CN2857237Y

CN2857237Y - Electrical core of lithium ion cell and hithium ion cell including the same

Info

Publication number: CN2857237Y
Application number: CNU2005201469465U
Authority: CN
Inventors: 渠冰; 顾晓峰
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2005-12-26
Filing date: 2005-12-26
Publication date: 2007-01-10
Anticipated expiration: 2015-12-26

Abstract

The utility model provides a core of lithium ion battery wherein the core comprises a cathode ear, a cathode sheet, an anode sheet and a diaphragm between the cathode sheet and the anode sheet. The first winding layer of the cathode sheet includes an extended cathode sheet wound inwards in a reverse direction. The cathode ear is welded on the extended cathode sheet in a direction facing the first winding layer of the cathode sheet. The cathode ear on the cathode sheet is arranged on the extended cathode sheet and covered by the cathode sheet of the first winding layer, thereby the joint of the cathode ear and the cathode sheet is prevented form short circuit which is caused by piercing the diaphragm.

Description

The electric core of lithium ion battery and the lithium ion battery that comprises this electricity core

Technical field

The utility model relates to the lithium ion battery field, relates in particular to a kind of electric core of lithium ion battery and the lithium ion battery that comprises this electricity core.

Background technology

Flourish along with information technology, and improving constantly to the environmental protection attention degree, lithium ion battery has obtained huge development with its high-energy-density, high voltage, advantage such as volume is little, in light weight, fail safe is good over past ten years, become one of main energy sources of communication class electronic product.

Lithium ion battery mainly comprises battery container and is sealed in housing interior electric core and nonaqueous electrolytic solution that wherein electric core is the critical piece of lithium ion battery.

Fig. 1 is the schematic diagram of the electric core of existing formation, and Fig. 2 is the schematic diagram of existing positive plate, and Fig. 3 is the schematic diagram of existing negative plate.Wherein, 1 expression positive plate, 2 expression barrier films, 3 expression negative plates, the coiling head end of 11,31 expression positive/negative plates, the coiling tail end of 12,32 expression positive/negative plates, 13, the both positive and negative polarity active material that applies on the 33 expression positive/negative plates, the lug of 14,34 expression positive/negative plates.

As shown in Figure 1, electric core generally includes barrier film 2 and by positive plate 1 that separates and negative plate 3, with positive and

negative plate

1 and 3 and barrier film 2 rotation successively that is stacked together reel and form.

As shown in Figure 2, positive plate 1 comprises anodal conducting base, on anodal conducting base, be coated with positive active material 13, and the tail end on anodal conducting base is welded with anode ear 14, the outer end of this anode ear 14 can block a shot with positive pole (not shown) weld together, lug compile on the conducting base electric current and the block with positive plate 1 between play the effect that is communicated with electric current.Usually, for anode ear 14 is welded on the positive plate 1 securely, the welding position on the positive plate 1 does not apply active material 13, promptly directly anode ear 14 is welded on the anodal conducting base, as shown in the figure.

As shown in Figure 3, the similar of the structure of negative plate 3 and the positive plate among Fig. 21.But in negative plate 3, negative electrode lug 34 is positioned on the negative plate 3 of the central core or first winding layer, is usually located at the coiling head end of negative plate 3, thereby after finishing the electric core of formation of reeling, negative electrode lug 34 can be positioned at the center of electric core.

In above-mentioned existing negative plate 3, because negative electrode lug 34 is welded on the head end 31 of negative plate 3, because the restriction of welding procedure, be easy to generate rough surface in the welding part, therefore reel with barrier film at positive/negative plate and form in the process of electric core, under certain pressure effect, above-mentioned rough surface is destroyed easily or is pierced through barrier film and cause the positive and negative plate short circuit.For positive plate 1, there are the problems referred to above equally.

In addition, positive and negative plate normally will be than long conducting base (being collector body) cutting section, applies corresponding both positive and negative polarity active material then on each section and makes.Therefore, in cutting process, sharp keen cut edge and wedge angle can be produced, perhaps also some burrs can be produced at two ends at the two ends of positive/negative plate.Thereby in winding process, cut edge that these are sharp keen and wedge angle and/or burr also may pierce through barrier film and cause battery short circuit.

Description of drawings

Fig. 1 is the schematic diagram of the electric core of existing formation;

Fig. 2 is the double-edged schematic diagram of existing positive plate;

Fig. 3 is the double-edged schematic diagram of existing negative plate;

Fig. 4 is the schematic diagram of a kind of embodiment of the present utility model;

Fig. 5 is the schematic diagram of another kind of embodiment of the present utility model;

Fig. 6 is the schematic diagram of another kind of embodiment of the present utility model;

Fig. 7 is the double-edged schematic diagram of the positive plate of a kind of embodiment of the utility model;

Fig. 8 is the double-edged schematic diagram of the negative plate of a kind of embodiment of the utility model.

The utility model content

The purpose of this utility model provides the electric core that a kind of welding part that can avoid negative lug and negative plate punctures the lithium ion battery of barrier film.

The electric core of the lithium ion battery that the utility model provides comprises that negative electrode lug, positive/negative plate and the interval membrane coil between positive/negative plate are around forming, first winding layer of wherein said negative plate comprises the extension negative plate of reeling in the other direction inwardly, and described negative electrode lug is welded on this extension negative plate and towards first winding layer of negative plate.

Therefore, pass through the technical solution of the utility model, because negative electrode lug is positioned at first winding layer that extends on the negative plate and face negative plate, be that negative electrode lug on the negative plate is covered by first winding layer of negative plate, cause the short circuit between the positive/negative plate so the welding part of negative electrode lug and negative plate can not puncture barrier film.

