JP2002042774A - Battery excellent in safety - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery capable of efficiently discharging gas when internal pressure suddenly rises. SOLUTION: This battery 1 is provided with a battery element 2 including positive and negative electrodes 2a, 2b, a case 3 for housing the battery element 2, an electrode terminal 4 insulated from the case 3 and penetrating the case 3, and a safety valve 5 provided on the case 3. One of the positive and negative electrodes 2a, 2b is connected to the electrode terminal 4, and the other one is connected to the case 3 through collecting washers 6, 7. The collecting washers 6, 7 are fixed in the positions so as not to be overlapped on the safety valve 5 when the flat surface including the opening surface of the safety valve 5 is seen through.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a battery having excellent safety.

[0002]

2. Description of the Related Art Small electronic devices such as portable radio telephones, portable personal computers, and portable video cameras have become widespread. As a battery built in these electronic devices, a non-aqueous secondary battery has been used in many cases. FIG. 2 shows a perspective view of a conventional non-aqueous secondary battery, and FIG. 3 shows its internal structure.

The battery 11 has a positive electrode plate 12a and a negative electrode plate 1a.
2b and a storage element 12 including a separator 12c interposed therebetween and holding the non-aqueous electrolyte. The storage element 12 is housed in a rectangular case 13. Case 13
A negative terminal 14 is provided at the center of the cover 13a so as to penetrate the same, and a negative electrode plate 12b is connected to the negative terminal 14 via a negative current collecting washer 17. The positive electrode plate 12a is connected to the lid 1 via a positive current collector washer 16.
3a. The negative electrode terminal 14 and the negative electrode current washer 17 are separated from the lid 13a by a packing 18 and insulated. Further, the battery 11 has a safety valve 1 for discharging gas when the internal pressure increases in order to prevent the internal pressure from rising due to the generation of gas and causing the battery 11 to burst.
5 is provided at the end of the lid 13a.

[0004]

However, this battery 11
Then, the back surface of the safety valve 15 is covered with the negative electrode current washer 17. Therefore, when the internal pressure rises sharply, the moving speed of the gas toward the safety valve 15 cannot keep up with the increasing speed of the internal pressure, and as a result, the battery 11 may burst. Therefore, an object of the present invention is to provide a battery that can efficiently discharge gas when the internal pressure rises sharply.

[0005]

A battery according to the present invention comprises: a power storage element including positive and negative electrodes; a case for housing the power storage element;
An electrode terminal penetrating the case while insulating from the case, and a safety valve provided on the case, wherein one of the positive and negative electrodes is connected to the electrode terminal, and the other is connected to the case via the current washer, respectively. When viewed through a plane including the opening surface of the safety valve, the current collecting washer is fixed at a position not overlapping with the safety valve.

[0006] In the battery of the present invention, when the plane including the opening surface of the safety valve is seen through, each current washer is fixed at a position that does not overlap with the safety valve. Therefore, when the internal pressure is rapidly increased, the gas moves quickly toward the safety valve without being hindered by the current collecting washer. Further, since the current collecting washer is fixed at a position not overlapping with the safety valve, it is possible to fix the end of the electrode connected to the current collecting washer so as not to overlap with the safety valve. In this way, the gas can be moved to the safety valve more quickly. Therefore, according to the present invention, gas can be efficiently exhausted when the internal pressure rises sharply, and battery rupture can be prevented. In order to prevent the ends of the electrodes from overlapping with the safety valve, for example, the power storage element is formed by spirally winding positive and negative electrodes via a separator, and collecting the outermost end of each electrode. It is preferable to form the same width as the washer, draw it out, and connect it to the current collecting washer.

The present invention can be suitably applied to a non-aqueous secondary battery. In this case, as the electricity storage element, for example, a positive electrode plate coated with an active material such as lithium cobalt oxide, a separator holding an organic electrolyte containing a lithium salt, and a negative electrode plate coated with a host material such as carbon Are sequentially laminated and spirally wound. As the case, a square case can be used. In order to insulate the case from the electrode terminal passing therethrough, it is preferable to separate the electrode terminal from the case by packing made of an insulating material. In addition, it is preferable that the current collecting washer connected to the electrode terminal is separated from the case by packing. In order to connect the current washer and the electrode, it is advisable to insert a needle into a portion where the current washer and the electrode are overlapped and swage them. Furthermore, in order to provide a safety valve on the lid of the case, for example, it is preferable to perform press molding or clad material joining.

