JP3996525B2 - Assembled battery, assembled battery manufacturing method, and laminated battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembled battery, a method for manufacturing the assembled battery, and a laminated battery.
[0002]
[Prior art]
Conventionally, when a battery is used as a power source, electrode terminals (tabs) are connected in series to obtain a required voltage from the rated voltage of a single cell (cell), or electrode terminals are arranged in parallel to obtain a required current capacity. It has been commercialized as an assembled battery (pack) connected to.
[0003]
On the other hand, batteries used in portable information communication devices such as mobile phones and laptop computers, and small electronic devices such as video cameras and card-type calculators that emphasize portability are increasingly lighter and thinner. It has been demanded. In addition, with increasing demands for resource saving and energy saving for international environmental protection, electric vehicles and hybrid electric vehicles (hereinafter simply referred to as “electric vehicles etc.”) equipped with a battery for driving a motor. ) Is being developed rapidly. Of course, batteries mounted on electric vehicles and the like are also required to be light and thin in order to improve steering characteristics and cruising distance.
[0004]
In order to make the battery lighter and thinner in response to such a request, a laminate material in which a metal layer such as aluminum and a heat-weldable resin layer are laminated on the exterior body through an adhesive layer to form a thin sheet. Has been developed (see, for example, Patent Document 1). In general, a laminate material has a structure in which both surfaces of a thin metal layer such as aluminum are covered with a thin resin layer, and is resistant to acids and alkalis, and is lightweight and flexible.
[0005]
FIG. 3 shows an example of a flat battery having a conventional laminate material as an outer package.
[0006]
In an outer package 101 made of a laminate material, an electrode group 102 in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween and an electrolytic solution are hermetically stored. A positive electrode terminal 103 connected to the positive electrode extends from one side of the outer package 101, and a negative electrode connected to the negative electrode from the side opposite to the side where the positive electrode tab 103 extends. A terminal 104 extends. Aluminum is often used as the positive electrode terminal 103, and copper is frequently used as the negative electrode terminal 104 due to its electrical characteristics and low cost.
[0007]
When such laminate-type batteries 106 are connected in series, a copper foil 105 is added to the positive electrode terminal 103 made of aluminum as shown in FIG. 4 in order to avoid corrosion due to contact with different metals.
[0008]
FIG. 5 schematically shows series connection and parallel connection in an example of a conventional laminated battery.
[0009]
FIG. 5A schematically shows a laminated battery 106 in which one end of a copper foil 105 is joined to a positive electrode terminal 103 made of aluminum by welding a. When the laminate type battery 106 shown in FIG. 5A is connected in series, as shown in FIG. 5B, the other end of the copper foil 105 is connected to the copper negative electrode terminal of the other laminate type battery 106. 104 is joined by welding a ′.
[0010]
On the other hand, in the case of parallel connection, as shown in FIG. 5 (c), the copper foil 105 is added to the positive electrode terminal 103 by welding a and at the same time the positive electrode terminals 103 of the laminate type battery 106 are welded to each other by welding b. Join. The negative electrode terminals 104 are also welded in the same manner.
[0011]
Furthermore, in order to serially connect the battery packs connected in parallel, as shown in FIG. 5D, the other end of the copper foil 105 of the battery pack connected in parallel is connected to another battery pack connected in parallel. To the negative electrode terminal 104 made of copper by welding a ′.
[0012]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-203524
[Problems to be solved by the invention]
However, in the conventional joining method described above, in the serial connection, as shown in FIG. 5B, two welds a and a ′ are required for the connection between the terminals. Further, in the parallel connection, as shown in FIG. 5 (c), the weld a for series connection and the weld b for parallel connection are in the same place, and therefore, the concentration of thermal stress and the associated mechanical stress. There is concern about a decrease in strength. Furthermore, as shown in FIG. 5D, when two laminated batteries 106 connected in parallel are further connected in series, as many as four weldings are required between d.
[0014]
As described above, in the conventional joining method described above, the number of welded portions in the electrode terminal tends to increase, which may cause problems such as an increase in cost, a decrease in reliability, and an increase in electrical resistance in the electrode. there were.
