阅读说明：本技术 一种锂离子动力电芯的电极连接方法及电极连接片 (Electrode connection method and electrode connection sheet of lithium ion power battery cell ) 是由 吴俊华 王正伟 于 2021-01-12 设计创作，主要内容包括：本发明公开了一种锂离子动力电芯的电极连接方法及电极连接片,提供2个电极连接片,由波纹部和平板部相连构成,波纹部和平板部之间经折弯连接,将平板部折弯至波纹部一侧时,平板部和波纹部之间形成弹性连接关系,使平板部获得远离波纹部方向的弹性势能；将1个电极连接片的波纹部压在阳极极耳上,平板部折弯至波纹部上方并与阳极电芯盖板固定；将另1个电极连接片的波纹部压在阴极极耳上,平板部折弯至波纹部下方并与阴极电芯盖板固定,实现动力电芯的电极引出。本发明在保证动力电芯电极引出的同时避免了工艺过程中产生金属粉尘造成的影响；导电的功能持续有效且可靠。(The invention discloses an electrode connecting method and an electrode connecting sheet of a lithium ion power battery cell.A plurality of 2 electrode connecting sheets are provided and are formed by connecting a corrugated part and a flat plate part, the corrugated part and the flat plate part are connected through bending, when the flat plate part is bent to one side of the corrugated part, an elastic connecting relation is formed between the flat plate part and the corrugated part, so that the flat plate part obtains elastic potential energy in the direction away from the corrugated part; pressing the corrugated parts of the 1 electrode connecting sheets on the anode tabs, and bending the flat plate part to the upper part of the corrugated parts and fixing the flat plate part with the anode cell cover plate; and pressing the corrugated parts of the other 1 electrode connecting sheet on the cathode lug, and bending the flat plate part to the lower part of the corrugated parts and fixing the flat plate part with the cathode electric core cover plate to realize the electrode extraction of the power electric core. The invention ensures the leading-out of the power cell electrode and avoids the influence caused by metal dust generated in the process; the function of conduction continues to be efficient and reliable.)

1. An electrode connection method of a lithium ion power battery cell is used for electrically connecting an anode tab and an anode cell cover plate of the lithium ion power battery cell and electrically connecting a cathode tab and a cathode cell cover plate of the lithium ion power battery cell, and is characterized by comprising the following steps of:

(1) providing 2 electrode connecting sheets, wherein each electrode connecting sheet is formed by connecting a corrugated part and a flat plate part, the corrugated parts and the flat plate parts are connected through bending, and when the flat plate parts are bent to one side of the corrugated parts, an elastic connection relation is formed between the flat plate parts and the corrugated parts, so that the flat plate parts obtain elastic potential energy in the direction away from the corrugated parts;

(2) pressing the corrugated parts of the 1 electrode connecting sheets on the anode tabs, and bending the flat plate part to the upper part of the corrugated parts and fixing the flat plate part with the anode cell cover plate; and pressing the corrugated parts of the other 1 electrode connecting sheets on the cathode lug, and bending the flat plate part to the lower part of the corrugated parts and fixing the flat plate part with the cathode electric core cover plate, thereby realizing the electrode extraction of the power electric core.

2. The method of claim 1, wherein the method comprises: the lithium ion power battery cell is a cylindrical battery cell, the battery cell pole piece is wound into a cylindrical shape, and the width of the corrugated part of the electrode connecting piece is set so that the electrode connecting piece can be in contact with the electrode lug on each wound circumference when being compressed.

3. The method of claim 1, wherein the method comprises: the wave trough and the wave crest of the corrugated part are arranged in parallel to the bending.

4. The method of claim 3, wherein the method comprises: the wave troughs and the wave crests of the corrugated parts form a triangular layout in the cross section direction.

5. The method of claim 1, wherein the method comprises: a folding line is formed at the bending part of the electrode connecting sheet in a preprocessing mode, and the electrode connecting sheet is bent along the folding line to enable the flat plate part to lean against the corrugated part during installation.

6. The method of claim 1, wherein the method comprises: a plurality of small holes which are arranged at intervals are arranged at the bending position of the electrode connecting sheet in advance, the centers of the small holes are positioned on the same straight line, and the small holes are connected and bent along the centers of the small holes during installation so that the flat plate part is close to the corrugated part.

