JP2004031195A - Laminated cells and battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To interconnect tabs of laminated cells without bending the tabs. <P>SOLUTION: The laminated cells are formed by forming an internal electrode pair 101 by laminating a positive electrode 101a and negative electrode 101b via a separator 101c, sealing the internal electrode pair 101 by an exterior package 10 while being dipped in an electrolyte, respectively joining each layer of the positive electrode 101a and negative electrode 101b to a positive electrode tab 21 and negative electrode tab 22, and protruding the positive electrode tab 21 and the negative electrode tab 22 from the exterior package 10 to the outside. The positive electrode tab 21 is provided in an upper side of the internal electrode pair 101, and the negative electrode tab 22 is provided in a lower side. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a flat laminated battery formed by laminating a positive electrode and a negative electrode, and an assembled battery including a plurality of laminated batteries.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a flat laminated battery in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween to form a laminate, and the laminate is enveloped by an exterior material (for example, JP-A-2002-42865). ). In this type of laminated battery, a positive electrode tab and a negative electrode tab are respectively protruded from the exterior material on the same plane, and the positive electrode tab and the positive electrode and the negative electrode tab and the negative electrode are respectively bonded.
[0003]
[Problems to be solved by the invention]
When such a laminated battery is used as a secondary battery of an electric vehicle or a hybrid vehicle, a plurality of laminated batteries are stacked, and tabs are connected in the stacking direction to form an assembled battery. However, since the positive electrode tab and the negative electrode tab of the conventional laminated battery are on the same plane, for example, when the positive electrode tab and the negative electrode tab are stacked in an alternate direction and the laminated batteries are connected in series, the upper layer tab (for example, the positive electrode tab) ) And a lower layer tab (for example, a negative electrode tab) by the thickness of the laminated battery. Therefore, in order to electrically connect the upper tab and the lower tab, it is necessary to bend the tab by the thickness of the laminated battery. When the tab is bent, a load acts on the joint between the tab and the exterior material, causing leakage of the electrolyte sealed in the exterior material.
[0004]
An object of the present invention is to provide a laminated battery and a battery pack that can easily join tabs of a stacked battery without bending the tabs.
[0005]
[Means for Solving the Problems]
In the present invention, a positive electrode and a negative electrode are stacked in a plurality of layers vertically through a separator, and the laminate is immersed in an electrolytic solution and sealed with an outer package. This is a laminated battery which is joined to a positive electrode tab and a negative electrode tab, and the positive electrode tab and the negative electrode tab are projected from the outer package. The object described above is achieved by providing a tab of the first polarity on one side of the upper and lower surfaces of the laminate and providing a tab of a second polarity opposite to the first polarity on the other side of the upper and lower surfaces of the laminate. I do.
In addition, a plurality of the laminated batteries are stacked so that the positive electrode tab and the negative electrode tab face alternately in one direction, and a housing for accommodating the plurality of laminated batteries and an intervening member are provided between the laminated batteries. Thus, an assembled battery can be constituted by a plurality of bus bars that electrically connect the upper electrode tab of the first polarity and the electrode tab of the second polarity having a polarity opposite to the first polarity of the lower layer.
Further, the laminated batteries are arranged side by side in the same plane in the first direction to form a first parallel battery group, and are arranged in the same plane in the second direction opposite to the first direction. To form a second parallel battery group, and the first parallel battery group and the second parallel battery group are each provided between the first parallel battery group and the second parallel battery group. A bus battery group is formed by arranging bus bar groups connected in parallel and in series with a flat plate, and stacking the first parallel battery group, the second parallel battery group, and the bus bar group alternately and housing them in a housing. be able to.
[0006]
【The invention's effect】
According to the present invention, a tab having a first polarity is provided on one side of the upper and lower surfaces of a stacked body formed by laminating a positive electrode and a negative electrode, and a tab having a second polarity having a polarity opposite to the first polarity is provided on the other side. With this configuration, the tabs of the stacked batteries can be easily joined without bending the tab.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a laminated battery according to the present invention will be described with reference to FIGS.
