JP2004152706A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack capable of quickly adapting to a change in the number of unit cells used and with which an assembly work can be safely and efficiently carried out. <P>SOLUTION: The battery pack 1 has a connection structure of four in series of two unit cells 2 arrayed in parallel, namely, eight unit cells 2 arrayed in a row. A width of a plate 3 is smaller than an outer diameter of the unit cell 2, and the plate 3 is provided with openings 13 at portions in correspondence with outer terminals of the unit cells 2, and a plate-like metal bus bar for connecting the unit cells is insertion-molded so as to choke up the openings 13. The metal bus bar has a through-hole for welding formed at a connection part with the outer terminal of the unit cell 2. Safety is secured since the plate 3 does not stick out of an outer periphery the battery pack 1, and the outer terminal of the unit cell 2 and the metal bus bar can be connected with spot welding through the through-hole. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an assembled battery, and more particularly, to an assembled battery in which a plurality of columnar cells are mechanically and electrically connected to each other and plates having electrical insulating resin are disposed on both sides having polarity.
[0002]
[Prior art]
Conventionally, in an assembled battery in which a plurality of unit cells are combined, the unit cells are connected in series and / or in parallel in the assembled battery. For example, in an assembled battery in which three columnar cells are adjacent and arranged side by side upside down, the terminals of the cells are connected in series by a plate-shaped metal connection bus bar, and both ends of the assembled battery have external output. The terminals are connected, and the entire battery pack is held by an outer case made of an electrically insulating resin, or is covered with a heat-shrinkable shrink tube or the like to ensure electrical insulation.
[0003]
When covering the entire battery pack with a heat-shrinkable shrink tube, simply covering the battery pack with a heat-shrinkable shrink tube can easily break the tube during heat shrinkage due to the sharp edges and protruding parts protruding from the battery pack before coating. The edge portion is hidden by paper or the like (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP 2001-057192 A (FIG. 1, paragraph number “0031”)
[0005]
[Problems to be solved by the invention]
However, for example, when a lithium battery, which is a high-performance secondary battery, is used as a unit cell, if the above-described electric insulating paper is simply placed on the assembled battery, each lithium battery will have all the voltages for charge / discharge management. Since the measurement is required, the wiring work becomes complicated, and there is a problem that the work is dangerous and the efficiency is low when all the bus bars connecting the cells are completely exposed. In addition, when there is a change in the number of cells used or the series-parallel connection, it takes time to newly manufacture or change a mold or the like, and it has been difficult to quickly respond to customer needs.
[0006]
In view of the above proposal, an object of the present invention is to provide an assembled battery that can quickly respond to a change in the number of cells used and that can perform assembly work safely and efficiently.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a battery assembly in which a plurality of columnar cells are mechanically and electrically connected, and a plate made of an electrically insulating resin is disposed on both sides having polarity, the plate comprising: The width is smaller than the outer diameter of the unit cell, an opening is provided at a position corresponding to the external terminal of the unit cell, and a metal bus bar for mechanically and electrically connecting the unit cell is fixed so as to close the opening. A through hole for welding is formed in the metal bus bar at a location where the metal bus bar is connected to an external terminal of the unit cell.
[0008]
In the present invention, since the width of the plate is smaller than the outer diameter of the unit cell, the plate does not protrude from the outer periphery of the assembled battery even when visually arranged, so that safety can be ensured (for example, the assembled battery is thermally shrunk). If the plate protrudes from the outer periphery of the battery pack when covering with the shrink tube, the edge will come out, leading to breakage of the heat shrink shrink tube and exposing the connection part.) It has an opening and can be fixed to the plate by arranging a metal bus bar that mechanically and electrically connects the cells so as to close this opening, and the metal bus bar has a penetration for welding. Since the holes are formed, the cells can be connected by welding the external terminals of the cells and the metal bus bars through the through holes.
[0009]
In the present invention, if a plate-shaped metal bus bar is integrally formed on the plate, an assembling jig and an assembling man-hour when fixing the metal bus bar to the plate become unnecessary, and the workability is improved, and the surface of the metal bus bar is formed by the opening. By connecting to the external terminal of the unit cell in a state depressed from the surface of the unit cell, the displacement of the unit cell can be corrected and the shock applied to the unit cell can be absorbed by the leaf spring function of the metal bus bar. Further, if the metal bus bar has a projection at the center for connecting to the lead wire, the projection can be located at a position with a small potential drop when connecting the parallel unit cells in series. By connecting the lead wire and the projection in advance as a pre-process, the assembling work can be performed without worrying about an electrical short circuit or the like, so that workability and safety can be improved.