7. The utility model provides an electrode connection piece for lithium ion power electricity core which characterized in that: the corrugated flat plate is a metal sheet formed by connecting a corrugated part and a flat plate part, a bending structure is arranged between the corrugated part and the flat plate part, and the metal sheet is bent at the bending structure so that the flat plate part is positioned on one side of the corrugated part and the flat plate part and the corrugated part form an elastic connection relation.

8. The electrode tab for a lithium-ion power cell of claim 7, wherein: the wave trough and the wave crest of the corrugated part are arranged in parallel to the bending.

9. The electrode tab for a lithium ion power cell of claim 8, wherein: the wave troughs and the wave crests of the corrugated parts form a triangular layout in the cross section direction.

10. The electrode tab for a lithium-ion power cell of claim 7, wherein: the bending structure is a crease formed by pretreatment, or the bending structure is a plurality of small holes which are arranged at intervals and are preset at a bending position, and the centers of the small holes are positioned on the same straight line.

Technical Field

The invention relates to a lithium ion power battery, in particular to an electrode connecting method for connecting an electrode plate of a power battery cell and a battery cell cover plate and an electrode connecting sheet used for the method.

Background

In the preparation process of the lithium ion power battery cell, the cathode and the anode in the battery cell need to be connected with the cover plate assembly through the connecting sheet, so that the cathode and the anode on the outer surface of the battery cell are correspondingly communicated, and the charging and discharging requirements in the application process are met.

Because the overcurrent requirement of the power battery core is high, the influence of the electrode connection structure on the performance of the battery is large. In the prior art, the connection method of the electrodes generally comprises the following steps: (1) leading out by ultrasonic welding connecting sheets (multi-pole ear). Ultrasonic bonding can produce a large amount of metal dust that probably leads to electric core short circuit in the use, and manufacturing process need avoid the dust too much to remain inside electric core through welding while removing dust to still need paste the protection sticky tape on the face of weld after the welding. The method has the advantages of complex manufacturing process, high cost, high quality control difficulty and certain quality hidden danger. For example, in the chinese invention application CN104475962A, in order to solve the welding problem, a special welding machine is designed, when a tab of a lithium battery is welded, a blowing device blows welding slag generated by welding to adhesive paper in an ultrasonic welding dust retaining groove, the welding slag is adhered by the adhesive paper, and after the welding is completed, the adhesive paper on the upper layer of the inner wall of the dust retaining groove is torn off for the next welding. The special equipment is adopted to increase the production cost. In addition, certain pole plate area needs to be occupied by ultrasonic welding, and the partial blank area needs to be reserved in the pole plate manufacturing process, so that the efficiency of the pole plate manufacturing process is influenced. Meanwhile, the energy cannot be stored in the welding area, and the energy density of the battery cell is influenced. (2) The method is characterized in that enough long lugs are reserved on a pole plate, then redundant lug materials are cut off through a lug secondary processing process (usually laser or die cutting), and the residual lugs with certain shapes are connected with a connecting piece through ultrasonic welding or laser welding (a full lug mode). Although the method does not occupy the area of the pole plate, the ultrasonic welding still generates a large amount of metal dust which can cause short circuit of the battery core in the using process, the manufacturing process needs to avoid excessive dust from remaining in the battery core by welding and dedusting, and a protective adhesive tape needs to be attached to the welding surface after the welding is finished. If laser welding is used, certain metal dust is generated in the manufacturing process. The manufacturing process needs to avoid excessive dust remaining inside the battery core by welding and removing dust at the same time. Therefore, the preparation process also has the problem of high difficulty in quality control and certain hidden quality danger. And (3) for the full-lug structure, a certain compact and relatively flat structure is formed by flattening the lugs of the polar plate, and then the flattened lugs and the connecting plates are connected through laser welding. For example, the chinese invention application CN110718665A discloses a combined flattening method for a lithium battery tab, which ensures the flattening effect by the combination of ultrasonic flattening and mechanical flattening. The two problems of the process method are difficult to solve, firstly, metal dust is generated in the kneading and laser welding processes, and excessive dust is prevented from remaining in the battery core in the manufacturing process by kneading or welding and removing dust. The difficulty of quality control is high, and certain quality hidden danger also exists. Secondly, the flattened product prevents the electrolyte from infiltrating into the product, and the efficiency in the post-process liquid injection process is very low, which is about 70% of the efficiency under the condition of the conventional non-flattening process.

