JP5207283B2 - Battery pack and battery pack - Google Patents

Description

  The present invention relates to a battery pack and a battery pack, and more particularly to a battery pack and a battery pack in which laminated film exterior type cells such as a lithium ion battery and a lithium ion polymer battery are connected in series, in parallel, or a combination thereof.

  With the development and popularization of portable information devices such as mobile phones, notebook personal computers, and video cameras in recent years, the demand for secondary batteries that are small, lightweight, and have high energy density has greatly increased. Considering higher performance. As such a secondary battery, a lithium ion secondary battery is particularly attracting attention.

  A general structure of a lithium ion secondary battery is shown in, for example, Patent Document 1 and Patent Document 2, and a positive electrode active material composed of a positive electrode active material powder such as a lithium-cobalt composite oxide, a conductive powder, and a binder. A negative electrode active material layer made of a copper foil is formed on a negative electrode current collector surface made of a copper foil, a positive electrode formed by forming a layer on the surface of a positive electrode current collector made of aluminum foil, a carbon-based negative electrode active material powder, and a binder A negative electrode is stacked through a separator made of a porous film and impregnated with an electrolytic solution to form a power generation element.

  In order to reduce the size and weight, a lithium ion polymer battery in which the electrolyte is replaced with a polymer electrolyte is used, and a laminate film made of a metal foil such as aluminum and a polymer film is used as an exterior material for sealing a power generation element. It is used.

  FIG. 8 is a perspective view showing an example of a conventional unit cell using a laminate film as an exterior. In FIG. 8, a power generation element is sealed with a laminate film 1 to form a lithium ion battery, and a positive electrode tab 2 connected to the positive electrode of the power generation element and a negative electrode tab 3 connected to the negative electrode are respectively projected from the laminate film. Provided. At this time, the embossed shape provided on the laminate material in accordance with the battery capacity is provided only on the laminate film on one side, and the one-side embossed laminate unit battery provided on the laminate film on both sides, and the both-side embossed laminate cell provided on the laminate film on both sides Can be selected. FIG. 9 is a side view of a single-side embossed laminate cell, FIG. 10 is a side view of a double-side embossed laminate cell, 91 is an electrode tab, and 92 is an embossed laminate film.

  Next, an assembled battery in which a plurality of laminated lithium ion batteries are combined as a single battery will be described. As for the connection between the cells, in order to monitor the voltage of each cell, etc., a battery assembly that has been connected in series first is produced, and then the batteries are connected in parallel to produce a large-capacity battery assembly. In this case, resistance welding using a tab material is often performed. However, in the case of a lithium ion battery, since the materials of the positive electrode and the negative electrode are different because of the need to improve the characteristics, it is difficult to connect the different electrode tabs between the single cells, and the battery itself may dislike the heat, so voltage monitoring A relatively complicated process is also required for connecting the wire rods.

  For example, FIG. 11 is a perspective view showing a laminated connection structure using a single-side embossed laminated single battery having a relatively small capacity. First, an auxiliary tab 5 made of Ni having good weldability is welded to the positive electrode tab 4 made of Al, which is difficult to weld, by ultrasonic welding. Next, the inter-terminal connection tab 9 to which the voltage monitoring wire 6 is attached in advance by soldering or the like is connected between the negative electrode tab 7 of the first layer cell and the positive electrode tab 8 of the second layer battery. Each electrode tab is welded by resistance welding. If this is the case, it becomes an obstacle to stack the third and subsequent unit cells, so that the connected electrode tab member is folded back to a position where it does not interfere with the electrode rod for resistance welding. Thereafter, the same operation is repeated to stack the cells.

  FIG. 12 is a perspective view showing a laminated connection structure using a double-sided embossed laminate single battery having a relatively large capacity. In this case, since the distance between the centers of the upper and lower unit cells can be secured to some extent, it is possible to invert and connect the positive electrode tab 10 and the negative electrode tab 11 of the layers adjacent to each other vertically. is there. However, in this case as well, the voltage monitoring wire 6 dislikes the heat of the battery, so it is necessary to weld the one attached to another voltage monitoring wire attachment tab 13 at the same time when the electrode is connected. Similar to the type of battery, the auxiliary tab 12 made of Ni material must be welded first.

  As another conventional technique, the electrode tabs are sandwiched between metal blocks due to the difficulty of welding dissimilar metals as described above, or the stacked electrode tabs are sandwiched between insulating sheets and tightened with bolts and nuts, etc. There is also an example in which an assembled battery is configured. For example, Patent Document 3, Patent Document 4 or Patent Document 5 discloses such a connection structure.

