Battery cartridge-connecting system for battery module

A battery cartridge-connecting system for battery modules including bus bars, each of which includes a plate-shaped bar body, coupling parts, and electrical connection parts; a base plate, to which the bus bars are easily mounted; and a printed circuit board (PCB), which is easily coupled to the bus bars and is mounted to the base plate in a compact structure. The present invention also provides a battery module and a medium- or large-sized battery system including the battery cartridge-connecting system.

FIELD OF THE INVENTION

The present invention relates to a battery cartridge-connecting system for battery modules, and, more particularly, to a battery cartridge-connecting system for battery modules, comprising: bus bars, each of which includes a plate-shaped bar body, coupling parts, and electrical connection parts; a base plate, to which the bus bars are easily mounted; and a printed circuit board (PCB), which is easily coupled to the bus bars and is mounted to the base plate in a compact structure, and a battery module and a medium- or large-sized battery system including the same.

BACKGROUND OF THE INVENTION

Recently, a secondary battery, which can be charged and discharged, has been widely used as an energy source for wireless mobile devices. Also, the secondary battery has attracted considerable attention as a power source for electric vehicles and hybrid electric vehicles, which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuel.

Small-sized mobile devices use one or several small-sized cells for each device. On the other hand, medium- or large-sized devices, such as vehicles, use a medium- or large-sized battery system having a plurality of cells electrically connected with each other because high output and large capacity is necessary for the medium- or large-sized devices.

As the unit cell for the medium- or large-sized battery system is widely used a pouch-shaped secondary cell, which is generally packaged in a battery case made of a laminate sheet consisting of aluminum and polymer resin, and therefore, the mechanical strength of the pouch-shaped secondary cell is not high. For this reason, a plurality of unit cells are mounted in a battery cartridge, where the unit cells are connected in series or parallel, and a plurality of battery cartridges are electrically connected with each other to constitute a battery module.

A battery module widely used for hybrid electric vehicles has a closed structure in which an electrolyte cannot leak from each unit cell (secondary cell). That is to say, the closed type battery module has an advantage of preventing leakage of the electrolyte. However, the closed type battery module has problems in that heat generated in unit cells is accumulated, and the accumulated heat accelerates the deterioration of the cells and that a small or large number of unit cells are overheated when they are operated abnormally, and therefore, the unit cells may catch on fire or explode. Lithium-ion secondary cells or lithium-ion polymer secondary cells, which are currently generating much interest in the potential uses of unit cells, generate heat while the secondary cells are charged and discharged. When such heat is continuously accumulated in the unit cell, the deterioration of the unit cell is accelerated, and furthermore, the unit cell may catch on fire or explode.

The applicant of the present application developed a battery cartridge and a battery module having a novel structure to solve the above-mentioned problems, which have been filed to the Korean Intellectual Property Office and accorded Korean Patent Application No. 2004-111699.

The battery cartridge and the battery module described in the above-mentioned patent application, have several features of stably mounting unit cells having low mechanical strength, effectively removing heat from the unit cells, and preventing the unit cells from overheating when the unit cells are operated abnormally, thereby improving the service life and safety of the unit cells. Also, this battery module can be manufactured generally in a compact structure, and therefore, this battery module is preferably used to provide a small-sized high-output, large-capacity battery module or battery system.

On the other hand, it is required that the electrical connection between the unit cells and the coupling of the unit cells with other components be carried out in a small space so as to manufacture the compact battery module or battery system. As a result, it is possible that short circuits occur, and it is difficult to accomplish mechanical coupling by welding or using bolts and nuts. For this reason, there has been proposed a method of accomplishing the electrical connection between the unit cells in a contact fashion using elastic members, such as springs. In this conventional method, however, the mechanical strength and the resistance to vibrations are low, and the elastic members may easily corrode with the result that the contact resistance is increased. Furthermore, the connected parts are easily separated from each other. These problems also occur at a printed circuit board (PCB), which is mounted to measure the voltage and the temperature of the unit cells.