[0010]
In addition, if the shape of the metal bus bar at the output end of the assembled battery is T-shaped, two cells can be connected to the metal bus bar at the output end of the assembled battery. If the legs that extend toward the valley space are bent almost vertically, the valley space between the cells, which is a dead space, can be effectively used as a connection space for electrical output, and volume efficiency can be increased. it can. In addition, if the plate has a positioning protrusion along the side peripheral surface of the unit cell in the valley space between the unit cells, when arranging the unit cells, they are positioned in units of the unit cell and move with respect to each other. Since the movement of each unit cell is regulated as a whole assembled battery by checking each other, a jig at the time of assembling becomes unnecessary, which is advantageous in terms of workability and cost.
[0011]
Furthermore, if the battery pack is covered with the heat-shrinkable shrink tube and an opening for leading out the lead wire is formed in the heat-shrinkable shrink tube, the cells are electrically and mechanically connected with the metal bus bar. However, since the fixation of each cell is insufficient in terms of vibration resistance, covering the entire assembled battery with a heat shrinkable shrink tube increases insulation, and can improve workability such as carrying, The lead wire can be led out from the opening of the heat-shrinkable shrink tube. Further, if the cells are arranged in a line, and the cells and the plate are covered with a single heat-shrinkable shrink tube, the electric exposed portion of the assembled battery in which the columnar cells are arranged in a line. By arranging the cells in a line, even if there is a change in the number of batteries used or in the series-parallel connection structure, quick response can be achieved. Before welding the external terminals of the unit cell, it is difficult to limit the position of the unit cell in the longitudinal direction of the battery pack by using only the plate, which also hinders the movement of the work. If the battery pack is held along the outer circumference of the battery pack in a direction perpendicular to the shrinking direction of the shrink tube with a fixing tape, there is no looseness of the battery cells in the longitudinal direction at the stage before welding, and the cell position varies in the movement of the work. , The work efficiency can be improved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an assembled battery to which the present invention can be applied will be described with reference to the drawings.
[0013]
(Constitution)
As shown in FIG. 1, the battery pack 1 of the present embodiment is entirely covered with a heat-shrinkable shrink tube 15, and has openings 16 formed on both sides in the longitudinal direction. FIG. 2 shows the assembled battery 1 before being covered with the heat-shrinkable shrink tube 15. As shown in FIG. 2, the battery pack 1 includes eight columnar cells 2. The unit cell 2 is a high-performance lithium secondary battery using lithium manganate or the like as a main constituent material of a positive electrode mixture and amorphous carbon or the like as a main constituent material of a negative electrode mixture, and has a cylindrical shape with high heat conductivity. It is covered with a casing. The assembled battery 1 has an electric connection structure in which two unit cells 2 are connected in parallel and four sets of unit cells 2 connected in parallel are connected in series. Such a connection is performed via plates 3 made of an electrically insulating resin and having a length in the width direction smaller than the outer diameter of the unit cells 2 and arranged on both sides of the eight unit cells 2.
[0014]
As shown in FIGS. 2 and 3, the plate 3 has an opening 13 at a position corresponding to an external terminal of the unit cell 2. A plate-shaped metal bus bar is buried by insert molding so as to close the opening 13. As shown in FIG. 4, there are two types of metal bus bars, a T-shaped metal bus bar 4 and an I-shaped metal bus bar 5, and two I-shaped metal bus bars 5 are embedded in one plate 3. (See FIG. 4A). In the other plate 3, one I-shaped metal bus bar 5 and two T-shaped metal bus bars 4 are embedded (see FIG. 4B).
[0015]
In the opening 13 formed in the plate 3, the surface of the metal bus bar (T-shaped metal bus bar 4 and I-shaped metal bus bar 5) is depressed with respect to the surface of the plate 3. A step 8 is formed at the periphery of the opening 13. Further, a cross-shaped welding through hole (projection) is formed in the metal bus bar at a position substantially at the center of the opening 13 serving as a connection point of the plate 3 with the external terminal of the unit cell 2. Furthermore, the metal bus bar has a metal projection 6 projecting upward from a valley-shaped space 9 (dead space) between the unit cells 2 at the center in the longitudinal direction. Although the tip of the metal projection 6 is exposed from the upper end surface of the plate 3, the exposed length is limited to the height of the outer diameter of the cell 2 or less so as not to be an edge with respect to the heat-shrinkable shrink tube 15. I have.
