JP4513451B2 - Assembled battery - Google Patents

Description

  The present invention relates to an assembled battery that can apply a uniform pressure to each flat battery constituting a battery stack.

  In recent years, in response to growing environmental awareness, there is a movement to shift the power source of automobiles from an engine using fossil fuel to a motor using electric energy. For this reason, the technology of the battery that serves as a power source for the motor is also rapidly developing.

An automobile is desired to be equipped with a battery that is small and light and can be charged and discharged with a large amount of electric power and has excellent vibration resistance. In response to these demands, recently, as shown in Patent Document 1 below, an assembled battery in which a plurality of flat batteries are stacked in the thickness direction has been developed.
JP 2001-236937 A

  However, in such a conventional assembled battery, a plurality of stacked flat batteries are sandwiched by a pair of restraining plates from both sides (upper and lower) in the stacking direction, and restrained by bolts and nuts that connect the corners of the restraining plates. Since the flat plates are tightened in the direction to bring them close to each other, surface pressure is applied to each flat battery, so that the entire surface of the flat battery is caused by distortion of the restraint plate and localized tightening force. There is a problem that it is difficult to give a uniform surface pressure to the surface.

  It is well known that surface pressure is a factor that greatly affects the life of flat batteries. In order to provide a uniform surface pressure, the thickness of the restraint plate can be increased to increase its rigidity, or the number of bolts and nuts that connect the restraint plate can be increased. Neither method can be adopted because the problem arises that the assembly efficiency is worsened against the demands of the system. In addition, in order to provide a uniform surface pressure, it is necessary to individually adjust the tightening force by the bolts and nuts, so that there is also a problem that workability and maintainability are poor in this respect.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an assembled battery that can apply a uniform pressure to each flat battery constituting the battery stack. And

In order to achieve the above object, an assembled battery according to the present invention is applied to a battery stack in which a plurality of flat batteries are stacked in the thickness direction, and flat batteries positioned at both ends of the battery stack in the stacking direction. A set of pressure plates in contact with each other, a set of pressure application members sandwiching the set of pressure plates from opposite side surfaces of the battery stack, and the set of pressure application members connected to each other. A connecting member capable of biasing the applying members toward each other, and when the pressurizing members are brought close to each other by the connecting members, the pair of pressure plates move in a direction approaching each other. It is comprised so that the pressurization force to the said lamination direction can be provided to the said battery laminated body , The said pressurization provision which the said pressurization provision member and the said pressurization plate contact linearly or in several points | pieces Member or said On one of the contact surfaces at least one of the plate, the inclined portion for the moving in the direction toward the pressure plate each other when said pressing force applying member in proximity to each other are formed.

  The pressure applying members are connected to each other by a connecting member, and can be urged by the connecting member in directions close to each other. The pressure applying member sandwiches the respective pressure plates that are in contact with both ends of the battery stack in the stacking direction from the opposite side surfaces of the battery stack. When the pressure applying members are brought close to each other by the connecting member, the pair of pressure plates move in a direction approaching each other. For this reason, it is possible to uniformly apply pressure in the stacking direction to the battery stack.

  According to the assembled battery according to the present invention configured as described above, one set of pressure plates presses the battery stack as a whole, not locally, by one set of pressure applying members, so the number of parts is reduced. A uniform applied pressure can be applied to each flat battery, and an assembled battery that is compact and lightweight and has good assembly efficiency and maintainability can be provided.

  Below, the assembled battery concerning this Embodiment is demonstrated in detail based on drawing. FIG. 1 is a perspective view of the battery pack according to the present embodiment, and FIG. 2 is a side view of the battery pack of FIG.

  As shown in FIG. 1, an assembled battery 100 according to the present invention includes a heat sink 300, which is a battery unit 200 as a battery laminate in which a plurality of plate-shaped frames are laminated in the thickness direction. The battery unit 200 is sandwiched between 350 and pressed integrally from both sides in the frame stacking direction using the fixed plates 400 and 450 which are a set of pressure applying members, and are integrally held.

