rechargeable cells20. The partition holding member40is provided in such a manner as to cover upper surfaces of the cell holder30. The end face plates50are attached, respectively, to front and rear end faces of the cell holder30and the partition holding member40. The through-hole fastening members60fasten the cell holder30, the partition holding member40and the end face plates50integrally. The lid portion12closes an upper opening of the partition holding member40. The voltage control circuit70is attached to the partition holding member40. The gas exhaust member80is connected to the plurality of electric rechargeable cells20.

The electric rechargeable cell20is an angular lithium ion secondary battery. The electric rechargeable cell20includes, as is shown inFIGS. 2 and 3, a battery main body21, a positive electrode terminal22, a negative electrode terminal23, and a gas exhaust port24. The positive electrode terminal22and the negative electrode terminal23are provided on an upper surface of the battery main body21at longitudinal end portions thereof in such a manner as to project therefrom. The gas exhaust port24is provided at a central portion of the upper surface of the battery main body21through which gas produced within the electric rechargeable cell20is exhausted or expelled. In addition, the plurality of electric rechargeable cells20are arranged alternately in opposite orientations in such a manner that the positive electrode terminals22and the negative electrode terminals23of the adjacent electric rechargeable cells20are staggered to be located alternately in opposite positions. The positive electrode terminal22of the electric rechargeable cell20and the negative electrode terminal23of the adjacent electric rechargeable cell20are electrically connected in series by the conductive member11.

In addition, the positive electrode terminal22and the negative electrode terminal23are each a plate-shaped member, and the positive electrode terminal22and the negative electrode terminal23are disposed in such a manner that plate surfaces thereof confront each other. Additionally, a round hole shaped first penetrating hole25is formed in each of the positive electrode terminal22and the negative electrode terminal23. A round hole shaped second penetrating hole11ais formed in each end portion of the conductive member11. Fastening bolts13are inserted in the first penetrating holes25of the respective terminals22,23and the second penetrating holes11aof the conductive member11. By the fastening bolts13being fastened by nut members47of the partition holding member40, which will be described later, the respective terminals22,23and the conductive member11are electrically connected.

In addition, as modified examples of a positive electrode terminal22and a negative electrode terminal23of the embodiment, as is shown inFIG. 4, elongated first penetrating holes25amay be formed in a positive electrode terminal22and a negative electrode terminal23. By this configuration, since the conductive members11can be arranged in a zigzag fashion in such a manner as to be offset vertically along a direction in which the electric rechargeable cells20are stacked, a thicker fastening bolt13is allowed to be used.

As is shown inFIGS. 2 and 3, the cell holder30is made by connecting a plurality of synthetic resin holder main bodies31in the direction in which the electric rechargeable cells20are stacked, so that the electric rechargeable cell20is held between the holder main bodies31. The holder main body31has a separation or dividing plate portion32which is disposed between the electric rechargeable cells20and projecting portions33which are formed, respectively, at upper and lower end portions of the dividing plate portion32for holding upper and lower end corner portions of the electric rechargeable cell20. In addition, by the electric rechargeable cells20being held by the projecting portions33, gaps34along which cooling air is caused to flow are formed between the electric rechargeable cells20and the cell holder30. In addition, the projecting portions33may be provided at mid portions of the dividing plate portions32. In addition, fastening member inserting portions35,35through which the through-hole fastening members60are inserted so as to extend are formed in a lower end portion of the cell holder30along the direction in which the electric rechargeable cells20are stacked.

The partition holding member40is made up of an insulating member which is made from synthetic resin. The partition holding member40has, as is shown inFIGS. 2 and 3, a pair of left and right side bodies41, and an alternately grooved and ridged plate portion42. The alternately grooved and ridged plate portion42is formed between the pair of left and right side bodies41. On an upper surface of the alternately grooved and ridged plate portion42, the voltage control circuit70is mounted. The partition holding member40establishes partitions between the gas exhaust member80and the positive electrode terminals22and the negative electrode terminals23in such a manner as to cover the gas exhaust member80and the positive electrode terminals22and the negative electrode terminals23. The conductive members11are provided on the partition holding member40.