[0016]
As shown in FIGS. 4B and 5, the T-shaped metal bus bars 4 are buried at both ends of the other plate 3, and are located below the valley-shaped space 9 from the center in the longitudinal direction (the metal projections 6). The T-leg extending toward (opposite direction) has a bent portion 10 bent substantially vertically. A tab having a shape of 250 series is formed at the tip of the bent portion 10. On the upper end surface and the lower end surface of the plate 3, positioning protrusions 11 having a shape along the side peripheral surface of the unit cell 2 are integrally formed at positions corresponding to the valley spaces 9. The positioning protrusion 11 has a symmetrical shape when viewed from the center of the protrusion. The T-shaped leg of the T-shaped metal bus bar 4 is bent substantially vertically below the positioning protrusion 11 formed on the lower end surface of the plate 3.
[0017]
As shown in FIGS. 2 and 5, a voltage detection line 7 for detecting the voltage of the cell 2 is connected to the metal protrusion 6, and the other end of the voltage detection line 7 is connected to a connector. In addition, a lead wire from a temperature sensor such as a thermistor is also connected to the connector. The external terminal of each cell 2 is spot-welded to the metal bus bar via a welding through hole formed in the metal bus bar. Further, an output lead wire 14 for taking out the output of the battery pack 1 is connected to the tip of the bent portion 10 on which the 250 series tab is formed.
[0018]
As shown in FIG. 2, the center of each unit cell 2 is wound around the outer periphery of the battery pack with a fixing tape 12. As shown in FIG. 1, a voltage detection wire 7 and an output lead wire 14 are led out of one opening 16 of the heat-shrinkable shrink tube 15, and an output lead wire 14 is led out of the other opening 16. When the battery pack 1 is used as a single unit, the output leads 14 are connected to a load. When the battery pack 1 is connected in series and parallel and used as a battery module, the output leads 14 are connected in series and parallel. Connected and connected to the load. The connector on which the voltage detection lines 7 are connected is connected to a cell controller (a device that controls the assembled battery 1), which is not shown.
[0019]
(Preparation of assembled battery)
Next, a procedure for manufacturing the battery pack 1 of the present embodiment will be described.
[0020]
As shown in FIG. 5, the voltage detection line 7 is integrated with the plate 3 by connecting one end to the metal protrusion 6 and the other end to the connector in a process before assembling the plate 3 to the unit cell 2. An output lead wire 14 is connected to the tip of the bent portion 10.
[0021]
In the previous step, the plate 3 with the wiring in which the voltage detection line 7 and the output lead 14 are integrated is prepared, and the unit cells 2 are arranged along the positioning protrusions 11 formed on the plate 3, and the other wiring is provided. After arranging the attached plate 3 so that the drawing direction of the voltage detection line 7 is the same, the fixing tape 12 is wound around the outer periphery of the battery pack 1 as shown in FIG. The single cells 2 are mechanically and electrically connected by spot welding through the formed welding through holes.
[0022]
As shown in FIG. 1, a single cylindrical heat-shrinkable shrink tube 15 is heat-shrinked in a state where the voltage detection wire 7 and the output lead wire 14 are pulled out from the opening 16, thereby forming the plate 3 and the cell 2. Is assembled, and the assembled battery 1 is entirely coated. The above-described fixing tape 12 is wound along the outer periphery of the battery pack 1 in a direction perpendicular to the direction in which the heat-shrinkable shrink tube 15 contracts.
[0023]
(Action, etc.)
Next, the operation and the like of the battery pack 1 of the present embodiment will be described.
[0024]
The assembled battery 1 according to the present embodiment is configured such that eight unit cells 2 are arranged in parallel with each other so as to be four in series, and are electrically connected by an electrically conductive metal bus bar. 3, the plate 3 is smaller than the outer diameter of the unit cell 2, so that the risk of protruding from the outer periphery of the assembled battery 1 can be reduced even when the plate 3 is visually arranged. That is, when the plate 3 protrudes from the outer periphery of the battery pack 1, the edge is formed, which leads to breakage of the heat-shrinkable shrink tube 15 and lowers safety. However, in the battery pack 1, the unit cells 2 are arranged in a line. By covering the plate 3 and the unit cell 2 with a single heat-shrinkable shrink tube 15 that covers the entire assembled battery 1, it is possible to eliminate the electric exposure part and to ensure safety. Further, in the battery pack 1, the cells 2 are arranged in a line to reduce the number of component parts of the battery pack 1 (substantially eight cells 2 and two wiring plates 3). Even if there is a change in the number or series / parallel connection structure, quick response can be achieved.