SUMMARY OF THE INVENTION

Specifically, it is a first object of the present invention to provide a battery cartridge-connecting system that is capable of easily accomplishing the electrical connection and the mechanical coupling in a compact-structured battery module or battery system, the battery cartridge-connection system having excellent electrical characteristics, such as electric resistance at the connected parts, after the electrical connection is completed, and excellent mechanical strength to external impacts or vibrations after the mechanical coupling is completed. The excellent electrical characteristics and the excellent mechanical strength may be also applied to the mounting and the electrical connection of a printed circuit board (PCB), which is provided to electrically connect battery cartridges having unit cells mounted therein and measure the voltage and temperature of the unit cells.

It is a second object of the present invention to provide a battery cartridge-connecting system that is capable of preventing a risk of an engineer or a user being exposed to the electrical short circuits when a battery module or a battery system is manufactured or when the battery module or the battery system is repaired. According to the present invention, the occurrence of short circuits is prevented. Consequently, the defective product rate is lowered, and therefore, the manufacturing efficiency is highly improved.

It is a third object of the present invention to provide a battery module including the above-described battery cartridge-connecting system, whereby the battery module is constructed in a compact structure while the electrical connection is stable and the mechanical characteristics, including durability, are excellent, and a battery system including such a battery module.

In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a battery cartridge-connecting system for battery modules, comprising: bus bars, which are members for electrically connecting battery cartridges, each of the bus bars including a plate-shaped bar body constructed to be in surface contact with electrode terminals of a battery, a coupling part formed by bending at least a portion of each end of the plate-shaped bar body, and electrical connection part formed by bending at least a portion of each end of the plate-shaped bar body, wherein each of the coupling parts is provided with a coupling groove, in which a corresponding coupling member formed at a base plate is engaged, and the electrical connection parts are formed in the shape of a protrusion, which can be securely inserted into a corresponding part of a printed circuit board (PCB); the base plate, which is a member for allowing the plurality of bus bars to be attached thereto, the base plate including a plurality of openings, into which the bus bars are securely inserted, the coupling members being formed at the openings such that the coupling members are engaged in the coupling grooves of the bus bars; and the printed circuit board (PCB), which is a member electrically connected to the plurality of bus bars, the printed circuit board (PCB) having connection holes, through which the protruding electrical connection parts of the bus bars are securely inserted.

With the battery cartridge-connecting system according to the present invention, the plurality of bus bars can be easily mounted to the base plate in a mechanical coupling fashion, and the printed circuit board (PCB) can be electrically connected to the bus bars with ease. Consequently, the mechanical stability at the coupled parts is excellent even though the structure of the battery module or the battery system is compact.

In a preferred embodiment of the present invention, each of the battery cartridges includes a pair of outer frame members (a, b) and an inner frame member (c) disposed between the outer frame members (a, b) such that a unit cell is mounted between the first unit cell between the first outer frame member (a) and the inner frame member (c) and another unit cell is mounted between the second outer frame member (b) and the inner frame member (c). According to circumstances, two or more unit cells are mounted between one of the outer frame members (a or b) and the inner frame member (c).

While the two unit cells are mounted in each of the battery cartridges, the electrode terminals of each unit cell protrude toward the upper ends of the frame members (a, b, c). In a preferred embodiment of the present invention, the inner frame member (c) is provided at a predetermined position corresponding to one of the electrode terminals (the cathode terminal or the anode terminal) of the upper end thereof with a skirt, which extends along the corresponding electrode terminal, and the base plate is provided at a predetermined position corresponding to the skirt with a groove, in which the skirt is engaged. This structure of the skirt and the groove prevents occurrence of electrical short circuits, which may be caused by incorrect connection of the cathode and the anode when the base plate, to which the bus bars are mounted, is assembled with the battery cartridges, and accurately sets the coupling positions of the base plate and the battery cartridges.

Preferably, the electrode terminals of the unit cells mounted in the battery cartridges and the bus bars mounted to the base plate are securely attached to each other by welding or soldering after the assembly of the battery cartridges and the base plate is completed, whereby the coupling and the electrical connection between the electrode terminals and the bus bars are more securely accomplished. More preferably, the electrode terminals of the unit cells and the bus bars are securely attached to each other by welding, such as laser welding or resistance welding.

