JPH11345600A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently arrange lithium ion batteries and electronic components while maintaining a compact form. SOLUTION: Set batteries are arranged in the form of L inside a battery pack in such 11 way that the axes ofthe batteries 13-16 cross. A circuit board 17 of the size matching a rectangular contour comprised of the length and width of the set batteries is built into the battery pack. Electronic components 26a constituting a charge-discharge control circuit are mounted in the spaces of the circuit board 17 which are left behind after installation of the batteries 13-16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chargeable / dischargeable battery pack used for portable electronic equipment, for example, a portable telephone, a notebook computer, a camcorder, a CD player, and the like.

[0002]

2. Description of the Related Art A battery pack contains a plurality of secondary batteries connected in series or in parallel.
In recent years, battery packs as well as electronic devices have been reduced in weight and size, and accordingly, batteries have been arranged closely or vertically to save space. In addition, as a secondary battery, the operating voltage is high, the energy density is high, the discharge voltage is high, the cycle life is long, there is no memory effect, it is possible to charge in a short time, etc. Lithium-ion batteries are frequently used.

When a lithium-ion battery is short-circuited, it generates heat and may explode or ignite. In addition, when the battery is charged with an overcurrent, the battery temperature rises abnormally and the battery life is shortened. Further, inconvenience is caused by overcharge, overdischarge, and the like. In order to prevent such inconvenience, a charge / discharge control circuit is provided in a battery pack using a lithium ion battery. The charge / discharge control circuit includes a monitoring circuit that monitors battery temperature, battery current, battery voltage, and the like, and a switching circuit that is turned ON / OFF by the monitoring circuit to stop charging or discharging.

As described in Japanese Patent Application Laid-Open No. 4-331425, a conventional battery pack includes a circuit board provided with a charge / discharge control circuit and the like, and a plurality of lithium ion batteries mounted on the circuit board. And a case for accommodating them. One end of an L-shaped connection terminal is soldered to the circuit board, and a lithium ion battery is spot-welded to the other end. Each lithium ion battery is fixed on the circuit board by the connection terminal.

[0005]

In the above-mentioned conventional battery pack, each electronic component constituting the charge / discharge control circuit is mounted on a circuit board so as to enter a gap between two lithium-ion batteries arranged side by side. Installed. In recent years, the number of items for monitoring the state of lithium ion batteries has increased, and communication with electronic devices has complicated the configuration of the charge / discharge control circuit and the number of electronic components has increased considerably. ing. For this reason, when the size of the circuit board is substantially the same as the size when the lithium ion batteries are arranged side by side, there is a problem that a space for disposing the electronic components cannot be secured.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a battery pack that can secure a space for storing electronic components while maintaining a compact form.

[0007]

According to a first aspect of the present invention, there is provided a battery pack, which has a rectangular shape having a short side and a long side, and controls charging and discharging of a secondary battery. A circuit board on which a discharge control circuit is mounted and housed in a case: at least two or more of the secondary batteries are arranged side by side, and one side in a longitudinal direction of a rectangle forming an outline thereof is set as a short side of the board; And a first assembled battery disposed on the substrate such that the other side along the diametric direction is along the long side of the substrate, and at least two or more secondary batteries are arranged side by side, and A second assembled battery disposed on the substrate in a direction intersecting with the first assembled battery and having one longitudinal side of the rectangle forming the battery contour along the long side of the substrate And the short side of the substrate is
At least the length of one side in the longitudinal direction of the first assembled battery is equal to or slightly larger than the length of the substrate, and the long side of the substrate is at least the longitudinal length of the first assembled battery and the diametrical direction of the second assembled battery. Electronic components constituting at least a part of the charge / discharge control circuit in the remaining rectangular space in which the first and second battery packs are arranged, the length being equal to or slightly larger than the sum of the lengths. It is.

[0008] In the battery pack according to the second aspect, the first battery pack extends vertically from the inner surface of the case.
And at least one second reinforcing rib extending in a second direction orthogonal to the first direction, wherein each reinforcing rib has a concave shape. The receiving portion is provided by the number of batteries constituting the assembled battery, and when the assembled battery is housed in the case together with the circuit board, each battery fits into the receiving portion.

According to a third aspect of the present invention, there is provided a battery pack, wherein a partition wall protruding vertically from the inner surface of the case and entering between the horizontally arranged secondary batteries and partitioning the inside of the case is provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a battery pack 10 has lithium ion batteries 13 to 1 in a rectangular case composed of a case lid 11 and a case body 12.
6 and a charge / discharge control circuit are mounted on a circuit board 17 to integrate a battery unit 18 therein.

