KR100381328B1 - Li-ION BATTERY USING SIMPLIFIED SAFETY VENT - Google Patents

Abstract

In the case of a lithium ion battery using a nonaqueous electrolyte, there is a risk of misuse such as overcharge or explosion due to manufacturing defects. In order to prepare for such a case, when the pressure inside the battery rises, a safety plate that cuts off the current and releases the internal pressure at the same time is installed in the upper part of the battery cap. In the present invention, the inner gasket of the safety plate is removed and used. By making the lower safety plate enclosing the cap part as a whole, the gasket is made integrally to shorten the assembly process on the assembly line, reduce the number of parts, and reduce the corresponding process cost and part price, and also By reducing the thickness and moving the bead height of the can into which the jelly roll is inserted into the upper part of the battery, a structure for increasing the battery capacity by securing the internal space of the battery and increasing the width of the electrode was proposed.

Description

Li-ion battery using integrated safety plate {Li-ION BATTERY USING SIMPLIFIED SAFETY VENT}

The present invention relates to a lithium ion battery having an integrated safety plate. In particular, the present invention relates to a lithium ion battery having a safety plate that separates the upper and lower safety plates to block the flow of current when there is an increase in the internal pressure of the battery due to battery misuse.

In addition to the rapid spread of portable electronic devices, the use of lithium ion batteries has also been rapidly expanded. However, due to the high energy of lithium ion batteries and the dendrite phenomenon of lithium metal on the negative electrode surface, there is a possibility of explosion of the battery due to misuse. To eliminate this problem, each battery manufacturer employs a unique safety plate for the battery.

In the safety plate of the conventional cylindrical lithium-ion battery, at least six components form the upper structure of the cylindrical battery by arranging the safety plate components in order from the top of the gasket.

1 is a cross-sectional view of a conventional safety plate applied to a cylindrical lithium ion battery. The conventional safety plate has a complicated structure, a complicated manufacturing process, and a large upper cap, thereby reducing the effective volume of the battery body.

As a result, the conventional structure has a burden on the efficient design of the battery because the structure is complicated and the volume of the battery is large in comparison with its function.

An object of the present invention is to provide a safety plate structure that can optimize the use of battery internal capacity by simplifying the structure and assembly process of the safety device while ensuring the stability of the battery.

The present invention relates to the use of a safety plate in order to ensure the safety of the lithium ion battery.

The safety plate is composed of an upper cap, a gasket, a positive temperature coefficient element, an upper safety plate, and a lower safety plate, and the lower safety plate is perforated so as not to be affected by the pressure increase when the pressure inside the battery increases. The center portion is arranged by ultrasonic welding at the upper portion, the gasket is not provided with an inner gasket between the upper safety plate and the lower safety plate, partly interposed with the upper cap, positive temperature coefficient, close to the outer periphery of the upper and lower safety plates The safety plate structure of the present invention does not use an internal gasket that has been used in the prior art.

In the operation of the safety plate, when the pressure inside the battery increases, the lower safety plate has a hole in itself and is not affected by pressure, while the upper safety plate rises upward due to the pressure, and the adhesive surface with the lower safety plate is shorted. The current is interrupted as a result of this short circuit.

The material of the upper safety plate and the lower safety plate of the safety plate of the present invention includes aluminum or an aluminum alloy, and the gasket is made of a polyolefin-based material.

By manufacturing the lower safety plate integrally with the lower part of the gasket, the thickness of the safety plate assembly portion can be reduced to increase the bead height of the can, thereby increasing the battery capacity by increasing the width of the electrode used in the battery body.

1 is a safety plate cross-sectional view of a conventional cylindrical lithium ion battery.

Figure 2 is a safety plate cross-sectional view of the cylindrical lithium ion battery according to the present invention.

<Explanation of symbols for main parts of drawing>

11, 22: gasket

12, 21: lower safety plate

13: internal gasket

14, 23: upper safety plate

15, 24: positive temperature coefficient element

16, 25: upper cap

The battery of the present invention is provided with a safety plate that separates the upper and lower safety plates to block the flow of current when there is an increase in the internal pressure of the battery due to battery abuse. In the present invention, in order to solve the problems of the prior art, the lower safety plate was placed under the gasket, and used a space remaining as an empty space in the conventional cylindrical battery, and thus, the safety plate could be used without using an internal gasket.

2 is a cross-sectional view of the safety plate of the battery to which the present invention is applied. In the safety plate of the battery to which the present invention is applied, by reducing the number of parts included in the upper structure, the weight and volume of the upper battery structure are reduced relative to the battery body, thereby increasing the electrode width of the battery body by approximately 0.5 mm to increase the battery capacity. It also reduced the process and component costs of component assembly.

Example

First, an aluminum plate having an outer diameter of 13.15 mm and a thickness of 0.4 to 0.5 mm with six small holes having a diameter of 2 mm rounded around the center is manufactured. Next, the manufactured plate is placed in a previously manufactured gasket mold and injection molded to manufacture a gasket having a lower safety plate and a gasket integrally.

After welding the anode terminal of the jelly roll to the lower safety plate thus manufactured, insert the upper safety plate into the lower safety plate and the gasket. At this time, the upper safety plate is the outer diameter of 16.0 ~ 16.1 mm, the thickness is 0.1 mm, and the groove is rolled to a size of about 6 mm diameter around the center. At this time, the grooved depth is 0.07 mm, and the aluminum thickness of the groove after rolling is 0.03 mm. After inserting the upper safety plate, use the ultrasonic welding machine to connect the upper and lower safety plates to the center of the upper and lower safety plates. In the next process, a positive temperature coefficient element for overcurrent protection is laminated in the event of overcurrent due to an abnormal electrode reaction, and the top cap is inserted and laminated in the final process.

The primary short circuit and the secondary upper safety valve venting pressures of the upper and lower safety valves are 8 to 10 kgf / cm 2 and 17 kgf / cm 2 ± 3 kgf / cm 2.

By applying the safety plate to which the present invention is applied to a lithium ion battery, the manufacturing process can be simplified, the weight and volume of the battery can be reduced to meet the miniaturization requirement, and the electrode width can be increased with the increase of the effective volume of the battery body. This increases.

Claims (4)

In the safety plate of the lithium ion battery, Upper cap; Positive temperature coefficient element; A lower safety plate which is perforated so as not to be affected by the pressure increase when the pressure inside the battery increases; An upper safety plate in which a center portion is ultrasonically welded to an upper portion of the lower safety plate; And a gasket disposed in close contact with the upper cap, the positive temperature coefficient, and the outer circumference of the upper and lower safety plates with a portion interposed without the inner gasket between the upper safety plate and the lower safety plate. The safety plate is a safety plate of a lithium ion battery, characterized in that to block the current when the internal pressure rise of the battery to prevent the pressure rise and discharge the internal gas to the outside. delete The method of claim 1, The upper safety plate and the lower safety plate is made of aluminum or aluminum alloy, the gasket is a safety plate of a lithium ion battery made of a polyolefin-based material. The method of claim 1, Safety plate of the safety plate is a current blocking pressure of 8 ~ 10kgf / ㎠, the bending pressure is 17kgf / ㎠ ± 3kgf / ㎠ safety plate of a lithium ion battery.