Preferably, the outer frame members (a, b) are provided at the upper ends thereof with locating parts, at which the electrode terminals of the unit cells are located while being bent, and wherein the outer frame members are provided under the locating parts thereof with depressions, which extend in the lateral direction of the outer frame members, and the locating parts have pluralities of welding grooves, which communicate with the depressions, whereby the welding operation is easily carried out. Consequently, when a welding operation, for example, a resistance welding operation (or a spot welding operation) is carried while the plurality of battery cartridges are stacked, one welding tip is connected to the lower ends of the electrode terminals on the locating parts through the depressions and the welding grooves, and another welding tip is connected to the upper ends of the bus bars. It has been proved that the welding grooves are helpful even when a laser welding operation is carried out at the upper ends of the bus bars.

In a preferred embodiment of the present invention, each of the battery cartridges further has a thermistor for measuring the temperature of the unit cells. The thermistor may be mounted between the unit cells through a groove formed between the anode terminal locating part and the cathode terminal locating part of the inner frame member (c).

The coupling between the frame members is not particularly restricted. For example, the coupling between the frame members may be accomplished by various coupling methods, such as bolts/nuts, rivets, welding, adhesive, a male and female screw coupling member or structure.

Also, the material for the frame members is not particularly restricted. The frame members may be made of various materials, such as plastic resin or metal. In the case of using a conductive material, such as metal, however, it is necessary to electrically insulate the exposed parts of electrode leads.

The unit cells mounted in the cartridges are secondary cells, which can be charged and discharged. Preferably, a rectangular secondary cell or a pouch-shaped secondary cell, which can be stacked with high integration, is used as the unit cell. Preferably, the pouch-shaped cell is normally used as the unit cell.

Each of the unit cells has a cathode, an anode, a separator, and an electrolyte mounted in a sealed cell case. Each of the unit cells has a jelly-roll type structure in which an electrode assembly including a minute porous separator between a thin film-shaped cathode and anode is wound, or a stack type structure in which fullcells or bicells of anode/separator/cathode are sequentially stacked one on another. Active materials, which are applied to the cathode and the anode, are not particularly restricted. Preferably, the cathode active material consists of lithium manganese-based oxide having high safety, and the anode active material consists of carbon. The preferable unit cell is a lithium-ion cell or a lithium-ion polymer cell.

As described above, each of the bus bars includes the plate-shaped bar body, the coupling parts, and the electrical connection parts. The coupling parts and the electrical connection parts are formed by appropriately bending opposite ends of the plate-shaped bar body. Preferably, the coupling parts are bent two times or more such that the coupling parts are elastically engaged in the openings of the base plate with ease when the bus bars are mounted in the openings of the base plate.

The bending direction of the coupling parts is identical to that of the electrical connection parts, and the width of the coupling parts is greater than that of the electrical connection parts, whereby the coupling force between the bus bars and the openings of the base plate is provided by the coupling parts when the bus bars are mounted in the openings of the base plate.

The base plate is attached to the upper ends of the plurality of battery cartridges, which are stacked, i.e., to the electrode terminals, and the base plate includes openings (an upper opening array), in which bus bars interconnecting one-side electrode terminals of the stacked battery cartridges are mounted, and openings (a lower opening array), in which bus bars interconnecting the other-side electrode terminals of the stacked battery cartridges are mounted, the openings of the upper opening array and the openings of the lower opening array being alternately arranged, which will be described hereinafter in detail. As previously described, one of the opening arrays is provided with grooves, in which the skirts of the battery cartridges are engaged, and the other opening array is provided with corresponding skirts.

At the printed circuit board (PCB) is formed a circuit for providing information about the voltage and the temperature of the unit cells to a battery management system (BMS), which includes a circuit for maintaining potential difference between the unit cells at an appropriate level and preventing overcharge, overdischarge, and overcurrent. The circuit of the printed circuit board (PCB) is formed on a plate-shaped material consisting of a denatured epoxy resin composite. The circuit is electrically connected to the respective bus bars. As previously described, the connection holes of the printed circuit board (PCB), through which the electrical connection parts of the bus bars are securely inserted, are formed at predetermined positions corresponding to the bus bars. In a preferred embodiment of the present invention, the connection holes of the printed circuit board (PCB) are formed through protrusions formed at sides of the printed circuit board (PCB). Preferably, the electrical connection parts of the bus bars are inserted through the connection holes of the printed circuit board (PCB), and then the electrical connection parts are securely attached to the printed circuit board (PCB) by soldering. In the case that a thermistor is mounted to each of the battery cartridges, connectors, which are connected to the thermistors, are formed at the printed circuit board (PCB). It goes without saying that the connection holes and the connectors for thermistors are electrically connected to the battery management system (BMS) through the circuit formed on the printed circuit board (PCB).