First, the configuration of a single unit of the laminated battery will be described. FIG. 1 is a plan view showing the external shape of the laminated battery according to the present embodiment, and FIG. 2 is a side view. In the following, for convenience of description, the upper, lower, left, and right directions are defined as shown in FIG. The laminated battery 1 includes an outer package 10 made of a pair of upper and lower flexible exterior members 11 and 12 having a substantially rectangular shape in a plan view, and a positive electrode tab 21 and a negative electrode tab 22 protruding from left and right ends of the outer package 10, respectively. Is a sheet-shaped lithium ion secondary battery having:
[0008]
FIG. 3 is a perspective view of the exterior materials 11 and 12. As shown in FIG. 3, the exterior materials 11 and 12 are provided with bulging portions 110 and 120 which bulge upward and downward from the surrounding flange surfaces 11a to 11c and 12a to 12c, respectively. The bulging portions 110 and 120 have horizontal surfaces 110a and 120a and vertical surfaces 110b and 120b, respectively.
[0009]
The flange surfaces 11a and 12a of the exterior materials 11 and 12 are provided obliquely in a side view (see FIG. 2), the left end flange surfaces 11b and 12b of the exterior materials 11 and 12 are located at the bottom, and the right end flange surfaces 11c and 12c. Is formed at the top. Tabs 21 and 22 are sandwiched between the flange surfaces 11b and 12b and 11c and 12c, respectively, and the tabs 21 and 22 are located on upper and lower sides. The upper and lower surfaces of the tabs 21 and 22 and the flange surfaces 11b, 12b, 11c and 12c, and the flange surface 11a of the exterior material 11 and the flange surface 12a of the exterior material 12 are welded to each other. An enclosed space is formed.
[0010]
FIG. 4 is a diagram showing the internal shape of the laminated battery 1 (a cross-sectional view taken along the line IV-IV in FIG. 1), and FIG. 5 is an enlarged view of a portion V in FIG. Inside the outer package 10, an internal electrode pair 101 and an electrolytic solution 102 are housed in a vacuum-sealed state. The internal electrode pair 101 includes a sheet-like positive electrode 101a and a negative electrode 101b.
[0011]
The positive electrode 101a is obtained by laminating a positive electrode active material on both surfaces of a positive electrode current collector 104 made of aluminum foil. On the other hand, the negative electrode 101b is formed by laminating a negative electrode active material on both surfaces of a negative electrode current collector 105 made of copper foil. The positive electrode 101a and the negative electrode 101b are alternately stacked with a separator 101c interposed therebetween, and the internal electrode pair 101 forms a stacked body. Aluminum, an aluminum alloy, or the like is used for the positive electrode tab 21, and copper, a copper alloy, or the like is used for the negative electrode tab 22.
[0012]
The positive electrode tab 21 air-tightly penetrates the left end 103 of the outer package 10, and the tip is close to the left end face of the internal electrode pair 101. The negative electrode tab 22 air-tightly penetrates the right end portion 106 of the outer package 10, and its tip is close to the right end surface of the internal electrode pair 101. Each positive electrode 101a is welded to the upper surface of the tip of the positive electrode tab 21. On the other hand, although not shown in an enlarged manner, each negative electrode 101b is welded to the lower surface of the distal end portion of the negative electrode tab 22, respectively.
[0013]
The bag-shaped outer package 10 is formed of a three-layer laminated film of an inner layer 10a, an intermediate layer 10b, and an outer layer 10c. For the inner surface layer 10a, a thermoplastic resin such as polyethylene, polypropylene, or polyamide having excellent resistance to electrolyte and heat sealing is used. For the intermediate layer 10b, a metal foil having excellent flexibility and strength, such as an aluminum foil or a stainless steel foil, is used. For the outer surface layer 10c, an insulating resin having excellent electric insulation such as a polyamide resin or a polyester resin is used.
[0014]
Next, an example in which a plurality of laminated batteries according to the present invention are used as an assembled battery will be described with reference to FIGS.
