WO2013010473A1

WO2013010473A1 - Method of winding cell of lithium ion battery

Info

Publication number: WO2013010473A1
Application number: PCT/CN2012/078720
Authority: WO
Inventors: 吴学科; 冯庆枝; 王立松
Original assignee: 深圳市吉阳自动化科技有限公司
Priority date: 2011-07-15
Filing date: 2012-07-16
Publication date: 2013-01-24
Also published as: CN102881946A; CN102881946B

Abstract

A method of winding a cell of a lithium ion battery comprises the following steps: A. preparing a cell material; B. measuring a parameter, and calculating a distance between adjacent tabs of an inner-layer pole piece and a distance between adjacent tabs of an outer-layer pole piece according to a predetermined formula; C. cutting tabs according to the calculated distance between the adjacent tabs of the inner-layer pole piece and the calculated distance between the adjacent tabs of the outer-layer pole piece; D. placing the inner-layer pole piece with the cut tabs, the outer-layer pole piece with the cut tabs, and an isolation film in a predetermined order, and then winding them into a cell. In this application, the distance between the adjacent tabs of the inner-layer pole piece and the distance between the adjacent tabs of the outer-layer pole piece are first calculated, then the tabs of the inner-layer pole piece and the tabs of the outer-layer pole piece are cut according to the calculation result, and the above parts are wound into the cell. Therefore, the positions of the tabs can be accurately determined, the work time and a lot of manpower are saved, and the work efficiency is improved.

Description

Lithium ion battery cell winding method

The present application relates to a lithium ion battery, and more particularly to a lithium ion battery cell winding method. Background technique

The replacement of traditional gasoline vehicles by new energy vehicles has become the consensus of all countries in developing the automobile industry. The power battery as the core component is considered by the industry to be the key to the development of new energy vehicles. At present, the power lithium battery is roughly divided into two manufacturing methods, one is a laminated core, and the other is a winding preparation battery, and the winding preparation core is divided into a square winding and a circular winding. Fig. 1 is a schematic view showing the structure of a ring-shaped battery cell, which includes a cell reel 1 1 , a pole piece 1 2 and a tab 13 . 2 is a schematic view showing the structure of each layer of cells after winding of the battery material, including the negative electrode sheet 21, the positive electrode sheet 23, and the separator 22. In different processes, the positions of the positive and negative electrodes can be interchanged. Each layer of cells contains two layers of separator, a positive electrode sheet and a negative electrode sheet.

When preparing the battery by ring winding, in order to ensure that the battery has a large enough capacity, we need to increase the length of the pole piece. As the length of the pole piece increases, the alignment of the ear is ensured during the winding process. difficult. Therefore, how to ensure the position of each tab that is cut during the laser cutting process is just the most important position to ensure that all the tabs are aligned after winding. This is also the process of preparing a large-capacity ring battery. The technical problems that need to be overcome most.

At present, the spacing calculation method used in the industry is to use the first winding, the polar ear is cut at the corresponding position on the winding core, and then the pole piece is deployed to manually measure the length of each pitch as the final cutting length. Because each cell often requires a large number of tabs, that is, a large number of tab pitches need to be obtained, the workload of this method is extremely large, and it is difficult to accurately position the tabs at one time because of human measurement errors. It is necessary to measure a number of times, and the measurement result is quite troublesome to input in the program, which takes a lot of manpower and time. In addition, if materials or processes are replaced, all the previous data will be invalidated. Therefore, when making large-capacity batteries, this kind of prescription The success rate of the law is very low.

Summary of the invention

The technical problem to be solved by the present application is to provide a lithium ion battery cell winding method capable of improving efficiency in view of the deficiencies of the prior art.

The technical problem to be solved by the present application is solved by the following technical solutions: A method for winding a lithium ion battery cell, comprising the following steps:

A. Prepare the battery material;

B. Measuring parameters, respectively calculating the adjacent pole pitch of the inner pole piece and the adjacent pole pitch of the outer pole piece according to a predetermined formula;

C. Cutting the tabs according to the calculated adjacent pole pitch of the inner pole piece and the adjacent pole pitch of the outer pole piece;

D. The inner pole piece cut out of the tab, the outer pole piece cut out of the tab and the diaphragm are placed in a predetermined order and then wound into a battery core.