Embodiment

Describe embodiment of the present utility model with reference to the accompanying drawings in detail.

The electric core of the lithium ion battery that the utility model provides comprises negative electrode lug 34, positive/

negative plate

1 and 3 and the barrier film 2 between positive/negative plate at interval, wherein, first winding layer of described negative plate comprises the extension negative plate 36 of reeling in the other direction inwardly, and described negative electrode lug is welded on this extension negative plate 36 and towards first winding layer of negative plate.

As shown in Figure 4, negative electrode lug 34 is positioned at the coiling head end 31 that extends negative plate 36.When the barrier film between coiling positive/negative plate and positive/negative plate forms electric core, at first negative plate 3 is reeled to form around its head end 31 and extend negative plate 36, thereby after negative plate 3 is reeled a circle, negative electrode lug 34 is just covered by the negative plate 3 of first winding layer, so the welding part between negative electrode lug 34 and the negative plate 3 just can not puncture the barrier film 2 between negative plate 3 and the positive plate 1.

In the embodiment shown in fig. 4, negative plate 3 at first begins to reel from extending negative plate 36, turn back from the tail end that extends negative plate 36 then and continue to reel and form first winding layer, thereby the negative electrode lug 34 that will extend on the negative plate 36 is coated between the negative plate of the extension negative plate 36 and first winding layer.Therefore, the negative electrode lug 34 of welding is directly covered by negative plate itself on the negative plate 3, but the reverse side position corresponding with negative electrode lug 34 positions directly do not covered by negative plate itself on negative plate 3.

Cause the short circuit between the positive/negative plate in order further to guarantee position that negative electrode lug 34 and negative plate 3 weld can not puncture barrier film 2, another kind of preferred embodiment is provided in Fig. 5.

As shown in Figure 5, reverse side position corresponding with negative electrode lug 34 positions on the negative plate 3 also itself is covered by negative plate 3, is promptly covered by the negative plate 3 of second winding layer.Particularly, at first reel and extend the negative plate that negative plate 36 forms first winding layer, and then the coiling negative plate forms the negative plate of second winding layer, thereby be welded on the negative plate that first winding layer is faced in the front of extending negative electrode lug 34 on the negative plate 36, the negative plate of second winding layer is then faced at the back side, that is to say, extend negative plate 36 between the negative plate of first winding layer and second winding layer.

Fig. 6 and Fig. 5 are basic identical, and difference has been to dot out the position that barrier film 2 may exist in Fig. 6.

As shown in Figure 6, can be provided with barrier film 2 between the negative plate 3 of reeling, for example, barrier film 2 can extend inward between the negative plate that extends negative plate 36 and first winding layer and/or second winding layer.

At the embodiment of above-mentioned Fig. 4, can between the negative plate 3 of reeling, barrier film 2 be set equally, it is done diagram and explanation no longer in addition.

For electric core, have only positive/negative plate and at interval the barrier film between positive/negative plate, could electrochemical reaction take place and produce electric energy by positive negative active material and the barrier film on the positive/negative plate one by one at once.Since extend negative plate 36 once or both sides be not to set gradually barrier film and positive plate, therefore this extension negative plate 36 there is no contribution to the power supply of electric core or battery.

Therefore, in order to save the use amount of active material, preferably described extension negative plate at least the one side on do not have negative electrode active material.

In addition, as described in the background section, form in the process of electric core at coiling positive/negative plate and barrier film, the edge at positive/negative plate two ends and wedge angle also may puncture barrier film and cause the positive/negative plate short circuit.

In order to prevent this problem, preferably can carcass be set at the positive/negative plate two ends, promptly utilize adhesive plaster that the two ends of positive/negative plate are encased.

As shown in Figure 7, puncture barrier film for the coiling head end edge that prevents positive plate 1 or wedge angle and cause positive/negative plate short circuit in the electric core, coated carcass 15 at the coiling head end of positive plate 1.

As shown in Figure 8, puncture barrier film for the coiling tail end edge that prevents negative plate 3 or wedge angle and cause positive/negative plate short circuit in the electric core, coated carcass 35 at the coiling tail end of negative plate 3.

In addition, for the anode ear position that prevents positive plate 1 punctures barrier film and causes short circuit between the positive/negative plate, preferably can also on the anode ear 14 of positive plate 1, carcass 15 be set.

In addition, the also claimed a kind of lithium ion battery of the utility model with above-mentioned electric core.The concrete formation and the preparation method of lithium ion battery can adopt existing technology, for example can be with reference to the many pieces of patent documentations about lithium ion battery by Biyadi Co Ltd's application.

Claims

1, a kind of electric core of lithium ion battery, this electricity core comprises negative electrode lug, positive/negative plate and the interval barrier film between positive/negative plate, it is characterized in that, first winding layer of described negative plate comprises the extension negative plate of reeling in the other direction inwardly, and described negative electrode lug is welded on this extension negative plate and towards first winding layer of negative plate.

2, electric core as claimed in claim 1, wherein, described negative electrode lug is welded on the coiling head end of described extension negative plate.

3, electric core as claimed in claim 1, wherein, described extension negative plate at least the one side on do not have negative electrode active material.

4, electric core as claimed in claim 1 wherein, has carcass at the coiling head end of described positive plate.

5, electric core as claimed in claim 1 wherein, has carcass on the anode ear of described positive plate.

6, electric core as claimed in claim 1 wherein, has carcass at the coiling tail end of described negative plate.

7, a kind of lithium ion battery is characterized in that, this battery comprises electric core as claimed in claim 1.