[0015]
Accordingly, an object of the present invention is to provide an assembled battery, an assembled battery manufacturing method, and a laminated battery that have a small number of junctions in an electrode, are highly reliable, and are inexpensive.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, an assembled battery of the present invention includes a laminated electrode formed by laminating a first polarity electrode plate and a second polarity electrode plate, and a first polarity electrode plate. A first electrode terminal electrically connected; and a second electrode terminal electrically connected to the electrode plate having the second polarity, wherein at least the laminated electrode is covered with a laminate material. In the assembled battery in which a plurality of laminate-type batteries are electrically joined, the first electrode of the unit cell comprising the laminate-type battery in which the length of the first electrode terminal is longer than that of the second electrode terminal a series junction is the tip portion of the terminal, the series connection of assembled battery is assembled battery in series connection and the distal end portion of the second electrode terminal of another of said unit cells, which are electrically connected to each other , Of the first electrode terminal of each unit cell in the series-connected assembled battery, Serial and parallel joints located between the series junction and the root portion, characterized in that said parallel junction of the other of the series-connected battery pack are electrically joined together.
[0017]
The assembled battery of the present invention configured as described above uses a laminated battery in which the length of the first electrode terminal is longer than that of the second electrode terminal as a single battery, and the first electrode terminal of this single battery constitute the assembled battery in series connection by electrically joining the distal end of the tip and the second electrode terminal of another unit cell. Furthermore, the parallel connection using the parallel connection portion of the first electrode terminal in each unit cell connected in series, that is, the portion other than the serial connection portion which is the connection portion used for the serial connection of the first electrode terminal is performed. Has been made. As described above, in the assembled battery of the present invention, the electrical connection of the first electrode terminals of each unit cell is performed in separate parts for series connection and parallel connection. When the electrode is joined by the thermal stress is not concentrated at one place, the mechanical strength of the electrode is ensured. In addition, since another member for avoiding the contact with different metals is not joined to the electrode, the number of joined parts can be reduced correspondingly, so that an increase in electrical resistance in the electrode can be suppressed and an inexpensive assembly can be achieved. It can be a battery.
[0018]
In addition, the method for manufacturing an assembled battery according to the present invention includes a stacked electrode formed by stacking a first polarity electrode plate and a second polarity electrode plate, and an electric current applied to the first polarity electrode plate. A plurality of first electrode terminals bonded to each other and a second electrode terminal electrically bonded to the electrode plate having the second polarity, wherein at least the laminated electrode is covered with a laminate material. In the method of manufacturing an assembled battery in which the laminate type battery is electrically joined, the step of preparing the laminate type battery in which the length of the first electrode terminal is longer than that of the second electrode terminal; A series junction that is a tip of the first electrode terminal of the unit cell made of the laminate type battery having a length of one electrode terminal longer than the second electrode terminal, and the first of the other unit cell. a battery pack to each other electrically bonded to serially connect the tip of the second electrode terminal A step of producing a series connected assembled battery, a parallel junction located between the series junction and a root of the first electrode terminal of each unit cell in the series connected assembled battery, and another A step of electrically joining the parallel joints of the series-connected assembled battery to each other.
[0019]
In the method of manufacturing the assembled battery of the present invention configured as described above, first, the first electrode terminal is a laminate type battery in which the length of the first electrode terminal is longer than that of the second electrode terminal. The battery pack is joined at the series joint portion to produce a battery pack connected in series. Subsequently, parallel connection is performed using the parallel junction part of the 1st electrode terminal in each single cell of the assembled battery of series connection. That is, in the method for manufacturing an assembled battery according to the present invention, the electrical connection of the first electrode terminals of each unit cell is performed separately in parallel connection in series connection and parallel connection, for example, Even when the electrodes are joined by welding or the like, the thermal stress does not concentrate in one place, so that the mechanical strength of the electrode is hardly lowered. In addition, since there is no step of joining another member to avoid contact with different metals to the electrode, the number of joints and the manufacturing process can be reduced accordingly.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 is a partially broken external perspective view of a laminate type battery unit according to the present invention.
[0023]
A laminate type battery 1 includes a laminated electrode composed of a positive electrode side active electrode 2 and a negative electrode side active electrode 3 laminated via a separator (not shown) by laminating a metal film such as aluminum and a heat fusible resin film. It has a structure sealed with the formed laminate sheet 7.