  In each frame 210, four flat batteries (specifically, rectangular laminated batteries) are arranged in parallel in the longitudinal direction, and the battery unit 200 is formed by stacking 24 frames 210 in the thickness direction. It is formed. Therefore, the assembled battery 100 is configured by stacking 24 flat batteries arranged in parallel in the thickness direction, each having 24 flat batteries, and has a total of 96 flat batteries. In addition, intermediate heat sinks 325A, 325B, and 325C are inserted every six sheets in the stacking direction of the frames, and the heat dissipation efficiency of the battery unit 200 is increased.

  As shown in FIG. 2, the heat sinks 300 and 350 having a function of radiating the heat of the battery unit 200 are in contact with flat batteries located at both ends of the battery unit 200 in the stacking direction. In the heat sinks 300 and 350, contact portions 310A, 310B, 360A, and 360B that are in contact with the fixing plates 400 and 450 are formed. The fixing plates 400 and 450 are rectangular plates and sandwich the heat sinks 300 and 350 from opposite side surfaces of the battery unit 200. The fixing plates 400 and 450 are formed with columnar portions 410A, 410B, 460A, and 460B that are in contact with the heat sinks 300 and 350, respectively. The columnar portions 410A and 410B of the fixed plate 400 and the contact portions 310A and 360A of the heat sinks 300 and 350, and the columnar portions 460A and 460B of the fixed plate 450 and the contact portions 310B and 360B of the heat sinks 300 and 350 are linear or plural respectively. It is comprised so that it may contact at the point. The fixing plates 400 and 450 are close to each other on the contact surfaces of the contact portions 310A, 310B, 360A, and 360B of the heat sinks 300 and 350 with respect to the columnar portions 410A, 410B, 460A, and 460B of the fixing plates 400 and 450, respectively. A tapered inclined portion for moving the heat sinks 300 and 350 in a direction close to each other is formed. The fixing plates 400 and 450 are connected to each other at the four corners thereof by bolts and nuts 475 (generic names of bolts 475A to 475D and nuts 480A to 480D) that function as connecting members extending substantially parallel to the side surface of the battery unit 200. Is done.

  When the nuts 480A to 480D are tightened to the bolts 475A to 475D, the fixing plates 400 and 450 are urged in a direction in which they are brought close to each other. When the fixing plates 400 and 450 move in the approaching direction, the pressing force in the direction in which the heat sinks 300 and 350 are brought close to each other by the contact surfaces of the fixing plates 400 and 450 and the heat sinks 300 and 350 (flat battery pressing direction). Is applied to the entire end surfaces of the heat sinks 300 and 350, and the heat sinks 300 and 350 are brought close to each other by the applied pressure, and an appropriate applied pressure in the stacking direction is applied to the battery unit 200.

  In the above description, the fixed plates 400 and 450 are rectangular plates. However, the fixed plates may have a rectangular frame shape instead of a plate shape. Further, in order to reduce the weight of the fixing plates 400 and 450, an appropriate number of holes may be opened in a place where there is no possibility of adversely affecting the rigidity.

  In the above description, the connecting member is constituted by a bolt and nut, but a part of the bolt may include a spring member that can expand and contract in the longitudinal direction. Further, the connecting member may be formed integrally with one of the fixed plates.

  FIG. 3 is an external view of a flat battery constituting the assembled battery 100.