In the alternately grooved and ridged plate portion42, a circuit accommodating portion43, and a gas exhaust member accommodating portion44. The circuit accommodating portion accommodates the voltage control circuit70between the upper surface thereof and the lid portion12. The gas exhaust member accommodating portion44accommodates the gas exhaust member80between a lower surface thereof and the cell holder30. Furthermore, fastening member inserting portions45,45through which the through-hole fastening members60are inserted so as to extend are formed between both side surfaces of the alternately grooved and ridged plate portion42and the pair of left and right side bodies41of the partition holding member40. By this configuration, since the partition holding member40is made to have a layered construction, the voltage control circuit70and the gas exhaust member80are incorporated in the partition holding member40in a compact fashion.

In addition, a plurality (a number equal to the number of electric rechargeable cells20) of terminal accommodating portions46for accommodating therein the respective terminals22,23of the electric rechargeable cells20are formed on a side surface portion of each of the side bodies41in the direction in which the electric rechargeable cells20are stacked.

In addition, nut members47into which the fastening bolt13is screwed to be fixed in place are embedded in the terminal accommodating portions46of the side bodies41in positions which confront to the first penetrating holes25of the terminals22,23of the electric rechargeable cells20.

Additionally, screw holes41bare formed in a plurality of locations on an upper step portion41aof each of the side bodies41in the direction in which the electric rechargeable cells20are stacked. By lid portion fixing screws12abeing screwed into the screw holes41bvia the lid portion12, the lid portion12is attached to the upper surface of the partition holding member40. In addition, an edge portion41cfor positioning the lid portion12in a width direction is formed along an outer side edge portion of each of the upper step portions41a.

In addition, as is shown inFIG. 3, rotation preventive projections48are formed within each terminal accommodating portion46of each side body41in positions which confront each other diagonally across the terminal22or23. The rotation preventive projections48are disposed in such a manner as to be brought into abutment with outer circumferential edge portions of each terminal22or23which are positioned to confront each other diagonally. The rotation preventive projections48function to prevent the application of load to the terminal22or23which causes the terminal22or23to rotate together with the fastening bolt13when the fastening bolt13is screwed into the nut member47.

Additionally, as a modified example of an assembling construction of the conductive members11and the partition holding member40, a construction as is shown inFIG. 5may be adopted when the respective terminals22,23are made of a material such as copper or aluminum which is relatively low in strength in which the conductive members11are disposed on a fastening bolt13side of the terminals22,23. By adopting this construction, since the fastening bolts13are allowed to contact the conductive members11which are thick and high in strength but are prevented from contacting the terminals22,23which are thin and low in strength, a risk that the terminals22,23may be damaged by the fastening bolts13can be avoided. In addition, as this occurs, a loose-fit hook49which supports the conductive member11in a floating state is provided within each terminal accommodating portion46of the partition holding member40so as to increase the assembling properties of the conductive member11to the partition holding member40. In addition, a hold spring mechanism, not shown, may be provided on the partition holding member40so as to prevent the loosening of the conductive member11to thereby increase the assembling properties.

As is shown inFIGS. 1 to 3, the end face plate50is made by laminating two plate members made from synthetic resin one on the other. The end face plate50has one gas exhaust member inserting hole51which allows the gas exhaust member to extend therethrough, and four fastening member inserting holes52which allows the through-hole fastening members60to extend therethrough. In addition, the end face plates50are attached to the cell holder30and the partition holding member40in such a manner as to hold front and rear end faces thereof therebetween by the through-hole fastening members60.

As is shown inFIGS. 1 to 3, the through-hole fastening members60have cylindrical portions61, stud bolts62, and fastening nuts63. The cylindrical portions61are inserted to extend through the fastening member inserting portions35,35of the cell holder30and the fastening member inserting holes52,52formed on a lower side of the end face plates50. The cylindrical portions61are inserted to extend through the fastening member inserting portions45,45of the partition holding member40and the fastening member inserting holes52,52formed on an upper side of the end face plates50. The stud bolts62are inserted to extend through the cylindrical portions61. The fastening nuts63are screwed, respectively, on to screw portions formed on both end portions of the stud bolts62. By this configuration, the cell holder30, the partition holding member40and the end face plates50,50are fastened integrally, resulting in a strong and rigid housing construction as a whole.

