JP2004119043A - Battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack in which the outside dimension is made as small as possible by enabling to arrange the batteries efficiently in the case body of the battery pack. <P>SOLUTION: In the battery pack 1, the connecting member 4 is formed in belt-shape by metal plate and a bent part 4c or a curved part which protrudes on one face side is provided beforehand at the intermediate portion, and by this connecting member, the electrodes 3c, 3d of the two batteries 3, 3 which are positioned opposed to each other are connected in the case body. Therefore, the connecting member is made not to protrude outside than the outer edge of the battery. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery pack used as a power source for electronic devices and the like. More specifically, the present invention relates to a technique for efficiently arranging batteries inside a battery pack to reduce the outer dimensions of the battery pack.
[0002]
[Prior art]
In recent years, demand for portable electronic devices such as portable radio telephone devices, portable personal computers, and portable video cameras has been rapidly increasing. In such portable electronic devices, small sealed secondary batteries such as nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries are widely used as power sources. In particular, lithium-ion batteries have characteristics such as high voltage, high energy density, and light weight that are suitable for use in portable electronic devices, and are used in a wide variety of applications in various devices including portable electronic devices. Have been.
[0003]
The sealed small secondary battery (hereinafter referred to as “battery”) has been commercialized as a so-called cylindrical battery having a columnar shape or a so-called prismatic battery having a prismatic or flat rectangular parallelepiped shape, and has been used in the above various devices. When used, they are often used as so-called battery packs in which a plurality of them are put together.
[0004]
The battery pack accommodates a plurality of batteries in a case body made of, for example, polycarbonate (PC) or acrylonitrile butadiene styrene (ABS) and electrically connects the batteries so that electric power can be extracted from the outside. It is composed.
[0005]
FIG. 11 shows an example a of a conventional battery pack. The battery pack a is configured such that two batteries c, c electrically connected to each other are arranged and housed in a case body b, and the power stored in the batteries c, c can be taken out from the outside. . Each of the batteries c and c is a rectangular battery having a flat rectangular parallelepiped shape, and one positive electrode c3 and one negative electrode c4 are provided on each of end faces c1 and c2 in the longitudinal direction.
[0006]
In the following description, when describing the arrangement state of the batteries, it is referred to as arranging a plurality of batteries so that their electrodes face each other and arranging the batteries so that the electrodes facing each other are connected to each other. (The same applies to the embodiments described later).
[0007]
In the case body b, the batteries c and c are vertically arranged, and the electrodes c3 and c4, which are opposed to each other, are connected to a connecting member (hereinafter, referred to as a "tab") made of a thin metal plate as shown in FIG. .) D. The batteries c and c are connected to a connection member (not shown) or the like, so that electric power can be taken out.
[0008]
The connection between the electrodes c3 and c4 of the batteries c and c located opposite to each other and the tab d is made by, for example, welding.
[0009]
The connection between the electrodes c3 and c4 of the batteries c and c is performed in order to improve the workability by performing the connection work of the tab d by welding or the like from the same direction. In order to reduce the size, for example, as shown in FIG. 12, two batteries c, c are arranged in parallel with the surfaces on which electrodes are not formed facing each other. The batteries c, c are vertically arranged in the case body b by bending the middle part d1 of the tab d.
[0010]
That is, as shown in FIG. 12, after the adjacent electrodes c3 and c4 are connected by the tab d, one of the batteries c is shown by the solid line from the state shown by the two-dot chain line in FIG. Rotate about 180 ° until it is in a state. Due to the rotation of the one battery c, the intermediate portion d1 of the tab d is curved, and the entire tab d has a substantially U-shaped shape. Then, the curved intermediate portion d1 of the tab d projects outward from the outer edges c5, c5 of the batteries c, c, as shown in FIGS.
[0011]
[Problems to be solved by the invention]
By the way, with the miniaturization of electronic devices, it is required to reduce the external dimensions even in battery packs.
[0012]
The external dimensions of the battery pack a can be reduced by reducing the size of the batteries c and c stored in the case body b. However, when the size of the batteries c and c is reduced, the storage capacity thereof also decreases, and the time that can be used in a single charge in an electronic device or the like that uses the battery pack a as a power source also decreases in proportion to this. Will be. Further, it is not easy to reduce the size of the batteries c and c without changing the storage capacity.
[0013]
Therefore, it is required to reduce the outer dimensions of the battery pack a without reducing the storage capacity. To this end, it is effective to reduce the volume occupied by the batteries c and c other than the total volume in the case body b of the battery pack a, for example, to eliminate useless space in the case body b. Seem.