(1) Series connection First, an example in which the laminated batteries 1 are connected in series will be described. 6 is a cross-sectional view showing the internal shape of the battery pack, FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6, and FIG. 8 is a perspective view of a main part. The assembled battery is used, for example, as a secondary battery of an electric vehicle or a hybrid vehicle.
[0015]
As shown in FIGS. 6 and 7, a total of 16 laminated batteries 1, that is, two horizontal rows, eight upper and lower rows, and a total of 16 laminated batteries 1 are accommodated in the substantially rectangular parallelepiped container 30. The battery case 30 is formed of an insulating material such as a resin. As shown in FIG. 8, the laminated batteries 1 arranged side by side in the horizontal direction are arranged in a state where they are inverted by 180 degrees from each other. That is, the left and right tabs 21 and 22 of the laminated batteries 1 arranged side by side are located on the same plane, but have different polarities. The laminated batteries 1 arranged side by side are stacked while being rotated alternately by 180 degrees in the horizontal direction so that the odd-numbered stages and the even-numbered stages face in opposite directions, and the positive electrode tab 21 and the negative electrode tab 22 are arranged adjacent to each other in the laminating direction. Have been.
[0016]
Conductive bus bars 32 to 35 are disposed between the positive electrode tab 21 and the negative electrode tab 22 of the laminated laminated battery 1, the lower surface of the lowermost laminated battery 1, and the upper surface of the uppermost laminated battery, respectively. Have been.
[0017]
As shown in FIG. 8, the bus bars 32 extend so as to cover the entire surface of the single laminated battery 1 so as to prevent lateral connection of the laminated batteries 1 arranged side by side. The positive and negative electrode tabs 21 and 22 of the laminated battery 1 are respectively connected to the upper and lower surfaces of the bus bar 32, and the laminated batteries 1 are vertically connected in series via the bus bar 32. The connection between the bus bars 32 to 35 and the tabs 21 and 22 is fixed by welding or the like.
[0018]
The bus bar 33 extends over a pair of laminated batteries 1 arranged side by side at the bottom. On the upper surface of the bus bar 33, the positive electrode tab 21 of the laminated battery 1 and the negative electrode tab 22 of the laminated battery 1 arranged side by side are connected, respectively. They are connected in series.
[0019]
The bus bar 34 extends so as to cover the entire upper surface of one of the laminated batteries 1 arranged side by side at the top, and the bus bar 35 extends so as to cover the entire upper surface of the other laminated battery 1. The bus bar 34 is connected to the positive electrode tab 21 of the laminated battery 1 therebelow, and the bus bar 35 is connected to the negative electrode tab 22 of the laminated battery 1 therebelow. The ends of the bus bars 34 and 35 are bent upward, and penetrate the upper lid 30 a of the battery case 30 and protrude outside the battery case 30. The protruding bus bars 34 and 35 form a plus terminal and a minus terminal of the assembled battery, respectively. A sealing material 37 is injected into a gap between the bus bars 34 and 35 and the upper lid 30a.
[0020]
As described above, the laminated batteries 1 are connected in series in the battery case 30 via the bus bars 32 to 35 to form an assembled battery. In this case, as shown in FIG. 6, the tab of the lower laminated battery 1 (for example, the positive electrode tab 21) is located at the upper part, and the tab of the upper laminated battery 1 (for example, the negative electrode tab 22) is located at the lower part. , 22 can be connected to the bus bar 32 without bending. Also, since the positive electrode tab 21 of the lowermost pair of laminated batteries 1 and the negative electrode tab 22 of the laminated battery 1 arranged side by side are both located at the bottom, the tabs 21 and 22 are also bent at the lowermost level without being bent to the bus bar 33. Can be connected. Furthermore, since the positive electrode tab 21 of the uppermost laminated battery 1 and the negative electrode tab 22 of the laminated battery 1 arranged side by side are both located at the upper part, the tabs 21 and 22 are not bent at the uppermost stage without being bent to the bus bars 34 and 35. Can be connected.