The circuit board 17 is formed in a rectangular shape large enough to be inserted into the rectangular space of the case body 12. The circuit board 17 is provided with a connector 20 that is exposed to the outside through an opening 19 provided in the case body 12. The connector 20 has a positive terminal, a negative terminal,
And a connection detection terminal. The plus terminal and the minus terminal are terminals for charging and discharging between an electronic device and a charger. Each of the lithium ion batteries 13 to 16 has a columnar shape with the same dimensions, and its electrodes are spot-welded to the battery connecting plate 21. This battery connection plate 21
Are fixed to the circuit board 17 by soldering to the pattern of the circuit board 17.

As shown in FIG. 2, the circuit board 17 has a rectangular shape having a short side a and a long side b. The length of the short side a is a length B slightly larger than the length A of one battery in the longitudinal direction (axial direction). The long side b has a length D slightly larger than the sum of the length C and the length A along the diameter direction of two batteries. The length of the short side a may be the same as the length A, and the length of the long side b may be the same as the length D.

The four batteries 13 to 16 are the first battery pack 2
2 and a second assembled battery 23. The first assembled battery 22 is composed of two secondary batteries 13 and 14 arranged side by side, and the axial direction of each of the secondary batteries 13 and 14 is
Are arranged on the circuit board 17 so as to be parallel to the short side a.

The second assembled battery 23 is composed of two rechargeable batteries 15 and 16 arranged side by side, and is disposed on the circuit board 17 so that its axial direction is parallel to the long side b. I have.

On the circuit board 17, a first assembled battery 22 and a second assembled battery 23 are arranged in an L-shape so as to be orthogonal to each other, and as shown in FIG. An electronic component 26a constituting the charge / discharge control circuit 26 is mounted.

In order to secure the empty space 25,
Two assembled batteries 22 and 23 in which two batteries are arranged in parallel are arranged so as to cross each other so as to be substantially L-shaped, and the size of the circuit board 17 is determined according to a rectangle formed by the vertical and horizontal sides thereof. Therefore, as the secondary batteries 13 to 16 to be used,
It is necessary that the axial length of the battery is larger than twice the diameter of the battery. As a battery that meets this condition,
17 mm in diameter, 67 mm in axial length, and 1 mm in diameter
8mm, 65mm in axial length, 17m in diameter
m, the longitudinal length is 50 mm, and the diameter is 18
mm and a length in the longitudinal direction of 50 mm. These batteries have an aspect ratio of 2.77 to 3.9 in the plane.
It becomes 5.

In FIG. 4, the charge / discharge control circuit 26 includes:
A monitoring circuit and a switching circuit 31 are provided. The switching circuit 31 includes a charge stop FET (field effect transistor) 32 and a discharge stop FET 33. The charge stop FET 32 is turned off when the lithium ion batteries 13 to 16 reach the charge stop voltage to stop charging. The discharge stop FET 33 is turned on when the lithium ion batteries 13 to 16 decrease to the discharge stop voltage.
The discharge is stopped by FF.

The monitoring circuit comprises a measuring section and a judging section for judging an abnormality based on a signal from the measuring section and turning on / off the switching circuit 31 if it judges that an abnormality has occurred. As the determination unit, for example, the microcomputer 34 is used. The measuring unit includes a current measuring circuit 35 for measuring the current of the lithium ion batteries 13 to 16, the lithium ion battery 1
It comprises a voltage measuring circuit 36 for measuring voltages of 3 to 16 and a temperature measuring circuit 37 for measuring heat generation temperatures of the lithium ion batteries 13 to 16.

The voltage measuring section 36 is connected to both ends of the four lithium ion batteries 13 to 16 and measures these voltages. The current measuring unit 35 is connected between the negative electrode of the lithium ion battery 16 and the negative terminal 38, and measures a current flowing through the resistor 39 having a known resistance value. The temperature measurement circuit 37 uses, for example, an NTC type thermistor or the like, and measures the battery temperature by utilizing the property that the resistance value decreases in proportion to the temperature.

The microcomputer 34 determines a battery abnormality such as a short circuit, an overcurrent, an overcharge, and an overdischarge based on the information obtained from the measuring unit described above, and controls the switching circuit 31 to stop the charging and discharging. . When it is determined that the electronic device is not connected through the connection detection terminal 40, the switching circuit 31 is turned off. Accordingly, even when the plus terminal 41 and the minus terminal 38 come into contact with each other when the battery pack 10 is not connected to an electronic device or a charger, a short circuit does not occur.