Japanese Patent No. 3283213 JP 2005-129234 A Japanese Patent Laid-Open No. 2004-22395 JP 2004-273351 A JP 2004-6141 A

  Among the above prior arts, the connection structures shown in FIGS. 11 and 12 are not only required to be welded using an auxiliary tab made of Ni material, but also need to reduce the thermal load of the battery itself. There was a problem that man-hours for the process became long.

  Moreover, in the prior arts of Patent Document 3, Patent Document 4 or Patent Document 5, a method of sandwiching an electrode tab with a metal block or tightening with a bolt / nut is used, but a large space is required at the connection portion. In addition, since the weight is increased, the characteristics of the lithium ion battery, which is small and light, may not be utilized.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an assembled battery and a battery pack that facilitate connection between electrode tabs of unit cells while keeping the volume and weight small.

  In order to solve the above problems, a battery pack according to the present invention is an electrode tab formed by sealing a power generating element having a positive electrode, a negative electrode, and an electrolyte with a laminate film made of a metal foil and a resin film, and connected to the positive electrode or the negative electrode It has a structure that can be easily connected with widely used terminals by making the positive and negative electrode tab shapes of the cells having a so-called fast-on terminal tab side shape. It is said.

  In addition, in the case of a double-sided embossed laminated lithium battery, the positive and negative terminals should be used by overlapping with the different electrode tabs of the cells adjacent to the upper and lower layers, and the total thickness after the stacking is the normal standard. It is desirable that the thickness of the electrode tab is set to a half of the standard value of the faston tab terminal so as to be equal to the thickness of the faston tab terminal. In particular, it is most effective to adjust to 0.25 mm which is half of the thickness of 0.5 mm of the so-called 187 system faston tab terminal.

  In both cases where the battery pack is composed of single-side embossed laminate cells or double-sided embossed laminate cells, the final positive and negative output terminal portions do not overlap with the different polarities of adjacent layers. The connection is made by using an auxiliary tab for thickness conversion which is set to the same thickness as the negative electrode tab and 1/2 the thickness of the faston tab terminal. The auxiliary tab for thickness conversion may be formed with a bent projection for positioning and prevention of displacement.

  As described above, in the present invention, the positive and negative electrode tabs of the laminated unit cell are formed into the shape of a faston tab terminal whose thickness is ½ of the standard value, so that welding work is not required, and the unit cell is small and lightweight. Thus, an assembled battery can be configured without impairing such characteristics.

  That is, according to the present invention, it is possible to provide an assembled battery and a battery pack that facilitate connection between the electrode tabs of the unit cells while keeping the volume and weight small.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 4 is a perspective view of a single-side embossed laminate cell having electrode tabs according to the present invention, and FIG. 5 is a perspective view of a double-sided embossed laminate cell having electrode tabs according to the present invention. In FIG. 5, although hidden behind, the lower laminate film is also embossed.

  The cell used in the present invention is a lithium ion battery in which a power generation element having a positive electrode, a negative electrode, and an electrolyte is sealed with a laminate film made of a metal foil and a resin, similarly to the conventional single cell shown in FIG. The electrode tabs of the positive electrode tabs 15 and 16 and the negative electrode tabs 17 and 18 are each formed in the shape of a faston tab terminal whose thickness is ½ of the standard value.

  By the way, the material of the positive electrode tab is most suitable for Al, and the material of the negative electrode tab is most suitable for Cu.

  FIG. 1 is a perspective view showing a laminated connection structure using a single-side embossed laminate cell according to the present invention. Attaching the auxiliary tabs 30 for thickness conversion to the tips of the positive electrode tab 15 and the negative electrode tab 17 to be connected, and attaching them to both ends of the connection line 20 with the total thickness being the same as that of a normal faston tab terminal The connection is made by press-fitting a commercially available faston terminal receptacle 19 into each different pole. The auxiliary tab 30 for thickness conversion is shown in a perspective view in FIG. The auxiliary tab 30 is formed with a bent projection 34 for positioning and preventing displacement. As an example, the press-fitting portion of the auxiliary tab 30 may be formed to have a width of 4.75 mm, a length of 6.35 mm, and a thickness of 0.25 mm in accordance with a 187 system faston terminal. After this connection work is completed, the same work is repeated according to the number of stacked sheets.

  FIG. 6 is a perspective view showing a laminated connection structure using unit cells to which a voltage monitoring wire according to the present invention is added. It is also possible to attach the voltage monitoring wire 23 together on one side of the inter-terminal connection line as shown in FIG.

  FIG. 7 is a perspective view showing a structure for connecting the external connection line to the electrode tab with the auxiliary tab 30 for thickness conversion according to the present invention interposed therebetween. Thus, the final output positive electrode or negative electrode can be connected by press-fitting the faston terminal receptacle 19 to which the output line 22 is attached in a state where the auxiliary tabs 30 for thickness conversion are stacked. Become.