  The flat battery 214 used in the present embodiment is a rectangular laminated secondary battery as shown in FIG. 3, and includes a laminated power generation element in which at least a positive electrode plate and a negative electrode plate are sequentially laminated, For example, it has a structure as disclosed in JP 2003-059486 A. The flat battery 214 uses a laminate film as its exterior material, and the built-in power generation element is sealed by heat-sealing the peripheral edge of the flat battery 214. Electrode tabs 215 </ b> A and 215 </ b> B are drawn out from both side surfaces in the longitudinal direction of the flat battery 214. The electrode tab 215A is a positive electrode tab, and is made of an aluminum thin plate having a thickness of about 0.2 mm, for example. On the other hand, the electrode tab 215B is a negative electrode tab, and is composed of, for example, a thin copper plate having a thickness of about 0.2 mm. Both electrode tabs 215A and 215B are provided with insertion holes 272A and 272B for inserting through bolts connecting the stacked electrodes. It should be noted that the peripheral portion 216 of the flat battery 214 that is heat-sealed and bonded is positioned and held by a holding portion formed on the frame. The stacking direction of the flat battery is the same as the stacking direction of the positive electrode plate and the negative electrode plate constituting the power generation element.

  4 and 5 are diagrams showing the arrangement state of the flat battery in the frame, and FIG. 6 is a diagram showing the laminated state of the frames.

  As shown in FIGS. 4 and 5, the frame 210 can arrange four flat batteries 214 </ b> A to 214 </ b> D in the longitudinal direction. In the frame 210, flat batteries 214A to 214D are arranged with their polarities alternately arranged. An insulating washer 212 or a conductive washer, which is an insulating member, is embedded in one end of the frame 210, and a peripheral edge supporting portion 218 that supports the peripheral edge portion 216 of each flat battery is formed in the frame 210. A central portion of the frame 210 surrounded by the peripheral edge support portion 218 in the frame 210 is opened, and as shown in FIG. 6, adjacent elements in the stacking direction (heat sinks 300 and 350, intermediate heat sinks 325A to 325C or frames to be stacked). The other 220 flat batteries 225A to 225D) and the outer surfaces of the flat batteries 214A to 214D can be in direct contact with each other. The other end of the frame 210 is provided with an opening 217A for ultrasonic welding the electrode tabs 215A or 215B of the flat batteries 214A to 214D to the electrode tabs of the flat batteries adjacent in the stacking direction. .

  As shown in FIG. 6, six frames, in which insulating washers are embedded and in which conductive washers are embedded, are alternately stacked. An intermediate heat sink 325C is laminated thereon, and further, six frames, an intermediate heat sink 325B, six frames, an intermediate heat sink 325A, and six frames are laminated thereon to form the battery unit 200. Finally, The fixing plates 400 and 450 and the bolts and nuts 475 are sandwiched between the heat sinks 300 and 350 from both ends in the stacking direction.

  The assembled battery 100 configured as described above includes four rows of battery stacks in which 24 flat batteries are stacked. As shown in FIG. 7, each of the battery stacks 250, 260, In 270 and 280, flat batteries are all connected in series in the stacking direction.

  That is, the connection between the flat batteries on the left side of the battery stack 250 is performed by ultrasonic welding, and the insulation between the flat batteries (the square mark in the figure) is performed with an insulating tape. It has been broken. On the other hand, the flat batteries on the right side of the battery stack 250 are connected to each other by a conduction washer (the circled portion in the figure), and the flat batteries are insulated from each other (the triangular mark in the drawing) by an insulating washer. . Therefore, when the assembled battery 100 is assembled, all the flat batteries constituting the battery stack 250 are connected in series. In the other battery stacks 260, 270, and 280, all flat batteries are connected in series with the same structure.

  The battery stacks 250, 260, 270, 280 are connected in series by bus bars 292, 294, 296 (provided on the heat sinks 300, 350). In this way, all flat batteries constituting the assembled battery 100 are connected in series. When such a connection method is adopted, the connection portions of the power terminals 490A and 490B can be made only in one direction (the upper side of the heat sink 300), so that power wiring after the assembled battery is easily installed and productivity is improved. .

  8-11 is a figure where it uses for description of the assembly process of the assembled battery concerning this Embodiment.