[0021]
A compression member 36 is provided between the bus bars 34 and 35 and the upper lid 30a of the battery case 30. The compression member 36 is made of an elastic material such as urethane foam, and the upper lid 30a is bolted to the battery case main body 30b via the compression member 36, and each laminated battery 1 in the battery case 30 is pressed downward. In this case, since the surface of the laminated battery 1 is covered with the bus bars 32 to 35, the pressing force acts on the entire internal electrode pair 101 in the laminated battery 1. As a result, a local change in the distance between the electrodes 101a and 101b can be prevented, and stable battery performance can be obtained. The compression member 36 may be fixed to the upper lid 30a in advance.
[0022]
When assembling the assembled battery, first, the bus bars 32 to 35 and the laminated battery 1 are welded and integrated. Then, this integrated product is installed in the battery case 30, and the upper lid 30a is bolted to the battery case body 30b via the pressing member 36.
[0023]
(2) Parallel connection Next, an example in which the laminated batteries 1 are connected in series will be described. 9 is a cross-sectional view showing the internal shape of a battery pack formed by connecting the laminated batteries 1 in parallel and in series, FIG. 10 is a cross-sectional view taken along line XX of FIG. 9, and FIG. 11 is a perspective view of a main part.
[0024]
As shown in FIGS. 9 and 10, a total of 32 laminated batteries 1 are accommodated in the battery case 30 in four rows and eight rows vertically. As shown in FIG. 11, of the four rows of laminated batteries 1, two rows on one side are arranged in the same direction, and the two rows and the remaining two rows are arranged in a state of being inverted by 180 degrees from each other. The four rows of laminated batteries 1 are stacked while being rotated alternately by 180 degrees in the horizontal direction so that the odd-numbered stages and the even-numbered stages face in opposite directions, and the positive electrode tab 21 and the negative electrode tab 22 are arranged adjacent to each other in the stacking direction. ing.
[0025]
Bus bars 42 to 45 are interposed between the positive electrode tab 21 and the negative electrode tab 22 of the laminated laminated battery 1, the lower surface of the lowermost laminated battery 1, and the upper surface of the uppermost laminated battery 1, respectively. ing.
[0026]
As shown in FIG. 11, the bus bar 42 extends over the entire surface of the two rows of laminated batteries 1 of the four rows of laminated batteries 1. On the upper and lower surfaces of the bus bar 42, the positive electrode tabs 22 or the negative electrode tabs 22 of the laminated batteries 1 arranged in parallel are connected in parallel, and the tabs of the lower laminated battery 1 (for example, the positive electrode tab 21) and the upper laminated battery One tab (for example, the negative electrode tab 22) is connected in series. That is, the laminated batteries 1 are connected in series and parallel via the bus bar 42.
[0027]
The bus bar 43 extends over all of the four rows of laminated batteries 1 arranged at the bottom. On the upper surface of the bus bar 43, the positive electrode tab 21 of the two rows of laminated batteries 1 on one side and the negative electrode tab 22 of the laminated battery 1 on the opposite side are connected, respectively, and the lowermost laminated batteries 1 are arranged in parallel via the bus bar 33. It is connected.
[0028]
The bus bar 44 extends so as to cover the entire upper surface of the two rows of laminated batteries 1 arranged side by side at the top, and the bus bar 45 extends so as to cover the entire upper surface of the laminated batteries 1 arranged in the opposite two rows. I have. The bus bar 44 is connected to the positive electrode tab 21 of the laminated battery 1 below, and the bus bar 45 is connected to the negative electrode tab 22 of the laminated battery 1 below. The ends of the busbars 44 and 45 are bent upward, and penetrate the upper lid 30 a of the battery case 30 and protrude outside the battery case 30. The protruding bus bars 44 and 45 form a plus terminal and a minus terminal of the assembled battery, respectively. A sealing material 37 is injected into a gap between the bus bars 44 and 45 and the upper lid 30a.
