JPH1050281A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance safety in the constitution of unit cells and a temperature sensitive element of a battery pack used in small portable communication devices and notebook type personal computers. SOLUTION: Unit cells 2 are connected with connecting plates 3, 4, 5, 6, 7 in parallel of two parts of four in series by resistance welding to constitute a battery block, some temperature sensitive element 8 is connected to one end of the connecting plate 5 on the plus side of the battery block by soldering, or some temperature sensitive elements 8 are connected in series with connecting plates 10, 11, 12 by resistance welding. These temperature sensitive elements 8 are arranged so as to come in contact with the surfaces of the unit cells 2 of a parallel connecting block of the battery block, a terminal 13 and a safety protecting circuit board 14 are fixed to the battery block, then they are housed in an outer jacket resin case 1. A battery pack with high safety in which the temperature sensitive element 8 quickly detects abnormal heat generation caused by overcharging of the unit cells 2 and shuts off the circuit is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack containing a temperature sensing element for ensuring safety during overcharge or abnormal heat generation.

[0002]

2. Description of the Related Art In recent years, due to the increasing functionality of small portable communication devices and notebook personal computers, battery packs serving as driving power sources have been required to have higher energy in order to cope with the increased functionality. Lighter and more lightweight are required.

However, in recent battery packs, an electronic circuit, a protection element, and the like are often mounted in the battery pack for reasons of safety or charge / discharge current drive power supply control. Especially in the back of a lithium ion secondary battery,
Normally, when a series-parallel configuration is used, blocks in which unit cells are connected in parallel are further connected in series, and the voltage of each block is monitored.
Two temperature sensing elements are installed on or near a specific battery block, particularly on the surface of a unit cell which is susceptible to heat of the main unit.

[0004]

However, in a conventional large battery pack using a large number of batteries, when there is no temperature sensing element on or near the surface of the unit cell that has generated heat, an abnormality cannot be quickly detected, so that ignition occurs. There was a problem that could lead to.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a battery pack with improved safety.

[0006]

In order to achieve the above object, a battery pack according to the present invention is a battery pack comprising a plurality of unit cells connected in parallel, and a plurality of sets of blocks connected in parallel connected in series. A plurality of temperature sensing elements are installed in a series circuit in a battery pack, and each of the plurality of temperature sensing elements is arranged on or near a unit cell in the block.

With the above-described structure, the battery pack according to the present invention can detect abnormal heat generation due to overcharging or short circuit of the cells or abnormal heat generation in a high-temperature atmosphere for each cell, thereby improving the sensitivity of abnormality detection. When the abnormal heat generation of the unit cell occurs, the temperature sensing element operates quickly to cut off the circuit of the battery pack, thereby preventing ignition and explosion and ensuring safety.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, in a battery pack in which a plurality of unit cells are connected in parallel and a plurality of unit cells are connected in series, a plurality of temperature sensing elements are connected in series in the battery pack. The plurality of temperature sensing elements are installed in a circuit, and each of the plurality of temperature sensing elements can be implemented by being disposed on or near the surface of a unit cell in a separate block. As the temperature sensing element, a temperature fuse that does not return after being blown or a return type thermostat can be used.

Further, as the temperature sensing element, the above-mentioned non-return type temperature sensing element and return type temperature sensing element can be mixed.

The present invention can be carried out in the above-described embodiment, and a highly safe battery pack can be realized.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an exterior resin case of a battery pack, which is formed of, for example, polycarbonate so as to house a battery block, a safety protection circuit, and terminals. Reference numeral 2 denotes a unit cell. For example, lithium cobalt oxide is used for a positive electrode, carbon is used for a negative electrode, and an electrode plate group separated by a separator is housed in a cylindrical metal case.
This is a cylindrical lithium ion secondary battery in which an electrolyte is injected and sealed.

The above-mentioned lithium ion secondary battery is constructed by two parallel 4 using nickel connection plates 3, 4, 5, 6 and 7.
The battery blocks are connected by using resistance welding so as to be in series. Numeral 8 denotes a temperature-sensitive element, for example, using a non-return type thermal fuse. Is connected to the connection plate 9. Some are connected using resistance welding so that the temperature-sensitive elements 8 are connected in series using connection plates 10, 11, and 12 made of nickel. Is connected to one end of the side connection plate 7 by using soldering. Further, these temperature sensing elements 8 are arranged so as to be connected to the surface of the unit cell of the parallel connection block of the aforementioned battery block.

Reference numeral 13 denotes a terminal for the present battery pack, which is soldered to a security protection circuit board 14, and a thermistor 16 to which a lead wire 15 is attached is further attached to the security protection circuit board 14 by soldering. I have. The safety protection circuit board 14 is provided with the above-described temperature sensing element 8.
Are connected to the connection plates 9 and 12 of the battery block to which solder is attached by using solder, and a lead wire 17 for confirming the intermediate voltage is connected from the serially connected portion of the battery block.

The battery block and the safety protection circuit board 14 formed as described above are housed in the above-mentioned exterior resin case 1 and bonded.

In the battery pack of the present invention, a non-return type temperature fuse is used as the temperature sensing element 8 for interrupting the circuit. There is no. In particular, for normal use, by incorporating a return-type thermostat or PTC in a place where the main body is likely to receive heat, it is possible to prevent unintentional interruption of the non-return circuit. Also, there is no problem if the composition ratio of the non-return type and the return type temperature sensing element is changed in any manner.

[0017]

As described above, according to the present invention, since at least one temperature sensing element built in a battery pack is arranged in each parallel connection block in a series-parallel configuration, abnormal heat generation of a unit cell can be quickly performed. It is possible to sense and improve safety and reliability.

[Brief description of the drawings]

FIG. 1 is a perspective view of a battery pack of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer resin case 2 Unit cell 3, 4, 5, 6, 7, 9, 10, 11, 12 Connection plate 8 Temperature sensitive element 13 Terminal 14 Safety protection circuit board 15, 17 Lead wire 16 Thermistor

Claims (3)

[Claims] 1. A battery pack in which a plurality of unit cells are connected in parallel to each other and a plurality of temperature sensing elements are arranged in a series circuit in the battery pack, wherein the plurality of temperature sensing elements are connected in series. Battery packs each disposed on or near the surface of a unit cell in a separate block. 2. The battery pack according to claim 1, wherein all of the plurality of temperature sensing elements are non-return type temperature sensing elements. 3. The battery pack according to claim 1, wherein the plurality of temperature sensing elements include both a non-return type temperature sensing element and a return type temperature sensing element.