[0025]
In addition, when performing connection work of the voltage detection wire 7 and the output lead wire 14, if connection of wiring is performed by solder or the like in a state where the battery pack 1 is not insulated, solder dripping or contact of an iron tip may occur. Although there is a possibility that a short circuit may occur between the cells 2, the connection operation is performed in the assembled battery 1 in a process before assembling the cells 2 to the plate 3 as shown in FIG. Work efficiency is improved.
[0026]
Furthermore, in the assembled battery 1, since the metal bus bar is integrally formed on the plate 3, no assembly jig or the like is required when disposing the metal bus bar on the assembled battery 1, and the number of parts and man-hours are reduced, and workability is reduced. Is improved. In addition, since the surface of the metal bus bar is recessed at the step 13 from the surface of the plate 3 at the opening 13 and connected to the external terminal of the cell 2, the displacement of the cell 2 is corrected, and the external shock applied to the cell 2 is corrected. Can be absorbed by the leaf spring function of the metal bus bar. In addition, the connection work can be easily performed by spot welding with the external terminal of the unit cell 2 through the welding through hole substantially at the center of the opening 13 of the metal bus bar.
[0027]
In the assembled battery 1, a positioning projection 11 is provided on a surface of the plate 3 that contacts the single cell 2 along a valley space 9 existing between the single cells 2. For this reason, when arranging the cells 2, the cells 2 are positioned in units of the cells 2, and the movement of the cells 2 is regulated as a whole of the assembled battery 1 by the movement of the cells 2. Is done. Therefore, no jig is required at the time of assembly, and work efficiency and cost efficiency can be improved.
[0028]
Further, in the assembled battery 1, the cells 2 are electrically and mechanically connected by a metal bus bar, but each of the cells 2 is insufficiently fixed in terms of vibration resistance, and the entire assembled battery 1 is integrally formed. There is a need to. For this reason, the entire battery pack 1 is covered with the heat-shrinkable shrink tube 15 to enhance the insulation, and the whole is integrated to improve workability such as carrying. In addition, an opening 16 for drawing out the voltage detection line 7 and the like of each cell 2 is formed on the short side surface by heat-shrinking the cylindrical heat-shrinkable shrink tube 15, and a dead space between the plate 3 and the cell 2 is formed. The space efficiency is enhanced in combination with the effective use of the valley-shaped space 9 in which the pits occur.
[0029]
In the assembled battery 1, the single cells 2 are arranged in a line, but the two single cells 2 have a shape having the same electrical polarity and are basically considered to be four single cells 2. And the polarity of the cell 2 is different at the center of the metal bus bar. In view of the potential drop, the metal protrusion 6 is projected to the portion where the drop is the least, so that the voltage of the cell 2 is accurately detected. be able to. Also, in the battery pack 1, four cells 2 are used as a reference, so that two cells 2 are not connected at the ends. Therefore, in order to make the two unit cells 2 have the electric output of the assembled battery 1, the shape of the metal bus bar is T-shaped. Further, the legs extending vertically from the portion connecting the cells 2 extend to the valley-shaped space 9 between the cells 2 and are bent at a right angle. The dead space of the shape space 9 is used as a connection space for electric output, thereby improving the volumetric efficiency.
[0030]
Furthermore, although the structural strength of the assembled battery 1 to which the metal bus bar is welded is as described above, it is difficult to limit the position of the unit cells 2 in the longitudinal direction of the assembled battery 1 only by the plate 3 before welding, This also hinders the movement of the work. In the assembled battery 1, in the stage before welding, the fixing tape 12 is wound around the center of the side peripheral surface of the unit cell 2 along the outer periphery of the assembled cell 1, thereby preventing the floating of the unit cell 2 in the longitudinal direction, and Variations in the position of the unit cells 2 during movement are reduced, and assembling workability is improved.
[0031]
In the battery pack 1, the voltage detection line 7 is drawn from one side of the battery pack 1. For this reason, the connection distance to the cell controller is shortened, and routing of the voltage detection lines 7 is facilitated.