In addition, as is shown inFIG. 6, the cylindrical portion63is supported tightly by a plurality of guide portions45a. The plurality of guide portions45aare formed in a zigzag fashion in the direction in which the electric rechargeable cells20are stacked in an interior of the fastening member inserting portion45, and have an inside diameter which is slightly larger than an outside diameter of the cylindrical portion61.

In addition, as an modified example of an assembling construction of the cylindrical portions61, as is shown inFIG. 7, the cylindrical portion61is inserted in fastening member inserting portion45with a predetermined gap existing between the guide portions45band the cylindrical portion61and is supported loosely by elastic pieces45cprovided on the plurality of guide portions45b. The plurality of guide portions45bare formed in a zigzag fashion in the direction in which the electric rechargeable cells20are stacked in an interior of the fastening member inserting portion45and have a inside diameter larger than the outside diameter of the cylindrical portion61.

As is shown inFIG. 1, the voltage control circuit70includes a circuit board71, various types of electronic devices72such as pluralities of integrated circuits, resistances and capacitors, and connecting wires73. The electronic devices72are packaged on the circuit board71. The number of connecting wires73corresponds to the number of electric rechargeable cells20, and the connecting wires73are provided on side edge portions of the circuit board71. The connecting wire73is fastened to a lower step portion41dof the side body41and the nut member47by a connecting wire fixing screw74, so as to be electrically connected to the nut member47. By this configuration, the voltage control circuit70is electrically connected to the positive electrode terminals22and the negative electrode terminals23of the electric rechargeable cells20through the connecting wires73and the nut members47. Therefore, not only the charged capacities of the individual electric rechargeable cells20can be monitored but also charging and discharging thereof can be controlled so that the charged capacities of the individual electric rechargeable cells20become uniform. In addition, in this embodiment, the voltage control circuit70is provided between the positive electrode terminals22and the negative electrode terminals23of the electric rechargeable cells20.

As is shown inFIGS. 2 and 8, the gas exhaust member80has a plurality of dividing pipes81, two exhaust pipes82,82, and a collecting pipe83. The plurality of dividing pipes81are connected, respectively, to the gas exhaust ports24which are disposed in a row in the direction in which the electric rechargeable cells20are stacked. The plurality of dividing pipes81are each formed to have a V-shape as viewed from the top. The two exhaust pipes82,82are connected, respectively, to end portions of the plurality of dividing pipes81. The collecting pipe83is connected to one ends of the exhaust pipes82,82in such a manner that the exhaust pipes82,82are collected thereinto. A leading end portion of the collecting pipe83is led to the outside from the gas exhaust member inserting hole51formed in the end face plate50.

In addition, the gas exhaust member80is disposed in such a manner as to be brought into contact with a lower surface of the alternately grooved and ridged plate portion42of the partition holding member40at an upper surface thereof. Therefore, the gas exhaust member80is fixed to the gas exhaust ports24in such a way as to be pressed downwards by the partition holding member40. By this configuration, the gas exhaust member80can be prevented from being dislocated from the gas exhaust ports24due to a pressure under which exhaust gas is expelled from the gas exhaust ports24.

In addition, in case the gas exhaust member80is made from rubber, by the dividing pipes81being fitted in the corresponding gas exhaust ports24, airtightness can easily be ensured between the electric rechargeable cells20and the gas exhaust member80.

Additionally, as a first modified example of a mounting construction of the gas exhaust member80according to the embodiment, as is shown inFIG. 9, a configuration may be adopted in which the gas exhaust member80is made from synthetic resin, a recessed groove24ais formed on an outer circumferential surface of the gas exhaust port24of the electric rechargeable cell20, and a ring-shaped seal member24bis mounted in the recessed groove24a. Because of this configuration, by the dividing pipes81being fitted in the corresponding gas exhaust ports24, airtightness between the electric rechargeable cells20and the gas exhaust member80can be ensured further.

In addition, as a second modified example of a mounting construction of the gas exhaust member80according to the embodiment, as is shown inFIG. 10, a configuration may be adopted in which the gas exhaust member80is made from synthetic resin, a recessed groove81ais formed on an inner circumferential surface of the dividing pipe81of the gas exhaust member80, and a ring-shaped seal member81bis mounted in the recessed groove81a. Because of this configuration, by the dividing pipes81being fitted in the corresponding gas exhaust ports24, airtightness between the electric rechargeable cells20and the gas exhaust member80can be ensured further.