  FIG. 3 is a perspective view showing a laminated connection structure using a double-sided embossed laminate cell according to the present invention. In the case of the embossed shape on both sides, it is possible to secure an insulation distance between the different-polarity terminals that are not connected, so that it is possible to directly connect the upper and lower different polarities by alternately switching the front and back of the unit cells. Supplementally, in the case of one-side embossed shape, when the embossed side is opposite, the insulation distance between the different-polarity tabs that are not connected can be secured, but when the flat side is opposite, the insulation distance between the different-polarity tabs that are not connected is secured. I can't. On the other hand, in the case of the embossed shape on both sides, such an insulation distance cannot be secured. Therefore, even if an auxiliary tab as in embossing on one side is not used, it can be made equal to the thickness of a normal faston terminal by simply overlapping the cell electrode tabs. In this state, the faston terminal receptacle 21 is press-fitted and connected in the same manner as described above. At this time, it is also possible to previously connect the voltage monitoring wire 23 (FIG. 6) to the faston terminal receptacle as in FIG.

  Further, even in the case of an assembled battery made up of single-sided embossed cells, in the case of the final output terminal, connection is made using the auxiliary tab 30 for thickness conversion, as in FIG.

  Further, the battery pack of the present invention is obtained by housing the assembled battery produced as described above together with a protective circuit including a voltage monitoring circuit in an outer case made of resin or a composite material thereof.

  As described above, according to the present invention, a wide range of commercially available faston terminals can be used for connection between unit cell tabs, and a unit cell without compromising the lithium ion characteristics of small size and light weight with relatively low cost and manufacturing steps. It is possible to obtain a structure for connecting between the two.

  By the way, when the capacity of the unit cell is less than 1 Ah, both the unit cell volume and weight are small, and the battery pack is often configured in the unit cell state rather than as an assembled battery. The structure is suitable for connection between single cells having a battery capacity of 1 Ah or more. Further, the maximum capacity of the unit cell having the electrode tab suitable for the connection structure according to the present invention is assumed to be about 18 Ah.

The perspective view which shows the lamination | stacking connection structure using the one side embossing type | mold lamination cell concerning this invention. The perspective view of the auxiliary tab for thickness conversion concerning the present invention. The perspective view which shows the lamination | stacking connection structure using the both-sides embossing type | mold lamination cell which concerns on this invention. The perspective view of the one-side embossing type | mold lamination cell which has the electrode tab which concerns on this invention. The perspective view of the both-sides embossing type | mold lamination cell which has the electrode tab which concerns on this invention. The perspective view which shows the laminated connection structure using the cell which added the wire for voltage monitoring which concerns on this invention. The perspective view which shows the structure which connects an external connection line to an electrode tab on both sides of the auxiliary tab for thickness conversion which concerns on this invention. The perspective view which shows an example of the conventional cell. The side view of a one-side embossing type | mold lamination cell. The side view of a both-sides embossing type | mold lamination cell. The perspective view which shows the lamination | stacking connection structure using the conventional one side embossing type | mold lamination cell. The perspective view which shows the lamination | stacking connection structure using the conventional both-sides embossing type | mold lamination cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laminate film 2, 4, 8, 10, 15, 16 Positive electrode tabs 3, 7, 11, 17, 18 Negative electrode tabs 5, 12, 30 Auxiliary tabs 6, 23 Voltage monitoring wire 9 Terminal connection tab 13 Voltage monitoring wire Mounting tabs 19 and 21 Faston terminal receptacle 20 Connection line 22 Output line 34 Bending protrusion 91 Electrode tab 92 Embossed laminate film

Claims (5)

A power generation element having a positive electrode, a negative electrode, and an electrolyte is sealed with a laminate film made of a metal foil and a resin film, and a unit cell is formed with a configuration of a secondary battery in which an electrode tab is connected to the positive electrode and the negative electrode. In an assembled battery in which a plurality of unit cells are stacked and connected to each other in series or parallel or a combination thereof,
The tip of the electrode tab of the unit cell is formed in the tab shape of a Faston terminal,
A battery pack characterized in that a faston terminal receptacle is press-fitted into the tip portion, and electrical connection is made between cells or externally.   The assembled battery according to claim 1, wherein a faston terminal receptacle is press-fitted after an auxiliary tab having the same thickness as that of the electrode tab is attached to the tip of the electrode tab.   The assembled battery according to claim 1, wherein the faston terminal receptacle is press-fitted after the tip portions of the electrode tabs having different polarities are overlapped between the cells adjacent in the stacking direction.   The assembled battery according to any one of claims 1 to 3, wherein a battery capacity of the unit cell is 1 Ah or more.   A battery pack comprising the battery pack and the voltage monitoring circuit according to claim 1 in an outer case.

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