[0032]
In the present embodiment, an example in which the metal bus bar is integrally formed with the plate 3 has been described. However, the present invention is not limited to this, and the metal bus bar is provided in the opening 13 of the plate 3 so that the plate 3 can be formed. May be fixed. Further, a fixing projection for securing the metal bus bar may be formed on the plate 3.
[0033]
Further, in the present embodiment, the bent portion 10 in which the T-shaped leg portion extending downward from the center in the longitudinal direction of the T-shaped metal bus bar 4 to the lower side of the valley-shaped space 9 is bent substantially vertically is illustrated. If a part of the bent portion is cut and constricted, the battery pack 1 is thermally cut off when an excessive current flows in or out due to an external short circuit or the like, so that the T-shaped metal bus bar 4 functions as a fuse. Can be done.
[0034]
Further, in the present embodiment, an example in which the connection structure of the assembled battery 1 is such that two unit cells 2 are arranged in parallel and four unit cells 2 are arranged in series, but the present invention is not limited to this. The present invention is also applicable to a case where all the eight single cells 2 are connected in series, and it goes without saying that the present invention can be applied even if the number of the single cells 2 is increased or decreased.
[0035]
【The invention's effect】
As described above, according to the present invention, since the width of the plate is smaller than the outer diameter of the unit cell, the plate does not protrude from the outer periphery of the assembled battery even when visually arranged, so that safety can be secured. The plate has an opening at a position corresponding to the external terminal of the unit cell, and a metal bus bar for mechanically and electrically connecting the unit cell is arranged so as to close this opening, thereby fixing the unit to the plate. Since the metal bus bar is formed with a through hole for welding, the external terminal of the unit cell and the metal bus bar can be welded through the through hole to connect the unit cell. Can be obtained.
[Brief description of the drawings]
FIG. 1 is an external perspective view of an assembled battery according to an embodiment to which the present invention can be applied.
FIG. 2 is an external perspective view of a battery pack before covering a heat-shrinkable shrink tube.
FIG. 3 is an external perspective view showing the assembled battery in a state where the unit cells are arranged on a plate.
4A and 4B are side views of the plate, wherein FIG. 4A shows a state viewed from the direction of arrow A in FIG. 2, and FIG. 4B shows a state viewed from the direction of arrow B in FIG.
FIG. 5 is an external perspective view showing the relationship between the provided plate and the unit cells.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 battery pack 2 unit cell 3 plate 4 T-shaped metal bus bar 5 I-shaped metal bus bar 6 metal protrusion (protrusion)
7 Voltage detection line (lead wire, part of lead wire)
9 valley-shaped space 11 positioning protrusion 12 fixing tape 13 opening 14 output lead wire (part of lead wire)
15 Shrink shrink tube 16 Opening

Claims (8)

In a battery pack in which a plurality of columnar cells are mechanically and electrically connected and a plate made of an electrically insulating resin is disposed on both sides having polarity, the plate has a width smaller than the outer diameter of the cell, An opening is provided at a position corresponding to the external terminal of the unit cell, and a metal bus bar for mechanically and electrically connecting the unit cell is fixed so as to close the opening, and the unit cell is attached to the metal bus bar. Characterized in that a through hole for welding is formed at a connection point with the external terminal of (1). The plate is formed integrally with the plate-shaped metal busbar, and the surface of the metal busbar is connected to an external terminal of the unit cell in a state in which the surface of the metal busbar is recessed from the surface of the plate. The battery pack according to claim 1, wherein: 3. The battery pack according to claim 2, wherein the metal bus bar has a projection at a center thereof for connecting to a lead wire. The metal bus bar at the output end of the battery pack among the metal bus bars has a T-shape, and legs extending toward a valley-shaped space between the unit cells are bent substantially vertically. The assembled battery according to claim 2 or 3, wherein The assembled battery according to any one of claims 1 to 4, wherein the plate has a positioning projection along a side peripheral surface of the unit cell in a valley space between the unit cells. 6. The battery pack according to claim 1, wherein the battery pack is further covered with a heat-shrinkable shrink tube, and the heat-shrinkable shrink tube has an opening for leading a lead wire. Item 2. The battery pack according to item 1. The battery pack according to claim 6, wherein the cells are arranged in a line, and the cells and the plate are covered with a single heat-shrinkable shrink tube. The assembled battery according to claim 6, wherein the unit cell is held by a fixing tape along an outer periphery of the assembled battery in a direction orthogonal to a shrinking direction of the heat-shrinkable shrink tube. 9. .

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