[0024]
The positive electrode side terminal 4 is electrically joined to the positive electrode side active electrode 2, while the negative electrode side terminal 5 is electrically joined to the negative electrode side active electrode 3. The positive electrode side active electrode 2 and the negative electrode side active electrode 3 are made of different materials. For example, the positive electrode side active electrode 2 is made of an aluminum thin film, and the negative electrode side active electrode 3 is made of a copper thin film.
[0025]
The positive electrode side terminal 4 extends from the first side 10 of the laminate sheet 7 by a length L ₁ , and the negative electrode side terminal 5 extends from the second side 11, which is the side opposite to the first side 10. It extends for a longer length L ₂ than the length L _1.
[0026]
FIG. 2 schematically shows laminated batteries connected in series and in parallel. 2 (a) and 2 (b) are a plan view and a side view, respectively, of an assembled battery of laminate-type batteries connected in series, and FIG. 2 (c) shows a laminate-type battery connected in series. It is a side view of the assembled battery of the state connected in parallel. In FIG. 2A and FIG. 2B, only two laminated batteries 1a and 1b are shown for simplicity. Moreover, the dashed-dotted line in FIG. 2 shows the middle line C between the laminated type batteries connected.
[0027]
The assembled battery 50 shown in FIGS. 2 (a) and 2 (b), in which the laminate type batteries 1 are connected in series, includes the vicinity of the tip of the positive terminal 4a of the laminate type battery 1a and the negative side of the laminate type battery 1b. The vicinity of the tip of the terminal 5b is welded at a position offset by a distance l ₁ from the middle line C between the laminate-type batteries to the side of the laminate-type battery 1a, that is, the tip of the negative-side terminal 5b. (In FIG. 2 (a), x mark, FIG. 2 (b) is indicated by welding A).
[0028]
That is, the assembled battery 50 of the present embodiment in which the laminate type batteries 1 are connected in series is formed by joining two unit cells by only one welding A.
[0029]
FIG. 2 (c) shows an assembled battery in which two series-connected assembled batteries are further connected in parallel.
[0030]
The assembled battery 50 connected in series by joining the vicinity of the tip of the positive electrode side terminal 4a of the laminate type battery 1a to the vicinity of the tip of the negative electrode side terminal 5b of the laminate type battery 1b at one place of welding A. Is configured. Further, the vicinity of the tip of the positive electrode side terminal 4a ′ of the laminate type battery 1a ′ is also joined in series with the vicinity of the tip of the negative electrode side terminal 5b ′ of the laminate type battery 1b ′ by welding A ′. The assembled battery 51 connected to is constituted.
[0031]
In the two battery packs 50 and 51 connected in series, the negative electrode side terminal 5b of the laminate type battery 1b and the negative electrode side terminal 5b 'of the laminate type battery 1b' are substantially on the middle line C between the laminate type batteries. The assembled battery 52 is configured by being joined by welding B. In this state, the positions of the weld A of the assembled battery 50 and the weld A ′ of the assembled battery 51 are offset from the center line C by a distance l ₂ .
[0032]
That is, the assembled battery 52 shown in FIG. 2 (c) has a configuration in which the number of welds between D is three and the number of welds is one less than that of the assembled battery of the same configuration shown in the conventional example. Yes. Thereby, the manufacturing process can be shortened and the manufacturing cost can be reduced. In addition, an increase in the electrical resistance of the electrode can be avoided.
[0033]
Furthermore, in FIG. 2C, for example, the weld A is in the vicinity of the tip of the negative electrode side terminal 5b, the weld B is the position of the weld A of the negative electrode side terminal 5b, and the negative electrode side terminal 5b schematically shown. It is located between the base part 5b1 (in FIG. 1, the part where the second side 11 of the laminate sheet 7 and the negative electrode side terminal 5 overlap). That is, the welding position for series connection is near the tip of each terminal, and the welding position for parallel connection is a position other than the vicinity of the tip of each terminal connected in series. For this reason, concentration of thermal stress during welding can be avoided. Therefore, the mechanical strength of the electrode can be ensured as compared with the conventional example in which welding is concentrated on one point.
[0034]
In addition, in order to prevent the corrosion by the joining of different metals, it is suitable for the junction part of the positive electrode side terminal 4 and the negative electrode side terminal 5 to be coat | covered with resin, for example.