[0029]
As described above, the laminated batteries 1 are connected in parallel and series in the battery case 30 via the bus bars 42 to 45 to form an assembled battery. In this case, as shown in FIG. 9, the tab (for example, the positive electrode tab 21) of the lower laminated battery 1 is located at the upper part, and the tab (for example, the negative electrode tab 22) of the upper laminated battery 1 is located at the lower part. , 22 can be connected to the bus bar 42 without bending. Also, since the positive electrode tabs 21 of the lowermost two rows of laminated batteries 1 and the negative electrode tabs 22 of the two rows of laminated batteries 1 arranged side by side are both located at the lower part, the tabs 21 and 22 may also be bent at the lowermost level. And can be connected to the bus bar 33 without the need. Furthermore, since the positive electrode tabs 21 of the two rows of laminated batteries 1 in the uppermost row and the negative electrode tabs 22 of the two rows of laminated batteries 1 arranged in parallel with each other are located at the upper part, the tabs 21 and 22 are also bent at the uppermost row. And can be connected to the busbars 44 and 45 without the need.
[0030]
A compression member 46 is provided between the bus bars 44 and 45 and the upper lid 30a of the battery case 30. The compression member 46 is made of an elastic material such as urethane foam, and the upper lid 30a is bolted to the battery case main body 30b via the compression member 46, and each laminated battery 1 in the battery case 30 is pressed downward. In this case, since the surface of the laminated battery 1 is covered with the bus bars 42 to 45, the pressing force acts on the entire internal electrode pair 101 in the laminated battery 1. As a result, a local change in the distance between the electrodes 101a and 101b can be prevented, and stable battery performance can be obtained.
[0031]
According to the embodiment described above, the following effects can be obtained.
(1) The positive electrode tab 21 is provided on one side in the thickness direction (lamination direction) of the laminated battery 1 and the negative electrode tab 22 is provided on the other side. This makes it possible to connect the tabs 21 and 22 to each other via the bus bars 32 and 42 without bending the tabs 21 and 22 when forming a battery pack by stacking a plurality of the laminated batteries 1, thereby preventing liquid leakage.
(2) Since the tabs 21 of the laminated battery 1 are not on the same plane, the tabs are respectively protruded from the left and right ends of the outer package 10 to cover the upper and lower surfaces of the laminated battery 1 with the bus bars 32, 42. However, short-circuiting of the tabs 21 and 22 can be prevented.
(3) Since the flange surfaces 11a, 12a of the exterior materials 11, 12 are provided obliquely and the flange surfaces 11b, 12b and 11c, 12c at the left and right ends are provided up and down, a pair of upper and lower exterior materials 11, 12 are used. The height of the tabs 21 and 22 can be easily shifted.
(4) Since the flange surfaces 11a to 11c and 12a to 12c of the exterior members 11 and 12 are not on the same plane, the mechanical strength of the outer package 10 is improved.
(5) Since the positive electrode tab 21 and the negative electrode tab 22 are provided on the upper and lower portions of the laminated battery 1 respectively, the connection between the tabs 21 and 22 and the bus bars 32 and 42 is easy, and a plurality of laminated batteries 1 can be stacked. Thus, a series-connected battery pack or a parallel-series connected battery pack can be easily formed.
(6) Since the bus bars 32 and 42 are provided so as to cover the surface of the laminated battery 1, the entire surface of the laminated battery 1 can be uniformly pressed through the bus bars 32 and 42.
[0032]
The laminated battery according to the present invention can be variously modified without being limited to the above embodiment. In the above description, the positive electrode tab 21 and the negative electrode tab 22 are made to protrude from both left and right sides of the laminated battery 1. However, if they extend in two planes in the thickness direction (the laminating direction) of the laminated battery 1, one side may be left and right. May be made to protrude. Although the bus bars 32 and 42 are provided over the entire surface of the laminated battery 1, the bus bars 32 and 42 may be provided only on the tabs 21 and 22 and the entire surface of the laminated battery 1 may be pressed by a member different from the bus bars 32 and 42. Good.