In accordance with another aspect of the present invention, there is provided A battery module including the above-described battery cartridge-connecting system.

Specifically, the battery module according to the present invention comprises: a battery cartridge assembly including two or more battery cartridges; a box-shaped module case having an open front part, through which the battery cartridge assembly is inserted, and an inner space, in which the battery cartridge assembly is mounted; and a battery cartridge-connecting system coupled to the front open part of the case.

The battery module according to the present invention is generally compact, and the structural stability of the battery module is excellent. The battery module can be manufactured in an open type structure in which heat generated from unit cells while the unit cells are charge and discharged is effectively removed even though the battery module has the compact structure. The details of the battery module manufactured in the open type structure are described in Korean Patent Application No. 2004-111699, the disclosure of which is incorporated herein by reference.

The plurality of battery cartridges are inserted into the module case, the battery cartridge-connecting system (the base plate having the bus bars and the printed circuit board (PCB) mounted thereto) is coupled to the open front part of the module case, and the electrode terminals of the battery cartridges and bus bars are securely attached to each other by welding.

In a preferred embodiment of the present invention, the battery module further comprises: a safety plate for covering the outer surface of the base plate, the safety plate having a plurality of inserting parts, which have a size and a shape suitable to be inserted into the openings of the base plate. The inserting parts of the safety plate serve to improve the tight contact between the bus bars and the electrode terminals of the battery cartridges, to prevent the separation of the bus bars when external impacts are applied to the battery module, and prevent the possibility of short circuits.

After the assembly process is completed, the bus bars are partially exposed from the outer surface of the base plate. Preferably, an additional safety plate for covering the outer surface of the base plate may be further provided.

In accordance with yet another aspect of the present invention, there is provided a high-output, large-capacity battery system (or battery pack) including a plurality of battery modules electrically connected with each other. Preferably, a coupling member for accomplishing effective coupling between the battery modules may be further included.

The battery system according to the present invention may be used for high-output, large-capacity battery systems. Preferably, the battery system is used for battery systems of electric vehicles or hybrid electric vehicles. More preferably, the battery system is used for battery systems of hybrid electric vehicles.

<Description of Main Reference Numerals of the Drawings>100: battery cartridge200: unit cell300: bus bar400: base plate500: PCB600: module case700: safety plate800: battery module

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1is a perspective view typically illustrating a battery cartridge according to a preferred embodiment, which can be used in the present invention.

Referring toFIG. 1, the battery cartridge100comprises: a pair of outer frame members110and120; and an inner frame member130disposed between the outer frame members110and120. The details of the frame members110,120, and1300are disclosed in Korean Patent Application No. 2004-111699, which has been filed in the name of the applicant of the present application.

Two unit cells (not shown) are mounted in a hollow part between the first outer frame member110and the inner frame member130and in another hollow part between the second outer frame member120and the inner frame member130, respectively. The frame members110,120, and130include pluralities of supporting bars140, which traverse the hollow parts of the frame members110,120, and130in the lateral direction of the frame members110,120, and130for more stably supporting the unit cells between the first outer frame member110and the inner frame member130and between the second outer frame member120and the inner frame member130.

At the inner frame member130is mounted a thermistor150for measuring the temperature of the unit cells. The structure of the inner frame member130is shown inFIG. 2.

Referring back toFIG. 1, the outer frame members110and120are provided at the upper ends thereof with locating parts112and114, respectively, at which electrode terminals of the unit cells, which are mounted between the first outer frame member110and the inner frame member130and between the second outer frame member120and the inner frame member130, are located while being bent. At the outer frame members110and120under the locating parts112and114are formed depressions115, which extend in the lateral direction of the outer frame members110and120. At the locating parts112and114are also formed pluralities of welding grooves116, which communicate with the depressions115. Consequently, when a welding operation, for example, a resistance welding operation is carried out to bus bars (not shown) and electrode terminals (not shown) on the locating parts112and114during the assembly, one welding tip160can be connected to the lower ends of the electrode terminals through the depressions115and the welding grooves116.