  In assembling the assembled battery 100, first, the flat battery 214 shown in FIG. 3 is arranged on the frames 210 and 220 as shown in FIGS. 4 and 5, and six frames on which the flat batteries are arranged are stacked. A battery unit 200 is formed by stacking a total of 24 frames with an intermediate heat sink interposed therebetween. Next, the battery unit 200 is sandwiched between the heat sinks 300 and 350 from both sides of the battery unit 200 in the stacking direction. As shown in FIGS. 8 and 9, tapered end surfaces 315 are formed on the respective end surfaces of the upper surface side of the heat sink 300 and the lower surface side of the heat sink 350 as shown in FIGS. 8 and 9.

  Then, the fixing plates 400 and 450 are disposed so as to be sandwiched from the opposite side surfaces of the battery unit 200, and bolts 475A to 475D are passed through the bolt through holes opened at the four corners of the fixing plates 400 and 450. Attach nuts 480A to 480D to the tip of ˜475D and tighten. As shown in FIGS. 8 and 9, the fixing plates 400 and 450 are provided with inclined surfaces 415 that are in contact with the entire two inclined surfaces 315 in the longitudinal direction of the heat sinks 300 and 350 (contact linearly). The provided columnar portions 410A, 410B, 460A, and 460B are formed. As shown in FIG. 9, the inclined surface start distance L1 between the columnar portion 410A and the columnar portion 410B of the fixed plate 400 is the inclined surface between the heat sink 300 and the heat sink 350 when the heat sinks 300 and 350 are stacked on the battery unit 200. It is larger than the end distance L2 and smaller than the inclined surface start distance L3. However, the dimensional relationship of L1 to L3 is such that the relationship of L3 <L1 <L2 is maintained even when the bolts 475A to 475D are completely tightened. The inclined surface is not limited to the linear contact with the entire inclined surface 315 as described above, and may be contacted with the inclined surface 315 in a dotted manner at a constant interval.

  When the nuts 480A to 480D are tightened in a state where the fixing plates 400 and 450 are connected by the bolts 475A to 475D, the fixing plates 400 and 450 are gradually biased toward each other, and accordingly, as shown in FIG. Thus, the columnar portion 410A moves in the left direction in the figure. Along with this movement, the inclined surface 415 of the columnar portion 410A comes into sliding contact with the inclined surface 315 of the heat sink 300, and pushes down the heat sink 300 in the downward direction in the figure. Conversely, the heat sink 350 is pushed up by the inclined surface 415 of the columnar portion 410B. The action of pushing down or pushing up the heat sinks 300 and 350 occurs similarly in the columnar portions 410B, 410C and 410D. Therefore, by tightening the nuts 480A to 480D, the heat sinks 300 and 350 are brought close to each other, and an appropriate pressure is applied to the battery unit 200 in the stacking direction.

  Note that the heat sinks 300 and 350 need not have inclined surfaces as shown in FIG. This is because even if the inclined surface is not formed, an appropriate pressure in the stacking direction can be applied to the battery unit 200 as in FIG.

  In the present embodiment, the heat sinks 300 and 350 are formed of aluminum plates having a plate thickness of 7.4 mm and a size of 294 mm × 586 mm, and a total of 160 kgf is applied to these using six bolts and nuts as in the past. It was verified how much the amount of displacement of the heat sink is different between the case where the load is applied and a total weight of 160 kgf is applied using the fixed plates 400 and 450 as in the present embodiment. In the conventional case, the difference between the maximum displacement amount and the minimum displacement amount in the longitudinal direction of the heat sinks 300 and 350 is 0.6 mm at the maximum. However, in the case of this embodiment, the difference was almost 0 mm. According to this verification result, according to the present embodiment, the strain distribution in the short direction of the heat sinks 300 and 350 can be made substantially constant, and a uniform pressure is applied to each flat battery constituting the battery unit 200. You can see that

  According to the assembled battery of the present invention, since the surface pressure of each flat battery becomes uniform, cycle (charge / discharge) characteristics as the assembled battery can be stabilized, and the reliability and life of the assembled battery are improved. .