Therefore, there is a need for improved methods of tab attachment for lithium ion power cells.

Disclosure of Invention

The invention aims to provide an electrode connecting method of a lithium ion power battery cell, which avoids the generation of metal dust in the manufacturing process and simplifies the process on the premise of ensuring the electrode leading-out effect. Another object of the present invention is to provide an electrode connecting sheet for realizing the above electrode connecting method.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: an electrode connection method of a lithium ion power battery cell is used for electrically connecting an anode tab and an anode cell cover plate of the lithium ion power battery cell and electrically connecting a cathode tab and a cathode cell cover plate of the lithium ion power battery cell, and comprises the following steps:

(1) providing 2 electrode connecting sheets, wherein each electrode connecting sheet is formed by connecting a corrugated part and a flat plate part, the corrugated parts and the flat plate parts are connected through bending, and when the flat plate parts are bent to one side of the corrugated parts, an elastic connection relation is formed between the flat plate parts and the corrugated parts, so that the flat plate parts obtain elastic potential energy in the direction away from the corrugated parts;

(2) pressing the corrugated part of 1 electrode connecting sheet on an anode tab, bending the flat plate part to the upper part of the corrugated part and fixing the flat plate part with an anode cell cover plate, and welding and fixing the anode cell cover plate with a cell shell; and pressing the corrugated part of the other 1 electrode connecting sheet on a cathode lug, bending the flat plate part to the lower part of the corrugated part and fixing the flat plate part with a cathode electric core cover plate, and welding and fixing the cathode electric core cover plate with an electric core shell, thereby realizing the electrode extraction of the power electric core.

Among the above-mentioned technical scheme, the electrode connection piece that provides generally is the foil, can keep certain resilience force after being close to 180 degrees bends, makes the flat plate portion obtain and keeps away from the elastic potential energy of corrugated portion direction to guarantee its good contact with electric core utmost point ear and electric core apron. The arrangement of the corrugated part can ensure effective contact with the lug and can avoid relative rotation between the connecting sheet and the lug. The fixing method between the flat plate part and the battery core cover plate can adopt rivet riveting, or fix the flat plate part on the battery core cover plate by laser welding or ultrasonic welding in advance.

According to the further technical scheme, the lithium ion power battery cell is a cylindrical battery cell, the battery cell pole piece is wound into a cylindrical shape, and the width of the corrugated part of the electrode connecting piece is set so that the electrode connecting piece can be in contact with the electrode lug on each wound circumference when being compressed.

In the technical scheme, the wave troughs and the wave crests of the corrugated parts are arranged in parallel to the bending.

According to the preferable technical scheme, the wave troughs and the wave crests of the corrugated parts form a triangular layout in the cross section direction.

According to the preferable technical scheme, a folding line is formed at the bending part of the electrode connecting sheet in a preprocessing mode, and the flat plate part is enabled to lean against the corrugated part by bending along the folding line during installation.

Or, a plurality of small holes arranged at intervals are preset at the bending position of the electrode connecting sheet, the centers of the small holes are positioned on the same straight line, and the small holes are connected and bent along the centers of the small holes during installation so that the flat plate part is close to the corrugated part.

In order to achieve another object of the present invention, an electrode connecting sheet for a lithium ion power battery cell is provided, which is a metal sheet formed by connecting a corrugated portion and a flat portion, wherein a bent structure is provided between the corrugated portion and the flat portion, and the metal sheet is bent at the bent structure so that the flat portion is located at one side of the corrugated portion and the flat portion and the corrugated portion form an elastic connection relationship.

The width, the thickness and the corrugation number of the corrugation bending of the electrode connecting sheet can be designed by a person skilled in the art according to the overcurrent capacity of the battery cell, but the width dimension should meet the requirement that the electrode lug of the anode (cathode) can be contacted with the electrode lug on each circumference after being compressed as much as possible, so that the optimal conductive performance is realized. On the premise of meeting the overcurrent capacity, the pressing force between the connecting sheet and the lug can be adjusted by adjusting the thickness.

