CN2762362Y

CN2762362Y - Single built-in PTC structure of square lithium ion battery

Info

Publication number: CN2762362Y
Application number: CN200420056226.5U
Authority: CN
Inventors: 高俊奎; 王荣; 孙杰; 秦兴才
Original assignee: Tianjin Lishen Battery JSCL
Current assignee: Tianjin Lishen Battery JSCL
Priority date: 2004-12-28
Filing date: 2004-12-28
Publication date: 2006-03-01
Anticipated expiration: 2014-12-28

Abstract

The utility model relates to a single built-in PTC structure of a square lithium ion battery. The square lithium battery is composed of a housing lid and an inner electrode group, wherein the electrode group comprises a positive electrode, a negative electrode and a membrane, wherein the positive electrode is formed in the way that lithium transition metal oxide is coated on an aluminum foil, and an aluminum conducting rod which is welded on the aluminum foil is used as an electrode ear and is connected with the housing lid; the negative electrode is formed in the way that carbon-graphite material is coated on a copper foil, and PTC is used as a conducting rod; the ear end of the one nickel electrode of the PTC is connected with the copper foil, and the ear end of the other nickel electrode is connected with the negative terminal of the lid. The utility model has the advantages that the whole structure of the battery is simple, and the action of the PTC switches is more rapid and effective, and the characteristics of the battery, such as storage characteristic, cycle characteristic, security characteristics of over charge and short circuit are examined. Thus, the experiment result shows the superior characteristics of the utility model.

Description

The built-in PTC structure of square lithium ion battery monomer

Technical field

The utility model relates to a kind of square lithium ion battery, particularly a kind of built-in PTC structure of square lithium ion battery monomer of PTC Switches (Positive Temperature Coefficient) being installed in the indoor design of cell,

Background technology

The anodal lithium transition-metal oxide that uses of square lithium ion battery, negative pole uses carbon negative pole material.The anodal transition metal oxide that takes off lithium when battery is full of electricity is very unstable, especially decomposes under higher temperature conditions, decomposes the oxygen of generation and the thermal runaway that negative pole lithium carbon compound vigorous reaction causes battery, sets off an explosion.

At present, the use of PTC Switches on lithium ion battery mainly is placed on the cell outer wall.When the battery external short circuit, PTC is raise by the short circuit current operative temperature and turn-offs; When battery overcharge, the temperature of battery raises, heating PTC and additional power source is turn-offed, thus played the effect of safeguard protection.

Studies show that the short circuit of battery and can cause when overcharging inside battery from heat production, the temperature contrast at each position of battery is bigger, the surface temperature that temperature inside is higher than battery is about more than 20 ℃.As far as possible early cut-out foreign current when battery temperature raises stops the continuation of temperature to be risen, and makes the thermal diffusion of entire cell produce greater than the heat of inside, reduces the temperature of battery, avoids the blast of battery.The built-in PTC structure of square lithium ion battery monomer just is based on this theoretical mechanism, makes PTC effect action in advance, and is more reliable effective, and compact conformation.

PTC is made up of Poly switches, nickel sheet and PP film, and Poly switches mainly is made up of PE and conductive carbon powder, and all having theoretically has the mechanical electronic hydraulic corrosion resistance to lithium ion battery, can work for a long time under electric pendular ring border and does not lose efficacy.

Summary of the invention

Main purpose of the present utility model provides a kind of square lithium ion battery of settling PTC in internal structure, overcharge to improve lithium ion battery, the short circuit security feature, and influence other electrical properties of battery hardly, be particularly suitable for safety requirements than higher lithium ion battery.

Square lithium ion battery is made up of housing lid and inner utmost point group, and utmost point group comprises positive and negative electrode and barrier film.Positive electrode is that lithium transition-metal oxide is coated on aluminium foil, and the welding of aluminum drainage strip is done lug and is connected with cap on aluminium foil.Negative electrode is that carbon graphite material is coated on Copper Foil, and welding nickel drainage strip is done lug and is connected with the cap negative terminal on Copper Foil.

Positioned inside PTC has a variety of, and is wherein a kind of as Fig. 1, uses PTC to replace the nickel drainage strip of negative electrode, and PTC one nickel lug end and Copper Foil connect, and another nickel lug end and lid negative terminal connect.Because PTC is positioned at the center of utmost point group, thus battery in short circuit and when overcharging under this mode PTC fastest, the most effective.