A skirt protrudes from one of the locating parts112and114formed at the upper end of the battery cartridge110, i.e., the locating part112. More specifically, as shown inFIG. 2, the skirt117protrudes from one side of a locating part132formed at the upper end of the inner frame member130such that the skirt117extends in the lateral direction of the inner frame member130, which will be described below in detail with reference toFIG. 3.

FIG. 3is a perspective view typically illustrating unit cells mounted in the battery cartridge ofFIG. 1.

Referring toFIG. 3, electrode terminals210and220of a unit cell200, which is mounted between the first outer frame member110and the inner frame member130, and electrode terminals211and221of another unit cell201, which is mounted between the second outer frame member120and the inner frame member130are located at the locating parts112and114, which are formed at the upper end of the battery cartridge, while being bent. Specifically, the electrode terminals210and220are bent upward while the electrode terminals221and221are bent downward, as shown in the drawing.

For example, on the assumption that the electrode terminal210of the unit cell200is the cathode terminal, and the electrode terminal220of the unit cell200is the anode terminal, the electrode terminal211of the unit cell201is the anode terminal, and the electrode terminal221of the unit cell201is the cathode terminal. Consequently, when the two unit cells200and201are connected in series with each other, the anode terminal220of the unit cell200and the cathode terminal221of the unit cell201are electrically connected with each other via a bus bar (not shown), the cathode terminal210of the unit cell200is connected to the cathode terminal of a unit cell A of a neighboring battery cartridge (not shown), and the anode terminal211of the unit cell201is connected to the cathode terminal of another unit cell B of the neighboring battery cartridge (not shown).

Consequently, the electrode terminals220and221, which are located at one of the locating parts112and114of the battery cartridge100, i.e., the locating part114, while being bent, are directly connected with each other. On the other hand, the electrode terminals210and211, which are located at the other locating part112of the battery cartridge100while being bent, are not directly connected with each other but are connected to the electrode terminals of the neighboring battery cartridge. At this time, the skirt117disposed on the locating part112prevents the electrode terminals210and211, which are bent in opposite directions at the opposite sides of the skirt117, from being directly connected with each other by the bus bar, whereby the occurrence of short circuit due to the incorrect assembly is prevented.

FIG. 4is a perspective view typically illustrating a bus bar according to a preferred embodiment, which can be used in the present invention.

Referring toFIG. 4, the bus bar300includes a coupling part320and an electrical connection part330, which are formed at each end of a plate-shaped bar body310. The lower surface of the plate-shaped bar body310is connected to the electrode terminals (seeFIG. 3) disposed at the upper end of the battery cartridge, and, afterwards, the electrode terminals are securely attached to the plate-shaped bar body310by welding or soldering. The coupling parts320and the electrical connection parts330are bent in the direction opposite to the surface of the plate-shaped bar body310where the electrode terminals are securely attached to the plate-shaped bar body310.

The structure of the coupling parts320and the electrical connection parts330will be described in more detail with reference toFIG. 5. The coupling parts320are formed by bending the ends of the plate-shaped bar body310two times. Specifically, the ends of the plate-shaped bar body310are bent upward by 90 degrees, and then the halves of the bent ends of the plate-shaped bar body310are bent downward by 180 degrees. Consequently, when the bus bar300is mounted to a base plate (not shown), more elastic coupling force is provided by the bus bar, and the bus bar300can be more easily inserted into the opening of the base plate by the bent upper end surfaces321of the bus bar300. In the center of each coupling part320is formed a coupling groove322, in which a coupling member (not shown) formed at the opening of the base plate is engaged.

The electrical connection parts330, which have a length less than that of the coupling parts320and which are partially formed at the opposite ends of the plate-shaped bar body310, protrude upward while having a small width. These protruding connection parts330are easily inserted into the corresponding parts of a printed circuit board (PCB), whereby the electrical connection is accomplished.

FIG. 6is a perspective view typically illustrating a base plate according to a preferred embodiment, which can be used in the present invention.

Referring toFIG. 6, the base plate400is a thick plate-shaped member including a plurality of openings410, in which the bus bars (not shown) are mounted, respectively. The openings410are rectangular through-holes having a size corresponding to the bus bars. At the opposite ends of the inside surface of each opening410are formed coupling members420, which are engaged in the coupling grooves322formed at the coupling parts320of the bus bar (seeFIG. 5).