In the technical scheme, the wave troughs and the wave crests of the corrugated parts are arranged in parallel to the bending.

According to the preferable technical scheme, the wave troughs and the wave crests of the corrugated parts form a triangular layout in the cross section direction.

In the above technical scheme, the bending structure is a crease formed by pretreatment, or the bending structure is a plurality of small holes arranged at intervals and preset at a bending position, and the centers of the small holes are located on the same straight line. The structure of the bending position can be cancelled and is ensured through equipment or a tooling jig in the machining process.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

1. the invention abandons the conventional concept of welding connection in the prior art, creatively designs the battery connecting sheet which has a simple structure and generates elasticity, and the elasticity is generated by bending the connecting sheet, so that the influence caused by metal dust generated in the process is avoided while the leading-out of the power battery core electrode is ensured;

2. the electrode connecting sheet disclosed by the invention has the advantages that on one hand, the contact effect of the connecting sheet and the lug is well ensured by utilizing the elasticity, so that the conductive function is continuous, effective and reliable, on the other hand, the effective contact and reliable conductivity with the lug on each winding circumference of the winding battery cell can be realized by arranging the corrugated structure, the contact area is further strengthened by the corrugated effect, and the conductive capacity of the connecting sheet is improved.

3. The corrugated structure's setting has still prevented the inside book core of electric core from taking place rotary motion, has guaranteed the reliability of connection, avoids the connection piece to take place the fracture, and this kind of electrically conductive effect will make the internal resistance of electric core lower, and it is littleer to generate heat, is favorable to the effective performance of electric core electric quantity and life's extension.

4. The manufacturing process of the invention is connected by physical contact, the connection mode is simple, and the investment of a large amount of fixed assets such as laser welding, ultrasonic welding and the like, the occupation of manufacturing fields and the energy consumption in the manufacturing process are avoided, so that the manufacturing cost can be greatly reduced.

Drawings

FIG. 1 is a schematic structural diagram of an initial state of an electrode connecting sheet in an embodiment of the present invention;

FIG. 2 is a schematic view showing a bent state of an electrode connecting piece;

FIG. 3 is a perspective view of the disassembled and bent state;

fig. 4 is a schematic view of the electrode connection pad after installation.

Wherein: 1. a corrugated portion; 2. a flat plate portion; 3. folding; 4. an anode tab; 5. an anode cell cover plate; 6. and a through hole.

Detailed Description

The invention is further described with reference to the following figures and examples:

the first embodiment is as follows: referring to fig. 1, an electrode connecting sheet for a lithium ion power cell is a metal sheet formed by connecting a corrugated portion 1 and a flat plate portion 2, wherein a crease 3 is preset between the corrugated portion 1 and the flat plate portion 2. As shown in fig. 1, the corrugated portion in the present embodiment adopts a cross-section similar to a triangular folded structure, and as can be seen in fig. 3, a through hole 6 is formed in the center of the corrugated portion to facilitate electrolyte injection.

As shown in fig. 2 and 3, the metal sheet is bent along the fold 3 so that the flat plate portion 2 is located at one side of the corrugated portion 1, and the flat plate portion 2 and the corrugated portion 1 form an elastic connection relationship, so that the flat plate portion obtains elastic potential energy in a direction away from the corrugated portion.

The electrode connecting sheet is used for the electrode connecting method of the lithium ion power battery cell, and the electric connection of the anode tab and the anode cell cover plate of the lithium ion power battery cell and the electric connection of the cathode tab and the cathode cell cover plate of the lithium ion power battery cell are respectively realized. The method comprises the following steps:

(1) providing 2 of the electrode connecting sheets;

(2) as shown in fig. 4, the corrugated portion 1 of 1 electrode connecting sheet is pressed on the anode tab 4, the flat plate portion 2 is bent to be above the corrugated portion 1 and fixed with the anode cell cover plate 5, and then the anode cell cover plate is welded and fixed with the cell casing (not shown in the figure).

In the same method, the corrugated part of the other 1 electrode connecting sheet is pressed on the cathode lug, the flat plate part is bent to the lower part of the corrugated part and is fixed with the cathode electric core cover plate, and the cathode electric core cover plate is fixed with the electric core shell in a welding way, so that the electrode extraction of the power electric core is realized.