Next, referring toFIGS. 11 and 12, a gas exhaust member90will be described which is a first modified example made to the gas exhaust member80of the embodiment.

A gas exhaust member90of this modified example has a plurality of branch pipes91and one exhaust pipe92. The plurality of branch pipes91are connected, respectively, to gas exhaust ports24which are disposed in a zigzag fashion in the direction in which the electric rechargeable cells20are stacked. The plurality of branch pipes91are connected to the exhaust pipe92in such a manner as to be collected thereinto. A leading end portion of the exhaust pipe92is led to the outside of the battery system from the gas exhaust member inserting hole51formed in the end face plate50.

Next, referring toFIGS. 13 and 14, a gas exhaust member100will be described which is a second modified example made to the gas exhaust member80of the embodiment.

A gas exhaust member100of this modified example has a plurality of conduits101and two independent exhaust pipes102,102. The plurality of conduits101are connected, respectively, to gas exhaust ports24which are disposed in a zigzag fashion in the direction in which the electric rechargeable cells20are stacked. The plurality of conduits101which are arranged in two rows are connected to two independent exhaust pipes102,102, respectively. In addition, in this modified example, in order for the two exhaust pipes102,102to be led to the outside of the battery system, two gas exhaust portion inserting holes51are formed in the end face plate50.

Thus, as has been described heretofore, according to the battery system10of the embodiment, the battery system10includes the electric rechargeable cells20which each have the gas exhaust port24, as well as the positive electrode terminal22and the negative electrode terminal23which are disposed in such a manner as to hold the gas exhaust port24therebetween. The battery system10also includes the gas exhaust member80which is connected to the gas exhaust ports24and the voltage control circuit70which is provided in the position confronting the gas exhaust member80and between the positive electrode terminals22and the negative electrode terminals23and is connected to the positive electrode terminals22and the negative electrode terminals23of the electric rechargeable cells20so as to control the voltages of the individual electric rechargeable cells20. Therefore, the positive electrode terminals22and the negative electrode terminals23of the electric rechargeable cells20and the voltage control circuit70can be connected to each other over a short distance, thereby making it possible to miniaturize the battery system10.

In addition, according to the battery system10of the embodiment, the battery system10includes the electric rechargeable cells20which each have the gas exhaust port24, as well as the positive electrode terminal22and the negative electrode terminal23which are disposed in such a manner as to hold the gas exhaust port24therebetween. The battery system10also includes the gas exhaust member80which is connected to the gas exhaust ports24, the partition holding member40which establishes the partitions between the gas exhaust member80and the positive electrode terminals22and the negative electrode terminals23in such a manner as to cover the gas exhaust member80and the positive electrode terminals22and the negative electrode terminals23and on which the conductive members11are provided and the voltage control circuit70attached to the outer surface side of the partition holding member40in the position which confronts the gas exhaust member80for controlling the voltages of the individual electric rechargeable cells20. Therefore, not only the space defined between the positive electrode terminals22and the negative electrode terminals23is used effectively but also the partition holding member40has the layered construction. Thus, the electric rechargeable cells20, the respective terminals22,23of the electric rechargeable cells20, the conductive members11, the voltage control circuit70and the gas exhaust member80can be integrated into a compact unit. In addition, since the voltage control circuit70is incorporated within the battery system10, the assembling properties of the battery system10can be increased, thereby making it possible to realize the miniaturization of the battery system10.

In addition, according to the battery system10of the embodiment, the positive electrode terminals22and the negative electrode terminals23are both the plate-shaped members and are disposed in such a manner that the plate surfaces thereof confront each other. Therefore, torque received by the electric rechargeable cells20when the conductive members11are connected to the electric rechargeable cells20in such a manner as to expand between the adjacent electric rechargeable cells20can be made to be borne by the nut members47of the partition holding member40when compared with a battery system in which terminals of electric rechargeable cells each have a round shaft shape. Thus, the electric rechargeable cell can be made compact in terms of strength, thereby making it possible to realize the miniaturization of the battery system.