Also have PTC built-in as Fig. 2 in addition, PTC is positioned at the inboard of battery lid, and an end welds or be riveted on the negative terminal of lid, as parts of combination lid.When assemble, the nickel lug point of utmost point group is welded in the PTC other end of lid.

The utility model has the advantages that to make that whole battery structure is simple, and PTC Switches action is more fast, effective.

Use Fig. 1 structure, to storage characteristics, the cycle characteristics of battery, overcharge with the short circuit security feature and all investigate, experimental result has shown the advantageous characteristic of this structure.

Description of drawings

Fig. 1 is the built-in PTC schematic diagram of square lithium ion battery utmost point group switching centre

Fig. 2 is the inboard built-in PTC schematic diagram of square lithium ion battery lid

Accompanying drawing 1 symbol description:

The negative terminal of 1-battery case, 2-utmost point group, 3-Upper gasket, 4-aluminium anode ear, the negative copper foil of affluxion body of 5-utmost point group and PTC welding, 6 lids, 7 lids and PTC welding, 8PTC, 9-aluminium pole ears and lid welding

Accompanying drawing 2 symbol descriptions:

The negative terminal of 1-battery case, 2-utmost point group, 3-Upper gasket, 4-aluminium anode ear, 5-nickel negative electrode lug, 6 lids, 7 lids and PTC welding, 8PTC, 9-aluminium pole ears and lid welding, 10-nickel negative electrode lug and the welding of the PTC other end

Embodiment

As shown in Figure 1, when utmost point group 2 is reeled, PTC 8 is welded 5 as negative pole Ni lug and copper foil of affluxion body, after finishing the coiling operation utmost point group is inserted in the battery case 1, place Upper gasket 3, the other end and the welding of the negative terminal on the lid 67 with PTC, Al lug 4 and lid 6 weld 9 simultaneously, and follow-up assembling is with conventional lithium ion battery manufacture craft.PTC was positioned at the central inner of battery after assembling was finished.

As shown in Figure 2, after finishing the coiling operation utmost point group 2 is inserted in the battery case 1, place Upper gasket 3, Al lug 4 and lid 6 weld 9 simultaneously, an end and the welding of the negative terminal on the lid 67 with PTC 8, nickel negative electrode lug 5 welding 10 on the other end of PTC 8 and the utmost point group 2, follow-up assembling is with conventional lithium ion battery manufacture craft.PTC was between battery Upper gasket and lid after assembling was finished in this case.

Compare with conventional lithium ion battery, settle PTC (model RAYCHEM VTP210L) to press the 063450-1000mAh battery of accompanying drawing 1 assembling in the middle of the utmost point group of battery, the capacity of battery, discharge curve, cycle life, storage characteristics and high temperature performance all do not have marked difference.Be 12V and overcharge experiment, the shutoff temperature of battery surface drops to～80 ℃ (conventional batteries～100 ℃), and maximum temperature drops to～110 ℃ (conventional batteries～125 ℃); 60 ℃ of hard short circuit experiments, short circuit current reduce to～and 3.5A (conventional batteries～50A), maximum temperature drop to～and 80 ℃ (conventional batteries～120 ℃).In a word, the security feature of the built-in PTC design raising of lithium ion battery battery especially overcharges and the short circuit safety experiment.

Claims

1, the built-in PTC structure of a kind of square lithium ion battery monomer is characterized in that: square lithium ion battery is made up of housing lid and inner utmost point group, and utmost point group comprises positive and negative electrode and barrier film; Positive electrode is that lithium transition-metal oxide is coated on aluminium foil, and the welding of aluminum drainage strip is done lug and is connected with cap on aluminium foil; Negative electrode is that carbon graphite material is coated on Copper Foil, makes drainage strip with PTC, and PTC one nickel lug end and Copper Foil connect, and another nickel lug end and lid negative terminal connect.

2, the built-in PTC structure of a kind of square lithium ion battery monomer is characterized in that: square lithium ion battery is made up of housing lid and inner utmost point group, and utmost point group comprises positive and negative electrode and barrier film; Positive electrode is that lithium transition-metal oxide is coated on aluminium foil, and the welding of aluminum drainage strip is done lug and is connected with cap on aluminium foil; Negative electrode is that carbon graphite material is coated on Copper Foil, in the inboard of battery lid PTC is arranged, and PTC one end welds or be riveted on the negative terminal of lid, as parts of combination lid; The nickel lug point of utmost point group is welded in the PTC other end of lid.