[0014]
However, in the battery pack a, the volume occupied by the components other than the batteries c and c cannot be reduced in the total volume in the case body b.
[0015]
That is, in the case body b, for the above-described reason, when the batteries c, c are arranged vertically, the middle part d1 is bent by the curved tab d to form the electrodes c3 and c4 opposed to the batteries c, c. 11, the intermediate portion d1 of the tab d projects outward beyond the outer edge c5 of the batteries c and c, and the batteries c and c are protruded by the projecting intermediate portion d1, as shown in FIGS. Extra space is required in addition to the space to be placed.
[0016]
Therefore, the batteries c, c,... Cannot be efficiently arranged in the case body b, and the volume of the case body b becomes uselessly large, and it is difficult to reduce the external dimensions of the battery pack a. Was. Further, if it is difficult to reduce the size of the battery pack a, it also becomes an obstacle to downsizing of the electronic device.
[0017]
In view of the above problems, an object of the battery pack of the present invention is to provide a battery pack in which external dimensions can be made as small as possible so that batteries can be efficiently arranged in a case body of the battery pack.
[0018]
[Means for Solving the Problems]
In order to solve the above problems, the battery pack of the present invention has a connecting member formed in a band shape with a metal plate, and has a bent portion or a curved portion which is previously protruded to one surface side in an intermediate portion, and a case is formed by the connecting member. By connecting the electrodes of the two batteries facing each other in the body, the connection member is prevented from protruding outside the outer edge of the batteries.
[0019]
Therefore, in the battery pack of the present invention, the connection member does not protrude outward from the outer edge of the battery when the battery is vertically disposed in the case body.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the battery pack of the present invention will be described with reference to the accompanying drawings. In the present embodiment, the present invention is applied to a battery pack using a plurality of so-called prismatic lithium ion secondary batteries. The present invention can be applied to a battery pack using a cylindrical battery or a battery of another shape.
[0021]
1 to 3 show a first embodiment 1 of the battery pack of the present invention.
[0022]
As shown in FIG. 1, the battery pack 1 arranges and stores two batteries 3, 3 electrically connected to each other in a case body 2, so that the power stored in these batteries 3, 3 can be taken out from the outside. It is comprised in. The batteries 3, 3 are rectangular batteries having a flat rectangular parallelepiped shape, and one positive electrode 3c and one negative electrode 3d are provided on end surfaces 3a, 3b in the longitudinal direction, respectively.
[0023]
In the case body 2, the batteries 3 and 3 are arranged vertically, and electrodes 3c and 3d located opposite to each other are connected to a connecting member (hereinafter referred to as a "tab") made of a thin metal plate as shown in FIG. .) 4. The batteries 3, 3 are connected to connection members other than the tab 4 (not shown), external terminals, and the like, so that power can be extracted to the outside.
[0024]
As shown in FIG. 2, the tab 4 has a long band shape in one direction, and both end portions 4a and 4b serve as connecting portions with the electrodes 3c or 3d of the batteries 3 and between the connecting portions 4a and 4b. Are bent portions 4c which are bent so as to form a shape in which a plurality of V-shapes are continuous. The bent portion 4c is formed so as to protrude on one surface side of the tab 4. Note that the shape of the bent portion 4c is not limited to a shape in which a plurality of V-shapes are continuous, and may be a simple V-shape or the like.
[0025]
As described above, when the bent portion 4c of the tab 4 is formed in the shape described above, if the tab d has no bent portion, the two batteries c and c are vertically arranged as shown in FIG. At this time, the intermediate portion d1 is curved, and the curved intermediate portion d1 protrudes outward from the outer edges of the batteries c, c. By providing the bent portion 4c, the intermediate portion of the tab 4 allows the battery 3, 3 Are prevented from projecting outward beyond the outer edges 3e, 3e. Therefore, the middle portion of the tab 4 is not limited to the bent portion 4c having a shape in which the plurality of V-shaped portions are connected or a V-shaped shape. It may be a curved portion that is curved so that In short, any shape may be used as long as it does not protrude outside the outer edges 3e, 3e of the vertically arranged batteries 3, 3.
[0026]
The connection between the tabs 4 and the electrodes 3c and 3d of the batteries 3 and 3 facing each other is made by, for example, welding.
[0027]
When connecting the batteries 3 and 3 using the tab 4, the tab 4 is connected by welding or the like from the same direction to improve workability. In order to reduce resistance and the like, connection between the electrodes 3c and 3d by the tab 4 is made as follows.
[0028]
First, as shown in FIG. 3, the two batteries 3 are arranged in parallel with the surfaces on which the electrodes 3c and 3d are not formed facing each other.