Additionally, according to the battery system10of the embodiment, the first penetrating holes25are formed respectively in the positive electrode terminals22and the negative electrode terminals23and the second penetrating holes11aare provided respectively at both the end portions of the conductive members11so that the positive electrode terminals22. The negative electrode terminals23and the conductive members11are fixed together by the fastening bolts13which are inserted into the first penetrating holes25and the second penetrating holes11a. Therefore, the conductive members11can easily be fastened to the positive electrode terminals22and the negative electrode terminals23.

In addition, according to the battery system10of the embodiment, the first penetrating holes25of the positive electrode terminals22and the negative electrode terminals23are formed into the elongated hole shape. By the adjacent conductive members11being arranged in a zigzag fashion in the direction in which the electric rechargeable cells20are stacked, a larger bolt can be used, thereby making it possible to increase the assembling properties of the battery system10.

Additionally, according to the battery system10of the embodiment, the cell holder30for holding the electric rechargeable cells20is provided and the projecting portions are formed on the cell holder30for forming the gaps34between the electric rechargeable cells20and the cell holder30through which cooling air is caused to flow. Therefore, the electric rechargeable cells20can be cooled with good efficiency.

In addition, according to the battery system10of the embodiment, the nut members47which are conductive and into which the fastening bolts13are screwed are provided and the nut members47and the voltage control circuit70are electrically connected. Therefore, the positive electrode terminals22and the negative electrode terminals23of the electric rechargeable cells20and the voltage control circuit70can be connected to each other over a short distance, thereby making it possible to reduce the possibility that a problem such as short circuit occurs.

Additionally, according to the battery system10of the embodiment, the gas exhaust ports24are disposed in a row in the direction in which the electric rechargeable cells20are stacked and the gas exhaust member80is formed such that gases from the gas exhaust ports24are divided so as to flow into the two exhaust pipes82via the plurality of dividing pipes81. Therefore, even in the event that gases are produced within the electric rechargeable cells20, the pressure under which the gases are produced can be dispersed through the two divided exhaust pipes82into which the gases so produced are designed to be divided to flow, thereby making it possible to expel the gases so produced to the outside of the battery system10with good efficiency.

In addition, according to the battery system10of the embodiment, the gas exhaust ports24are disposed in the zigzag fashion in the direction in which the electric rechargeable cells20are stacked and the gas exhaust member90is formed such that gases from the gas exhaust ports24are collected into the one exhaust pipe92. Therefore, even in the event that gases are produced within the electric rechargeable cells20, the pressure under which the gases are produced can be dispersed through the exhaust pipe92into which the gases so produced are designed to be collected to flow, thereby making it possible to expel the gases so produced to the outside of the battery system10with good efficiency.

Additionally, according to the battery system10of the embodiment, the gas exhaust ports24are disposed in the plurality of rows in the direction in which the electric rechargeable cells20are stacked and the gas exhaust member100is formed such that gases from the gas exhaust ports24of the plurality of rows are designed to be collected by the row to flow into the exhaust pipes102which are disposed correspondingly to the respective rows of gas exhaust ports24. Therefore, even in the event that gases are produced within the electric rechargeable cells20, the pressure under which the gases are produced can be dispersed through the exhaust pipes102which are disposed correspondingly to the respective rows, thereby making it possible to expel the gases so produced to the outside of the battery system10with good efficiency.

Furthermore, according to the battery system10of the embodiment, there are provided the end face plates50which are attached, respectively, to the end faces of the cell holder30and the partition holding member40and the through-hole fastening members60which extend through the cell holder30and the partition holding member40, as well as the end face plates50in such a manner as to fasten the cell holder30, the partition holding member40and the end face plates50together. Therefore, the strong and rigid housing can be obtained as the whole of the battery system, thereby making it possible to increase the durability of the battery system10.

Note that the invention is not limited to the embodiment which has been illustrated heretofore and hence can be altered or modified as required without departing form the spirit and scope of the invention.

For example, while in the embodiment, the partition holding member40is made up of the side bodies41and the alternately grooved and ridged plate portion42which are molded into the integral unit, the invention is not limited thereto. Hence, a partition holding member may be adopted which is made by connecting and combining together a plurality of separately molded constituent members.