  In order to reduce the number of parts, bolts 475A to 475D that function as connecting members may be formed integrally with the fixing plate 400 as shown in FIG. Furthermore, as shown in FIG. 13, the bolts 475A to 475D may be connected by a metal belt 500 so that the fixing plates 400 and 450 can be tightened simultaneously.

  The present invention can provide a uniform applied pressure to the flat battery constituting the assembled battery with a relatively simple structure, and thus can provide an assembled battery suitable as a battery mounted on a vehicle.

It is a perspective view of the assembled battery concerning this Embodiment. It is a side view of the assembled battery of FIG. It is an external view of the flat battery which comprises an assembled battery. It is a figure which shows the arrangement | positioning state to the flame | frame of a flat battery. It is a figure which shows the arrangement | positioning state to the flame | frame of a flat battery. It is a figure which shows the lamination | stacking state of a flame | frame. It is a figure which shows the connection state of the flat battery which comprises an assembled battery. It is a figure where it uses for description of the assembly process of the assembled battery concerning this Embodiment. It is a figure where it uses for description of the assembly process of the assembled battery concerning this Embodiment. It is a figure where it uses for description of the assembly process of the assembled battery concerning this Embodiment. It is a figure where it uses for description of the assembly process of the assembled battery concerning this Embodiment. It is a figure which shows the connection member of another form. It is a figure which shows the connection member of another form.

Explanation of symbols

100 battery packs,
200 battery unit,
210, 220 frames,
214, 214A-214D, 215A-215D flat battery,
215A, 215B electrode tab,
250, 260, 270, 280 battery stack,
300, 350 heat sink,
310A, 310B, 360A, 360B contact portion,
315 inclined surface,
325A, 325B, 325C Intermediate heat sink,
410A, 410B, 460A, 460B Columnar part,
400, 450 fixing plate,
475 bolt nut,
475A-475D bolts,
480A-480D nut,
490A, 490B power terminal,
500 Metal belt.

Claims (9)

A battery stack in which a plurality of flat batteries are stacked in the thickness direction;
A set of pressure plates in contact with the flat batteries located at both ends in the stacking direction of the battery stack;
A set of pressure-applying members for sandwiching the set of pressure plates from opposite sides of the battery stack;
A connecting member capable of connecting the set of pressure applying members and energizing the pressure applying members in a direction to bring them close to each other;
When the pressing member is brought close to each other by the connecting member, the pair of pressure plates move in a direction approaching each other, and the pressing force in the stacking direction can be applied to the battery stack. Has been
The pressure application member and the pressure plate are brought into contact with each other on at least one of the contact surfaces of the pressure application member and the pressure plate where the pressure application member and the pressure plate contact each other at a plurality of points. The assembled battery is characterized in that an inclined portion is formed for moving the pressure plates in directions close to each other . 2. The assembled battery according to claim 1, wherein the one set of pressure applying members are connected to each other by a connecting member extending substantially parallel to a side surface of the battery stack. The assembled battery according to claim 1 or 2, wherein the one set of pressure applying members is a quadrangular plate or a quadrangular frame. The assembled battery according to claim 3, wherein the one set of pressure applying members has a plurality of holes for weight reduction. The assembled battery according to claim 2, wherein the connecting member is formed integrally with one pressure applying member. The assembled battery according to claim 2 or 5, wherein the connecting member is formed of a bolt and a nut. The assembled battery according to claim 2, wherein the connecting member includes a spring member that is extendable in a longitudinal direction thereof. The assembled battery according to claim 1, wherein the one set of pressure plates is a heat sink that dissipates heat of the battery stack. The assembled battery according to claim 1, wherein the flat battery is a rectangular laminated battery.

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