[0029]
Then, as shown in FIG. 3, the tab 4 is positioned so that the bent portion 4c projects outwardly from the end surfaces 3a, 3b of the batteries 3, 3, and the adjacent electrodes 3c, The connecting portions 4a and 4b of the tab 4 are connected to 3d, respectively. Therefore, one battery 3 is rotated about 180 ° in the direction of arrow A from the state shown by the solid line to the state shown by the dashed line in FIG. The tab 4 is further bent in the same direction as the direction in which the boundary portions 4d and 4e between the bent portions 4c and the connection portions 4a and 4b were bent by the rotation of the one battery 3, and the connection portions 4a and 4b were bent. It is located in parallel and the bent portion 4c is sandwiched between the connecting portions 4a and 4b. As described above, the tabs 4 only change the bending angles of the boundary portions 4d and 4e between the bent portions 4c and the connection portions 4a and 4b, even if the batteries 3 and 3 are arranged vertically. There are no new bends or curves.
[0030]
Therefore, since the bent portion 4c of the tab 4 does not protrude outside the outer edges 3e, 3e of the batteries 3, 3, the space occupied by anything other than the batteries 3, 3 in the case body 2 can be reduced. . After the batteries 3 and 3 are arranged vertically, as shown by arrows B and C in FIG. 3, by applying a force in a direction in which the batteries 3 and 3 approach each other, the bent portion of the bent portion 4c of the tab 4 is bent. It is further bent to make the distance between the end face 3a of one battery 3 and the end face 3b of the other battery 3 as small as possible, and further, the space occupied by anything other than the batteries 3 in the case body 2. Can also be reduced.
[0031]
By the way, in the battery pack 1, the tabs 4 for connecting the vertically arranged batteries 3, 3 are not bent at all from the beginning, but are initially flat and the electrodes 3c, 3d of the batteries 3, 3 are not bent. , Respectively, and then the bent portion 4c can be formed. In this case, after connecting the connecting portions 4a and 4b to the electrodes 3c and 3d of the batteries 3 and 3, respectively, the tab 4 forms the bent portion 4c using a jig or a machine. As a result, the number of steps for assembling the battery pack 1 increases. Therefore, it is desirable to form the bent portion 4c on the tab 4 in advance. The same applies to a tab in a battery pack according to a second embodiment described later.
[0032]
4 to 10 show a second embodiment 1A of the battery pack of the present invention. In this embodiment, a battery having a positive electrode on one end face in the longitudinal direction and a negative electrode on the other end face is used.
[0033]
As shown in FIGS. 4 and 5, the battery pack 1 </ b> A has six flat rectangular parallelepiped rectangular batteries 11, 11 electrically connected in a case body 10 including an upper case 10 a and a lower case 10 b. ,... Are arranged and housed so that the electric power stored in these batteries 11, 11,. Are three batteries 11 arranged vertically in the case body 10. Each of the batteries 11, 11,...
[0034]
Each of the batteries 11, 11,... Is provided with a positive electrode 11c on one end surface 11a and a negative electrode 11d on the other end surface 11b in the longitudinal direction, as shown in FIGS. , 11d are electrically connected to another battery 11, a printed wiring board described later, and the like.
[0035]
In the case body 10, as shown in FIGS. 5 and 6, each of the batteries 11, 11,... Has eleven connection members 12a, each of which has predetermined electrodes 11c, 11d formed by bending a thin metal plate. 12b, 12c, 12d, 12e, 12f, 12g, and 12h (each having a different shape) and connecting members 13, 13, 13 (hereinafter, only connecting members 13, 13, 13 are referred to as "tabs"). Each is electrically connected so as to have a connection relationship. The connecting members 12a to 12h and the tabs 13, 13, 13 are connected to the electrodes 11c, 11c,..., 11d, 11d,. Connected appropriately.
[0036]
In three places indicated by D, E and F in FIG. 6, two electrodes 11c and 11d, 11c and 11d and 11c of the batteries 11, 11,... 11c are connected to each other by three tabs 13, 13, 13 having the same shape.
[0037]
As shown in FIG. 7, the tab 13 is formed by bending a middle portion of a thin metal plate having a horizontally long H shape. Further, the tab 13 is a middle portion in which the wide portions 13a and 13b at both ends serve as connection portions with the electrodes 11c or 11d of the batteries 11 and the width between the connection portions 11a and 11b is reduced. A bent portion 13c is formed so as to have a shape in which a plurality of V-shaped characters are continuously formed. The shape of the bent portion 13c is not limited to a shape in which a plurality of V-shapes are continuous, and may be a simple V-shape.