The utility model has the beneficial effects that: in the specific implementation manner of the present application, since the adjacent pole pitch of the inner pole piece and the adjacent pole pitch of the outer pole piece are separately calculated, respectively, the inner layer is cut according to the calculation result. After the pole piece and the outer pole piece are wound into a battery core, the position of the ear can be accurately determined, which not only saves working time, but also saves a lot of manpower and improves work efficiency.

DRAWINGS

Figure 1 is a schematic view of the structure of a ring battery cell;

Figure 2 is a schematic view of the structure of each layer of cells;

Figure 3 is a schematic view of the pole piece after cutting the tab;

4 is a flow chart of a method for winding a lithium ion battery cell according to an embodiment of the present invention; FIG. 5 is a flow chart of obtaining a distance between adjacent tabs in a specific embodiment of the present application.

detailed description

The present application will be further described in detail below with reference to the accompanying drawings.

Since the present application uses a laser to cut the tabs at the corresponding positions of the pole pieces before winding, it must be ensured that each of the tab positions cut during the laser cutting process is just the overlap of all the tabs after winding. position. Winding alignment is mainly affected by the following factors, one is not The thickness of the diaphragm used in the same process battery is inconsistent with the thickness of the positive and negative electrodes; the second is that the thickness of the different lengths on the same roll piece is inconsistent; the third is that the tension between the inner core and the outer core is inconsistent during the winding process; The initial radius Γ. different.

Figure 3 is a schematic view of the pole piece after cutting the tab. The pole piece may be a positive electrode or a negative electrode. Where ^] is the width of the i-th tab, and L („ is the spacing between the i-1th tab and the i-th tab.

In the spirally wound cell, since the thickness of each layer is not more than 0.5 mm, it can be approximated that each turn of the winding is a standard circle, and the circumference can be calculated according to the diameter of the ring. And on this basis to find the pole spacing.

As shown in FIG. 4 and FIG. 5, the lithium ion battery cell winding method of the present application, an embodiment thereof, includes the following steps:

Step 401: Prepare the cell material.

Step 402: Measure the parameters, and calculate the distance between adjacent tabs of the inner pole piece and the adjacent pole pitch of the outer pole piece according to a predetermined formula. In one embodiment, the inner layer of each layer of cells is a negative pole piece and the outer layer is a positive electrode sheet; in another embodiment, the inner layer of each layer of cells is a positive electrode sheet and the outer layer is a negative electrode sheet.

Step 403: Cutting the tabs according to the calculated adjacent pole pitch of the inner pole piece and the adjacent pole pitch of the outer pole piece.

Step 404: The inner pole piece cut out of the tab, the outer pole piece cut out of the tab, and the separator are placed in a predetermined order, and then wound into a battery core.

Wherein step 402 specifically comprises the following steps: Step 501: measuring the thickness of the pole piece disposed in the inner layer; setting outside the thickness of the outer layer of the pole piece S; the thickness of the diaphragm ⁵ film. Step 502: Determine the thickness σ of each layer of cells. Each layer of cells includes two layers of separators, a layer of positive electrodes, a layer of negative electrodes, and a gap therebetween.

Step 503: Calculate the adjacent pole experimental spacing ^L of the pole piece material disposed in the inner layer according to the thickness σ of each layer of the core, respectively (inner and the pole piece material disposed on the outer layer) Adjacent polar test spacing:

( i > 1 ) Equation 1: r ₀ +( _l) + S +S film + (

(outside;) = ^ ^π

(i > 1) Equation 2; where: is the width of the i-th pole;

The radius of the cell reel;

0 in A is the experimental spacing between the i-1th ear and the ith pole of the inner layer; the outer 0 is the experimental spacing between the ilth ear and the ith pole of the outer layer. In one embodiment, the cell thickness of each layer thickness can be obtained by σ pole piece inner layer, the outer pole piece and the thickness of the outer film layers ⁵ obtained by adding the thickness of the diaphragm.