[0035]
In the present embodiment, the length L ₁ of the positive terminal 4 extending from the first side 10 of the laminate sheet 7 is the negative side terminal 5 extending from the second side 11 by the length L _2. However, the present invention is not limited to this, and the positive electrode side terminal 4 may be longer than the negative electrode side terminal 5.
[0036]
However, when welding is performed near the tip of each electrode, it is not desirable to make L _{1 of the} positive terminal 4 equal to L _{2 of the} negative terminal 5. This is because if L ₁ and L ₂ are equal, the positions of the welds A, A ′, and B in FIG. 2C are concentrated on one point. Further, the difference between the lengths L ₁ and L ₂ is preferably such that the distance between the weld A and the weld B and the distance between the weld A ′ and the weld B can be as large as possible.
[0037]
【The invention's effect】
As described above, according to the present invention, a laminate type battery in which the length of the first electrode terminal is longer than that of the second electrode terminal is used as a single battery, and electrode joining is performed separately in series connection and parallel connection. For example, when the electrodes are joined by welding or the like, the thermal stress is not concentrated in one place, and the mechanical strength of the electrode terminals is ensured for a long time. An assembled battery that can withstand use can be provided. In addition, in the manufacturing process, there is no process of joining another member to avoid contact with a different metal to the electrode, and since the number of joints can be reduced, not only the increase in the electrical resistance of the electrode is suppressed, Since the number of manufacturing processes can be reduced, an inexpensive assembled battery can be provided.
[Brief description of the drawings]
FIG. 1 is a partially broken external perspective view of an example of a laminate type battery according to the present invention.
FIG. 2 is a schematic diagram showing serial connection and parallel connection of the laminate type battery shown in FIG. 1;
FIG. 3 is an external perspective view of an example of a flat battery having a conventional laminate material as an exterior body.
FIG. 4 is an external perspective view of an example of a conventional laminated battery in which a copper foil is added to a positive electrode terminal.
FIG. 5 is a schematic diagram showing a series connection and a parallel connection of conventional laminated batteries.
[Explanation of symbols]
1, 1a, 1a ′, 1b, 1b ′ Laminate type battery 2 Positive electrode side active electrode 3 Negative electrode side active electrode 4, 4a, 4a ′ Positive electrode side terminal 5, 5b, 5b ′ Negative electrode side terminal 7 Laminate sheet 10 First side 11 Second side 50, 51, 52 battery pack

Claims (2)

A laminated electrode formed by laminating a first polarity electrode plate and a second polarity electrode plate, a first electrode terminal electrically joined to the first polarity electrode plate, A plurality of laminate type batteries having a second electrode terminal electrically connected to the electrode plate having the second polarity and at least the laminated electrode covered with a laminate material. In assembled batteries,
A series junction part which is a tip part of the first electrode terminal of the unit cell made of the laminate type battery, wherein the length of the first electrode terminal is longer than that of the second electrode terminal, and another unit cell The first electrode of each unit cell in the series-connected assembled battery includes a series-connected assembled battery that is a series-connected assembled battery in which the tip of the second electrode terminal is electrically joined to each other. A battery pack characterized in that a parallel joint portion of the terminal located between the series joint portion and the root portion and the parallel joint portion of the other series-connected battery pack are electrically joined to each other. . A laminated electrode formed by laminating a first polarity electrode plate and a second polarity electrode plate, a first electrode terminal electrically joined to the first polarity electrode plate, A plurality of laminate type batteries having a second electrode terminal electrically connected to the electrode plate having the second polarity and at least the laminated electrode covered with a laminate material. In the method of manufacturing an assembled battery,
Preparing the laminated battery in which the length of the first electrode terminal is longer than that of the second electrode terminal;
A series junction that is the tip of the first electrode terminal of the unit cell made of the laminate type battery and the tip of the second electrode terminal of another unit cell are electrically joined to each other in series. Producing a series-connected assembled battery that is a connected assembled battery;
A parallel junction located between the series junction and the base of the first electrode terminal of each unit cell in the series-connected assembled battery; and the parallel junction of the other series-connected assembled battery And a step of electrically joining the two to each other.

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