The openings410of the base plate400are classified into an upper opening array401, in which bus bars interconnecting one-side electrode terminals of stacked battery cartridges are mounted, and a lower opening array402, in which bus bars interconnecting the other-side electrode terminals of the stacked battery cartridges are mounted. The openings of the upper opening array401and the openings of the lower opening array402are alternately arranged because of the connecting positions of the bus bars when the electrode terminals are electrically connected with each other, as previously described with reference toFIG. 3. Also, skirts430are formed on the partitions between the openings of the upper opening array401, and grooves440are formed on the partitions between the openings of the lower opening array402. The skirt117disposed on the locating part112formed at the upper end of the battery cartridge100(seeFIG. 3) is engaged in the corresponding groove440of the lower opening array402.

Between the upper opening array401and the lower opening array402is disposed a bridge450, which is depressed such that a printed circuit board (PCB) (not shown) is located on the bridge450. On a portion of the bridge is formed a plurality of grooves, in which the connectors of thermistors (not shown) are located.

FIG. 7is a perspective view typically illustrating a printed circuit board (PCB) according to a preferred embodiment, which can be used in the present invention, with a plurality of bus bars being connected to the printed circuit board (PCB).

Referring toFIG. 7, the printed circuit board (PCB)500is a plate-shaped member. The printed circuit board (PCB)500has protrusions510formed at predetermined positions where the bus bars300are connected to the printed circuit board (PCB)500. In each protrusion510is formed a connection hole512, through which the connection part330of the corresponding bus bar300is inserted. Consequently, the connection between the bus bars300and the printed circuit board (PCB)500is accomplished by simply inserting the connection parts300through the connection holes512. This connection is stably maintained even when the external forces, for example, impacts or vibrations, are applied to the assembly of the printed circuit board (PCB)500and the bus bars300. The mechanical and electrical coupling degree at the connected parts of the assembly of the printed circuit board (PCB)500and the bus bars300may be increased by soldering. Information, such as voltage, of the unit cells (not shown) is transmitted to a circuit of the printed circuit board (PCB)500through the connection parts330of the bus bars300, and is then transmitted to a battery management system (BMS) (not shown), where the unit cells are controlled based on the information transmitted to the battery management system (BMS).

The printed circuit board (PCB)500is provided at the front and rear surfaces thereof with connectors530and540for electrical connection with the battery management system (BMS). For example, the connector530may be a connector, to which a communication cable between a slave battery management system (BMS) and a master battery management system (BMS) is connected, and the connector540may be a connector, through which voltage and temperature signals are transmitted to the slave battery management system (BMS). The positions of the connectors530and540may be reversed. According to circumstances, at least one of the connectors530and540may be removed. Consequently, the electrical connection between the printed circuit board (PCB)500and the battery management system (BMS) can be accomplished in various constructions. These constructions must be interpreted to fall within the scope of the present invention.

FIGS. 8 and 9are typical perspective views respectively illustrating the front and rear surfaces of the base plate with the bus bars and the printed circuit board (PCB) ofFIG. 6being mounted to the base plate ofFIG. 5.

Referring toFIGS. 8 and 9, the coupling members420of the base plate400are engaged into the coupling grooves322of the bus bars300, whereby the bus bars300are mounted to the base plate400. In the state that the bus bars300are mounted to the base plate400, the coupling parts320of the bus bars300are exposed from the front surface (or the outer surface) of the base plate400through the openings410, and the plate-shaped bar bodies310of the bus bars300are exposed from the rear surface (or the inner surface) of the base plate400. The electrode terminals of the battery cartridges100(seeFIG. 3) are connected to the rear surfaces of the plate-shaped bar bodies310of the bus bars300. It is preferable that the electrode terminals of the battery cartridges100are securely attached to the plate-shaped bar bodies310of the bus bars300by laser welding or resistance welding. Because of the elastic engagement between the coupling members420of the base plate400and the coupling grooves322of the bus bars300, the plate-shaped bar bodies310of the bus bars300are connected to the electrode terminals of the battery cartridges in a somewhat pressurized state when a battery module (not shown) having a plurality of battery cartridges mounted therein is coupled to the base plate400, whereby conditions preferable to perform the welding or the soldering are formed.