[0033]
In the above embodiment, the exterior members 11 and 12 constitute a superposed member. Also, as shown in FIG. 11, one of the laminated battery groups arranged in two rows (for example, the upper row) corresponds to the first parallel battery group, and the other (for example, the lower row) corresponds to the second parallel battery group. The bus bar 42 constitutes a bus bar group. Although the laminated batteries 1 are connected in parallel in two rows, three or more rows may be connected in parallel to form a parallel battery. The shape of the battery case 30 as a housing may be any shape. The tabs 21 and 22 can be joined to the electrodes 101a and 101b and the bus bars 32 to 35 by a method other than welding (for example, brazing or a heat-resistant adhesive).
[Brief description of the drawings]
FIG. 1 is a plan view showing the external shape of a laminated battery according to an embodiment of the present invention.
FIG. 2 is a side view showing an external shape of the laminated battery according to the embodiment of the present invention.
FIG. 3 is a perspective view of an exterior material constituting the laminated battery according to the embodiment of the present invention.
FIG. 4 is a sectional view taken along line IV-IV of FIG. 1;
FIG. 5 is an enlarged view of a portion V in FIG. 4;
FIG. 6 is a sectional view of an assembled battery formed by connecting laminated batteries in series.
FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;
FIG. 8 is a perspective view of a main part of FIG. 6;
FIG. 9 is a sectional view of an assembled battery formed by connecting laminated batteries in parallel and in series.
FIG. 10 is a sectional view taken along line XX of FIG. 9;
FIG. 11 is a perspective view of a main part of FIG. 9;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laminated battery 10 Outer package 11 Exterior material 11a-11c Flange surface 12 Exterior material 12a-12c Flange surface 21 Positive electrode tab 22 Negative electrode tab 30 Battery case 32-35 Bus bar 42-45 Bus bar 36,46 Compression material 101 Internal electrode pair 101a Positive Electrode 101b Negative electrode 101c Separator

Claims (5)

A positive electrode and a negative electrode are laminated in a plurality of layers vertically through a separator, and the laminate is immersed in an electrolytic solution and sealed with an outer package.The positive electrode and the negative electrode of each layer are respectively separated into a positive electrode tab and a negative electrode. Bonded to a tab, a laminated battery formed by projecting the positive electrode tab and the negative electrode tab from the outer package,
A laminated battery comprising: a first polarity tab provided on one of upper and lower surfaces of the laminate; and a second polarity tab having a polarity opposite to the first polarity provided on the other upper and lower surfaces of the laminate. . The laminated battery according to claim 1,
The exterior material is a sealed container in which a pair of upper and lower overlapping members having a substantially rectangular shape in a plan view are overlapped with an outer peripheral flange portion, and the flange portion is welded,
The laminated battery according to claim 1, wherein the positive electrode tab and the negative electrode tab are sandwiched by the flange and protrude in opposite directions. The laminated battery according to claim 1 or 2, wherein a plurality of the positive electrode tabs and the negative electrode tabs are stacked so as to be alternately oriented in one direction,
A housing for accommodating the plurality of laminated batteries;
A plurality of bus bars interposed between the laminated batteries and electrically connecting an upper electrode tab having a first polarity and a lower electrode tab having a second polarity opposite to the first polarity; A battery pack comprising: A first parallel battery group comprising a plurality of the laminated batteries according to claim 1 or 2 arranged side by side in the same plane in a first direction to form a parallel battery;
A second parallel battery group, wherein the plurality of laminated batteries according to claim 1 or 2 are arranged side by side in the same plane in a second direction opposite to the first direction to form a parallel battery,
The first parallel battery group and the second parallel battery group are interposed between the first parallel battery group and the second parallel battery group, and the first parallel battery group and the second parallel battery group are connected in parallel and in series by one flat plate. Busbars,
An assembled battery comprising: a housing for alternately stacking and housing the first parallel battery group, the second parallel battery group, and the bus bar group. The battery pack according to claim 4,
A bus bar interposed between the first parallel battery group and the second parallel battery group is
Tabs of a first polarity of the plurality of laminated batteries of the first parallel battery group are connected in parallel, and tabs of a second polarity of the second parallel battery group are connected in parallel. An assembled battery, wherein tabs of a second polarity of a group and tabs of a first polarity of a second parallel battery group stacked on the first parallel battery group are connected in series.

Images