[0038]
In addition, the intermediate portion between the connection portions 13a and 13b of the tab 13 is not limited to the bent portion 13c having a shape in which a plurality of V-shaped characters are connected or a V-shaped shape. It may be a curved portion that is curved so as to protrude to one surface side of the tab 13. In short, any shape may be used as long as it does not protrude outward from the outer edges 11e of the batteries 11 arranged vertically.
[0039]
When connecting the batteries 11 and 11 using the tabs 13, the tabs 13 can be connected by welding or the like from the same direction to improve workability. In order to reduce resistance and the like, connection between the electrodes 11a and 11b by the tab 13 is made as follows.
[0040]
First, as shown in FIG. 8, the surfaces of the two batteries 11, 11 on which the electrodes 11 c, 11 d (or 11 c) are not formed face each other, and the electrodes 11 c and 11 d or 11 c and 11 c are as close as possible. And arrange them in parallel.
[0041]
Then, as shown in FIG. 8, the tab 13 is placed on the electrodes 11 c and 11 d of the batteries 11 and 11 in a direction in which the bent portion 13 c is positioned so as to protrude outward from the end surfaces 11 a and 11 b of the batteries 11 and 11. The connecting portions 13a and 13b of the tab 13 are connected respectively. Therefore, both batteries 11, 11 are rotated by 90 ° as shown by arrows K and L in FIG. This rotation may be performed by rotating only one battery 11 by 180 °.
[0042]
By the rotation of the one battery 11, the tab 13 is further bent in the same direction as the direction in which the boundary portions 13d and 13e between the bent portion 13c and the connection portions 13a and 13b were originally bent, and the connection portions 13a and 13b were bent. They are located in parallel and the bent portion 13c is sandwiched between the connecting portions 13a and 13b. As described above, the tabs 13 only change the bending angles of the boundary portions 13d and 13e between the bent portions 13c and the connection portions 13a and 13b, even if the batteries 11 and 11 are arranged vertically. No new bends or curves are created.
[0043]
Therefore, since the bent portion 13c of the tab 13 does not protrude outward from the outer edges 11e of the batteries 11, 11, the space occupied by anything other than the batteries 11, 11 in the case body 10 can be reduced. it can. Further, after the batteries 11, 11 are vertically arranged, as shown by arrows M and N in FIG. 10, by applying a force in a direction in which the batteries 11, 11 approach each other, the bent portion of the bent portion 13c of the tab 13 is bent. It is further bent so that the distance between the end face 11a of one battery 11 and the end face 11b of the other battery 11 is made as small as possible, and the space occupied by anything other than the batteries 11 in the case body 10. Can also be reduced.
[0044]
As shown in FIG. 5, in the case body 10 of the battery pack 1A, in addition to the batteries 11, 11, printed wiring boards 14a, 14b, 14c, a connector 15, and a PTC (Positive Temperature Coefficient: not shown). ) Etc. are arranged. The sheet-like switch 16, LEDs (light-emitting diodes) 17, 17, 17,... Are arranged on the printed wiring board 14c.
[0045]
By the way, it is desirable to use a lightweight lithium ion secondary battery having a high energy density for the batteries 11, 11,...
[0046]
However, when a lithium ion secondary battery is overcharged in excess of a predetermined battery voltage, deposition of lithium metal on a negative electrode, decomposition of a positive electrode active material, decomposition of an organic electrolyte, and the like generally occur, and a short circuit between the positive and negative electrodes occurs. , And the battery performance deteriorates. Conversely, when the lithium ion secondary battery is overdischarged below a predetermined battery voltage, the metal of the negative electrode current collector is ionized and eluted into the organic electrolyte, and the capacity due to the deterioration of the current collection function and the falling off of the negative electrode active material A drop occurs.
[0047]
Therefore, in the battery pack 1A, appropriate protection circuits are mounted on the printed wiring boards 14a and 14b in order to prevent the batteries 11 and 11 from being overcharged and overdischarged.
[0048]
The sheet-like switch 16 and the LEDs 17, 17,... Arranged on the printed wiring board 14c indicate the remaining amount of the batteries 11, 11, and are operated by operating the sheet-like switch 16. 17,... Light up to indicate the remaining battery level.
[0049]
The batteries 11, 11,... Are connected in a predetermined connection relationship by connection members 12a to 12h and tabs 13, 13, 13, as schematically shown in FIG. H, I and J are appropriately connected to the printed wiring board 14a or 14b at four places. The printed wiring boards 14a and 14c are connected by a flat cable 18. In addition, an insulating plate (not shown) is appropriately disposed in the case body 10 where insulation is required.