The circuit board 17 is inserted into the rectangular case body 12 with the batteries 13 to 16 facing downward. The case body 12 is formed of an insulating plastic material, and has reinforcing ribs 42a to 42d for preventing flat warpage and reinforcing strength. As shown in FIGS. 1, 5, and 6, the reinforcing ribs 42 a to 42 d are formed with an arc-shaped receiving portion 43 that receives a part of the outer periphery of each of the batteries 13 to 16 from below. Note that the shape of the receiving portion 43 may be V-shaped or rectangular.

The pair of reinforcing ribs 42a and 42b are
The battery is provided so as to extend in the diameter direction of the battery so as to receive two locations on both ends in the axial direction of the batteries 3 and 14. These reinforcing ribs 42
The receiving portions 43 of a and 42b hold the batteries 13 and 14 so as not to come into contact with the inner surface of the case main body 12, thereby absorbing shocks due to dropping and vibrations during transportation so as not to be directly applied to the batteries 13 and 14. I do. The receiving portions 43 are provided at predetermined intervals so that the batteries do not come into close contact with each other.
When one battery generates heat, heat is prevented from being transmitted to the other battery. The reinforcing ribs 42c and 42d for holding the batteries 15 and 16 have the same structure.

The edge of one end of the case body 12 is in contact with one edge of each of the batteries 13 to 16 on both pole sides, so that each of the batteries 13 to 1
Reinforcing ribs 44 are also formed to restrict the 6 from moving in the longitudinal direction. Reference numeral 45 denotes a partition wall, and the battery 1
3 and the battery 14 so as to keep them from moving and partition the case body 12. This partition wall 45 prevents the electrolyte solution from adhering to the circuit board 17 and causing a short circuit, even if the battery 13 leaks, even if the battery 13 leaks. doing.

As shown in FIG. 5 and FIG.
1, the reinforcing ribs 46 are also provided in a lattice shape. The reinforcing rib 46 presses the circuit board 17 from above toward the case body 12 on the distal end side. The case lid 11 has a recess 47 formed on a part of the inner wall thereof. The recess 47 receives lead terminals of electronic components protruding from the back surface of the circuit board 17 to reduce the thickness of the case itself. Is being planned.

Next, the operation of the above embodiment will be described. When assembling the battery pack 10, the circuit board 1
A part of the electronic components constituting the charge / discharge control circuit 26 is mounted in the rectangular space 25 of FIG. Also, the small electronic components are arranged in the space between the two batteries. Next, the battery connection plate 21 is soldered to the circuit board 17. Between a pair of battery connection plates 21, lithium ion batteries 13, 1
Insert 4. Thereafter, the battery connecting plate 21 is spot-welded to the electrode of the lithium ion battery. The assembled circuit board 17 is inserted into the case main body 12 with the batteries 13 to 16 facing downward, and the battery pack 10 is completed by fitting the case lid 11 from above. Since the case lid 11 is coated with an adhesive, it is fixed to the case body 12.

In this state, the lithium ion batteries 13 to
The batteries 16 enter the respective receiving portions 43 of the reinforcing ribs 42 and are held apart from the inner wall, and the batteries 13 to 16 of each set are held apart. Since the receiving portion 43 has an arc shape, the movement in the diameter direction of the battery is reliably prevented, and the movement of the batteries 13 to 16 in the longitudinal direction is also prevented by the reinforcing rib 44. 13 to 16 are fixed so as not to move. Thus, even if the battery pack 10 is vibrated, the spot welding between the batteries 13 to 16 and the battery connecting plate 21 and the soldering of the circuit board 17 do not come off.

In the above embodiment, the four batteries 13 to 16 are of a type connected in series, but a type of two batteries connected in parallel may be connected in series.

Although four batteries are used in the above embodiment, four or more batteries may be used in the present invention. FIG.
This is an example in which six batteries 50 to 55 are used. Also in this case, each of the batteries 50 to 55 has a shape in which the length H in the axial direction is longer than the length G which is three times the diameter. Used. By using a battery of this size and mounting a set of three batteries in a direction in which the axial directions intersect with each other, the circuit board 56
A rectangular space 57 for mounting the charge / discharge control circuit 26 is formed at one of the four corners. Therefore,
The circuit board 56 of this example has a short side h equal to or slightly longer than the length H of one of the batteries 50 to 55 along the axial direction, and a diametric length of three batteries. The rectangle has a long side k which is the same as the length obtained by adding G and the length H in the axial direction, or is slightly longer than this.