[0008]

FIG. 1 is a diagram showing the internal structure of a battery according to an embodiment. Power storage element 2 of battery 1 of the present embodiment
Is a positive electrode plate 2a coated with lithium cobalt oxide, Li
A separator 2c made of polypropylene holding an organic electrolyte containing PF ₆ and a negative electrode plate 2 coated with carbon
b are sequentially laminated and spirally wound so that the positive electrode plate 2a becomes the outermost layer.

The power storage element 2 is housed in a rectangular case 3. A negative electrode terminal 4 is provided at the center of the lid 3a of the case 3 so as to pass therethrough, and a safety valve 5 is provided at an end. A positive electrode current collector washer 6 is connected to an end of the inner surface of the lid opposite to the safety valve 5. Further, between this and the safety valve 5, there is a negative current collector washer 7, and a negative terminal 4
Is connected to At the ends of the positive electrode plate 2a and the negative electrode plate 2b,
A part thereof is formed to have the same width as the positive electrode current washer 6 and the negative electrode current washer 7, respectively, and extends toward the lid 3a. In this portion, the electrode plates 2a and 2b are connected to the current collecting washers 6 and 7 by needle caulking. Incidentally, the negative electrode terminal 4 and the negative electrode current washer 7 are separated from each other by the packing 8 and insulated from the lid 3a, so that there is no short circuit. Furthermore, since the separator 2c is wider than the negative electrode plate 2b, the negative electrode plate 2b does not contact the side wall of the case 3 to cause a short circuit.

In a non-aqueous secondary battery such as the battery 1,
When the battery is placed at a high temperature or charged with an excessive current, a gas such as carbon dioxide is easily generated from the electrolyte. When gas is generated, the internal pressure of the battery 1 increases. Here, in the battery 1 of the present embodiment, the safety valve 5 is provided on the lid 3 a of the case 3, and the ends of the current collecting washers 6 and 7 and the electrode plates 2 a and 2 b do not overlap with the safety valve 5. Fixed. Further, since the separator 2c is melted by the high temperature, a gas passage is formed along the side wall of the case 3. Therefore, in this embodiment, when the internal pressure rises sharply, the gas moves to the safety valve 5 quickly and is discharged efficiently. Therefore, the battery 1 of the present embodiment does not burst even when the internal pressure rises sharply, and has high safety.

[0011]

According to the battery of the present invention, when the internal pressure rises rapidly due to the generation of gas, the gas can be efficiently discharged. Therefore, the battery of the present invention is safe without rupture.

[Brief description of the drawings]

FIG. 1 is a diagram showing an internal structure of a battery according to an embodiment.

FIG. 2 is a perspective view showing a conventional battery.

FIG. 3 is a diagram showing the internal structure of a conventional battery.

[Explanation of symbols]

 1 Battery 2 Storage element 2a Positive electrode plate 2b Negative electrode plate 2c Separator 3 Case 4 Negative terminal 5 Safety valve 6 Positive current collecting washer 7 Negative current collecting washer 8 Packing

Continued on front page F-term (reference) 5H012 AA01 BB02 CC01 GG01 JJ01 5H022 AA09 AA18 BB03 CC03 CC08 CC12 CC19 CC21 5H029 AJ12 AK03 AL06 AM02 AM07 BJ02 BJ14 BJ27 CJ05 CJ07 DJ05 HJ04 HJ12

Claims (2)

[Claims] An electric storage element including positive and negative electrodes, a case for housing the electric storage element, an electrode terminal penetrating through the case while being insulated from the case, and a safety valve provided in the case,
In batteries where one of the positive and negative electrodes is connected to the electrode terminal and the other to the case via a current collector washer, the current collector washer is fixed at a position where it does not overlap the safety valve when seen through the plane including the opening of the safety valve. A battery characterized in that: 2. The power storage element according to claim 1, wherein a positive electrode and a negative electrode are spirally wound via a separator, and the outermost end portion is formed to have the same width as the current collecting washer, is drawn out, and is connected to the current collecting washer. The battery according to claim 1.