In another embodiment, each layer of cell thickness σ can be obtained by:

D_

Measuring the total thickness D of the m-layer cell material, the thickness of each layer of cells is σ = ^M . Step 504: Cut the inner pole piece tab according to the calculated shape, and cut out the outer pole piece tab according to the calculation.

Step 505: Winding the inner pole piece, the outer pole piece and the diaphragm into experimental batteries, and measuring the total deviation of the alignment between each K adjacent tabs ATM ^; k is a stage coefficient (ie, per k One pitch change once interval compensation). Step 506: Calculate the offset value of each phase according to Formula 3

C ― ^mod(;7^)

Formula 3

You can divide m compensation values by k, c

Step 507: Substituting the calculated pitch compensation values of each stage into Equation 4 and Equation 5, respectively, calculating the adjacent pole pitch of the inner layer ⁽ and the spacing of the adjacent adjacent poles ⁽ :

Formula 4

L

',(外'■) 2π Γ ₀ +( -1)σ + 3⁄4 + 3⁄4 +C

2 Equation 5 It should be understood that the above embodiments are only used to help the understanding of the present application, and should not be construed as limiting the present application. For the person skilled in the art, the above specific embodiments may be changed in accordance with the idea of the present application.

Claims

Rights request

A lithium ion battery cell winding method, comprising the steps of:

A. Prepare the battery material;

2. The method of winding a lithium ion battery cell according to claim 1, wherein the step B specifically comprises the following steps:

B1. The measurement is set in the thickness of the inner layer of the pole piece; is set outside the thickness of the outer layer; the thickness of the diaphragm is ⁵ ;

B2. Determine the thickness σ of each layer of cells, each layer of cells comprising two layers of separators, a layer of positive electrodes, a layer of negative electrodes and a gap therebetween;

Β 3. σ The thickness of each cell, adjacent electrode sheet material are disposed in the inner layer is calculated according to the formula ① and formula ② Experimental tab spacing ^[Sigma (within ') and disposed adjacent the outer pole piece material Outside the ear test interval

( i > l ) Equation 1:

^W _{(i) +} W _(i+X) )

r ₀ +( _l) + S +S film +

(outside;) = ^ ^π

² ( i > l ) Equation 2: where: ^« is the width of the ith pole; The radius of the cell reel; 0 in A is the experimental spacing between the ilth ear and the ith pole of the inner layer;

^Outer 0 is the experimental spacing between the i-l tabs and the i-th tab of the outer layer.

3. The method of winding a lithium ion battery cell according to claim 1, wherein the thickness σ of each layer of the core is specifically obtained by the following method: measuring the total amount of the m-layer battery material.

D_

For thickness D, the thickness of each layer of ^cells is σ = ^Μ .

4. The method of winding a lithium ion battery cell according to claim 3, wherein the step Β3 further comprises:

Β4. According to the calculated inner '> cut out the inner pole piece ear, according to the calculated outer '> cut out the outer pole piece ear;

Β 5. Wind the inner pole piece, the outer pole piece and the diaphragm into experimental cells, and measure the total misalignment ^A m between each adjacent tab. d ⁽ '/W;

C,

B6. According to formula 3, the pitch compensation value of each stage is calculated.

C ― ^mod(;7^)

( ) ^k formula 3;

c ,

B7. Substituting the calculated pitch compensation values for each stage into Equation 4 and Equation 5, respectively, calculate the adjacent interlayer pitch of the inner layer ⁷ and the outer adjacent pole pitch Α*ο: Formula 4

■ (

L ο + ₊₁₎ )

',(外'■) 2π Γ ₀ +(/-1)σ + 3⁄4 + 3⁄4

W k ² formula 5

The lithium ion battery cell winding method according to any one of claims 1 to 4, which The inner layer of each layer of cells is a negative electrode sheet, and the outer layer is a positive electrode sheet; or the inner layer of each layer of the battery core is a positive electrode sheet, and the outer layer is a negative electrode sheet.