[0050]
It should be noted that the specific shapes and structures of the respective parts shown in the above-described embodiments are merely examples of the specifics performed when carrying out the present invention, and the technical scope of the present invention is thereby reduced. It should not be interpreted restrictively.
[0051]
【The invention's effect】
As is clear from the above description, the battery pack of the present invention accommodates a plurality of batteries in a case body, and electrodes of the batteries are electrically connected to each other by a connection member formed of a metal plate. In the battery pack, the connection member is formed in a band shape with a metal plate, and has a bent portion or a curved portion that protrudes in advance on one surface side in an intermediate portion, and the two connection members of the two batteries in the case body by the connection member. The invention is characterized in that the connection members are prevented from protruding outside the outer edge of the battery by connecting the electrodes located opposite to each other.
[0052]
Therefore, in the battery pack of the present invention, the intermediate portion of the connection member that connects between the electrodes located opposite to each other in the case body does not protrude outward from the outer edge of the battery. Batteries can be efficiently arranged without any wasted space in the body, and a battery pack having the smallest external dimensions can be provided.
[0053]
According to the invention described in claim 2, the bent portion of the connection member has a V-shape or a shape in which a plurality of V-shapes are continuous, so that the space between the electrodes located opposite each other in the two batteries in the case body. It is possible to effectively prevent the intermediate portion of the connection member to be connected from protruding outward from the outer edge of the battery.
[0054]
According to the third aspect of the present invention, since the battery electrode and the connection member are joined by welding, the connection strength between the battery electrode and the connection member can be increased.
[0055]
According to the invention described in claim 4, since the battery is a lithium ion secondary battery, the battery pack has characteristics such as high voltage, high energy density, and light weight suitable for use in portable electronic devices. It can be.
[Brief description of the drawings]
FIG. 1 shows a first embodiment of the battery pack of the present invention together with FIGS. 2 and 3, and FIG. 1 is a plan view schematically showing the appearance of the battery pack.
FIG. 2 is a perspective view of a connection member.
FIG. 3 is a perspective view showing a state in which after connecting the batteries by a connecting member, the connecting member is bent to arrange the battery vertically in order to arrange the battery inside the case body.
FIG. 4 shows a second embodiment of the battery pack of the present invention together with FIGS. 5 to 10, and is a perspective view schematically showing the appearance of the battery pack.
FIG. 5 is an exploded perspective view of the battery pack.
FIG. 6 is a diagram schematically showing an electrical connection state of batteries inside a battery pack.
FIG. 7 is a perspective view of a connection member.
FIG. 8 is a perspective view showing a state in which two batteries are arranged in parallel with the surfaces on which electrodes are not formed facing each other, and adjacent electrodes are connected to each other by a connection member.
FIG. 9 is a plan view schematically showing a state in which two batteries are arranged in parallel with the surfaces on which electrodes are not formed facing each other, and adjacent electrodes are connected to each other by a connection member.
FIG. 10 is a plan view schematically showing a state in which two batteries are rotated vertically by 90 ° from the state shown in FIG. 9 and arranged vertically.
11 shows a conventional battery pack together with FIGS. 12 and 13, and FIG. 11 is a plan view schematically showing an external appearance.
FIG. 12 is a perspective view showing a state where two batteries are arranged in parallel and electrodes are connected to each other by a connection member.
FIG. 13 is a perspective view showing a state in which after connecting the batteries by the connection members, the connection members are bent to arrange the batteries vertically in order to arrange them in the case body.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Battery pack, 2 ... Case body, 3 ... Battery, 3c ... Electrode, 3d ... Electrode, 4 ... Connection member, 4c ... Bending part, 1A ... Battery pack, 10 case body, 11 battery, 11c electrode, 11d electrode, 13 connecting member, 13c bending part

Claims (4)

A battery pack in which a plurality of batteries are housed in a case body, and electrodes of the batteries are electrically connected to each other by a connection member formed of a metal plate,
The connection member is formed in a strip shape with a metal plate and has a bent portion or a curved portion that is previously protruded to one surface side in an intermediate portion,
A battery pack characterized in that the connection member connects two electrodes located opposite to each other in the case body so that the connection member does not protrude outside the outer edge of the battery. The battery pack according to claim 1, wherein the bent portion of the connection member has a V shape or a shape in which a plurality of V shapes are connected. The battery pack according to claim 1, wherein the electrode of the battery and the connection member are joined by welding. The battery pack according to claim 1, wherein the battery is a lithium ion secondary battery.

Images