The printed circuit board (PCB)500is attached to the rear surface of the base plate400(The printed circuit board500is indicated by a dotted line inFIG. 8) such that the printed circuit board (PCB)500is located on the bridge450of the base plate400. The connectors540, which are connected to the thermistors150(seeFIG. 1), are formed at the printed circuit board (PCB)500.

As described above in detail with reference toFIGS. 1 to 9, the assembly can be easily carried out in a specific structure by using the battery cartridge-connecting system according to the present invention. Furthermore, the mechanical and electrical coupling is excellent in the assembled state, and therefore, the coupling is stably maintained even when the external forces, for example, impacts or vibrations, are applied to the assembly.

FIG. 10is a perspective view typically illustrating a box-shaped module case, which is used to manufacture a battery module according to a preferred embodiment of the present invention, andFIG. 11is a perspective view typically illustrating a battery module according to a preferred embodiment of the present invention.

Referring toFIGS. 10 and 11, the module case600has an open front part610and an inner space620, in which a plurality of battery cartridges100are mounted. The module case600is formed approximately in the shape of a box. The module case600is provided at the upper end630thereof with a plurality of through-channels660. Also, the module case600is provided at the lower end640thereof with a plurality of through-channels660. The through-channels660formed at the upper and lower ends630and640of the module case600communicate with the inner space620of the module case600. According to circumstances, the through-channels660may be further formed at the rear surface670of the module case600. To the side surface650of the module case600is attached a battery management system (not shown).

The base plate400, to which the bus bars300and the printed circuit board (PCB) (not shown) are attached, is mounted at the open front part610of the module case600while the plurality of battery cartridges100are mounted in the module case600, and then the base plate400is securely assembled to the module case600by means of bolts and nuts.

After the assembly is completed, welding tips (not shown) are introduced through introduction holes632formed at the upper end630of the module case600to carry out the resistance welding of the bus bars300and the electrode terminals. When the resistance welding is carried out, other welding tips (not shown) are connected to the outer surfaces of the bus bars300exposed through the openings410of the base plate400. According to circumstances, it is possible to directly carry out laser welding to the bus bars300exposed through the openings410of the base plate400. Since the introduction holes632, through which the welding tips are introduced, communicate with the depression115of the battery cartridge100, which is shown inFIG. 1, the welding tips can be easily connected to the rear surfaces of the electrode terminals through the depression115and the welding grooves116, as described with reference toFIG. 1.

According to circumstances, as shown inFIG. 12, a safety plate may be attached to the outer surface of the base plate400.

Referring toFIG. 12, the safety plate700is formed in a shape similar to the base plate400, and the safety plate700includes a plurality of inserting parts710, which have a size and a shape suitable to be inserted into the openings410of the base plate400. As shown in the drawing, the inserting parts710are inserted into the openings410of the base plate400, whereby the tight contact between the bus bars300and the battery cartridges (not shown) is improved, the separation of the bus bars300is prevented when external impacts are applied to the battery module, and the possibility of short circuits, which may be caused due to the exposure of the bus bars300, is prevented.

Referring back toFIG. 11, a battery module800is completed through the above-described assembly process. The battery module800generally has a compact size, and therefore, the battery module800provides high output for each unit volume. Furthermore, the battery module800provides high mechanical and electrical safety against external impacts.

A plurality of battery modules800having the above-described construction, are electrically connected with each other to manufacture a high-output, large-capacity battery system. In this case, the electrical connection between the battery modules800is accomplished by a connecting member810coupled to one side of the base plate400. This battery system is very useful as a power source for electric vehicles, especially, hybrid electric vehicles.

INDUSTRIAL APPLICABILITY

As apparent from the above description, the battery cartridge-connecting system according to the present invention easily accomplishes the electrical connection and the mechanical coupling in the compact-structured battery module or battery system. In addition, the battery cartridge-connection system has excellent electrical characteristics, such as electric resistance at the connected parts, after the electrical connection is completed, and excellent mechanical strength to external impacts or vibrations after the mechanical coupling is completed. Furthermore, the battery cartridge-connecting system prevents a risk of an engineer or a user being exposed to the electrical short circuits when the battery module or the battery system is manufactured or when the battery module or the battery system is repaired.