As a connection method when using six batteries 50 to 55, as shown in FIG. 8, two assembled batteries connected in parallel may be connected in series, or as shown in FIG. Alternatively, three battery packs connected in parallel may be connected in series. In the case of the example shown in FIG. 9, if the polarity of the batteries is aligned in each assembled battery and they are arranged side by side, it is only necessary to connect to one horizontally long battery connection plate, so that the arrangement of the battery connection plates is simplified. . In this case, as shown in FIG. 10, when each of the batteries 50 to 55 having the narrowed portion 60 formed near the positive pole is used, the mounting direction of the batteries can be easily inspected.

The charge / discharge control circuit 26 includes a thermistor, a plastic switch, and a temperature fuse for detecting the temperature inside the pack. If these temperature sensors are mounted in contact with the circuit board 17, temperature detection may not be performed correctly. Therefore, it is preferable to provide an opening in the circuit board 17 and arrange the temperature sensor therein. In this case, most of the temperature sensors are mounted on the circuit board 17.
And the case lid 11 are not contacted.

In the above embodiment, a lithium ion battery is used as a secondary battery, but a nickel cadmium battery or the like may be used.
Furthermore, the number of secondary batteries is not limited to four or six, but may be four or more.
Any number is acceptable.

[0032]

As described above, the battery pack of the present invention has a rectangular circuit formed by arranging two sets of batteries in which a plurality of batteries are arranged side by side so that the longitudinal directions of the batteries intersect. Since it is arranged on the board and the electronic parts that constitute a part of the charge and discharge control circuit are mounted in the remaining empty space, while maintaining the conventional compact form,
A storage space for electronic components can be reliably secured.

According to the second aspect of the present invention, the receiving portions are formed on the reinforcing ribs formed on the case, and the batteries are fitted into these receiving portions.
Inconveniences such as cracks in soldering and breakage of the case can be reliably prevented. Further, the contact between the batteries can be reliably prevented, and the cost is low as compared with a type in which a spacer or insulating paper is separately provided between the batteries.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a battery pack according to the present invention.

FIG. 2 is a plan view of a battery unit.

FIG. 3 is a perspective view of a battery unit.

FIG. 4 is a circuit diagram of a charge / discharge control circuit.

FIG. 5 is a vertical sectional view of the battery pack.

FIG. 6 is a cross-sectional view of the battery pack.

FIG. 7 is a plan view of an example of a battery unit using six batteries.

FIG. 8 is a connection diagram of six batteries.

FIG. 9 is another connection diagram of six batteries.

FIG. 10 is a perspective view showing a battery in which a throttle portion is formed on the positive electrode side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Battery pack 13-16, 50-55 Lithium ion battery 17 Circuit board 26 Charge / discharge control circuit 42,44 Reinforcement rib 43 Receiving part

Claims (3)

[Claims] 1. A battery pack in which at least four or more cylindrical secondary batteries are incorporated in a case, wherein the battery pack has a rectangular shape having a short side and a long side, and controls charging and discharging of the secondary battery. A control circuit is mounted, a circuit board housed in the case, and at least two or more of the secondary batteries are arranged side by side, and one side in a longitudinal direction of a rectangle forming an outline thereof is a short side of the board, A first side disposed on the substrate such that the other side along the diametrical direction is along the long side of the substrate.
And at least two or more of the secondary batteries are arranged side by side,
And a second assembled battery disposed on the substrate so that one side in the longitudinal direction of the rectangle forming the battery contour is along the long side of the substrate. The short side of the substrate is at least as long as or slightly longer than one side of the first assembled battery in the longitudinal direction, and the long side of the substrate is at least the longitudinal length of the first assembled battery. At least a part of the charge / discharge control circuit is provided in the remaining rectangular space in which the first and second assembled batteries are arranged, the length being equal to or slightly larger than the length obtained by adding the length in the diameter direction of the second assembled battery. A battery pack characterized by mounting electronic components constituting the same. 2. At least one first reinforcement rib extending in a first direction and vertically extending from an inner surface of the case, and at least one first reinforcement rib extending in a second direction orthogonal to the first direction. One second reinforcing rib is provided, and each reinforcing rib is provided with concave receiving portions by the number of batteries constituting the assembled battery, and when the assembled battery is housed in the case together with the circuit board,
2. The battery pack according to claim 1, wherein each battery is fitted in a receiving portion. 3. The battery according to claim 1, further comprising a partition wall protruding vertically from an inner surface of the case, entering between secondary batteries arranged side by side, and partitioning the inside of the case. pack.