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【Rayclass | 锐课堂】Laser Welding for Power Battery
Date:2019-12-13Source:Original article

激光焊接作为一种高效精密的连接方式,具有明显的优势:加工效率高、加工精度高、热影响区小、焊件变形小、自动化程度高等等。将激光焊接应用在汽车动力电池焊接上可以大大提高其安全性、可靠性和使用寿命。

As a high-efficiency and precise connection method, laser welding has obvious advantages such as high processing efficiency, high processing precision, small heat-affected zone, small deformation of weldment and high degree of automation. The application of laser welding for automotive power battery can greatly improve its safety, reliability and service life. 

 

动力电池的激光焊接部位多,其材料主要是铝合金,少量部位采用紫铜等材料,还有极少数采用不锈钢作为电池外壳,在这些材料中,镍和不锈钢的激光焊接工艺相对较为简单,也更为成熟,但是铝合金和紫铜的激光焊接依然存在较多的难点。除材料特性的影响之外,焊接接头的状态也会对焊接效果产生较大影响。

The laser welding materials used for power batteries are mainly aluminum alloys, a small amount of materials such as copper and nickel, and also stainless steels as battery casings. Among these materials, the laser welding process of nickel and stainless steel is relatively mature, but the laser welding of aluminum alloy and copper still has more difficulties. In addition to the influence of material properties, the state of the welded joint also has a large effect on the welding effect. 

 

 

待焊接的材料种类及状态

 

待焊材料种类

Type of Material

 

铝合金和紫铜作为待焊接的材料时,其常规方式的激光焊接效果不良的主要原因在于:

When aluminum alloy and copper are used as the material to be welded, the main reasons for the poor laser welding effect of the conventional method are:

 

①两者对于光纤激光来说均属于高反材料,对光纤激光的吸收率不高,导致焊接过程稳定性较差;

Both are high-reflective materials for fiber lasers, and the absorption rate of fiber lasers is not high, resulting in poor soldering process stability.

 

②两者的导热性能较好,焊缝成型困难,易产生气孔。

Both thermal conductivities are good, the weld formation is difficult, and the pores are easily generated.

 

同时这两种材料也存在一定的差异,相对来说,铝合金对光纤激光的吸收率比紫铜的高,而紫铜的导热性能更优于铝合金的,所以两者激光焊接难点的解决办法有相同的地方,也存在着一定的差异:

Meanwhile, there are certain differences between the two materials. Relatively speaking, the absorption rate of aluminum alloy to fiber laser is higher than that of copper, and the thermal conductivity of copper is better than that of aluminum alloy. Therefore, the solutions to the difficulties of laser welding in the two have the same place, and there are certain differences.

 

铝合金

Aluminum Alloy

1

采用相对较小的聚焦光斑(0.1mm~0.3mm)进行焊接;

Welding with a relatively small focused spot (0.1mm to 0.3mm);

2

焊接速度不能太低,控制在60mm/s以上;

Controlled welding speed over 60mm / s;

3

采用光纤-半导体激光复合焊接;

Fiber-semiconductor laser hybrid welding;

4

采用摆动焊接。

wobble welding.

紫铜

Copper

1

采用较小的聚焦光斑(0.02mm~0.2mm)进行焊接;

Welding with a relatively small focused spot (0.02mm to 0.2mm);

2

焊接速度要快,建议100mm/s以上;

Controlled welding speed over 100mm / s;

3

采用摆动焊接。

wobble welding.

 

待焊材料状态

States of Materials

 

本文中所述的待焊材料状态是指材料的表面清洁度、预处理程度,这些情况均会导致焊缝质量变差,具体的结果表现及解决方案:

The state of the material refers to the surface cleanliness and pretreatment degree of the material, which will lead to the deterioration of the weld quality. The specific results and solutions are shown below:

材料表面有杂质

Impurities

难点表现:

焊缝存在气孔,密封性不够,强度不够;

焊缝有爆点,产品报废。

Performance:

Pores in the weld, lack of airtightness and strength.

Burst point, scrapped product.

 

解决方案:

待焊材料焊接前需去除油污、水渍等杂质。

Solutions:

Remove impurities such as oil and water in advance.

铝合金表面氧化物未清理

Un-cleaned Oxide in the Surface of AL

难点表现:

焊缝气孔较多,密封性不够,强度不够;

成型不稳定,良品率降低。

Performance:

Pores in the weld, lack of airtightness and strength.

Unstable molding, reduced yield.

 

解决方案:

待焊材料焊前进行去氧化膜处理,然后尽快进行焊接。

Solutions:

Remove the oxide film and then welding ASAP.

材料待焊处加工粗糙

Rough Processing

难点表现:

成型不均匀,外观较差;

容易出现焊漏,无密封性。

Performance:

Uneven molding, poor appearance.

Easy to welding leakage, no sealing.

 

解决方案:

材料进行机加工处理,需平整无变形。

Solutions:

Process to free of deformation before welding.

 

 

焊缝所属部件类型及要求

Types and Requirements

 

目前主流的汽车动力电池有三种,分别是方形电池圆柱电池以及软包电池,最常用的是方形电池,并且它也是采用激光焊接部位最多的电池类型,另外两类电池市场份额以及激光焊接需求均相对要少很多。焊缝主要存在的问题是强度不够、密封性不够和成型不好,导致这些问题的产生,其共性是因为焊接工艺选择不正确,此外还有待焊部位结构及其焊缝要求所导致的焊接难点,具体情况及解决方案:

At present, there are three types of mainstream automotive power batteries, namely square batteries, cylindrical batteries and soft pack batteries. The most commonly used prismatic batteries are the ones that use the most laser-welded parts. The other two types of battery market share and laser welding requirements are relatively small. The main problems of welds are insufficient strength, insufficient sealing and poor forming, which leads to the occurrence of these problems. The commonality is due to the incorrect selection of the welding process. In addition, there are welding difficulties caused by the structure of the welded parts and the requirements of the welds. The specific conditions and solutions are shown as below:

 

软包电池部件

Soft Pack Battery

极耳/汇流排

Tab/Busbar

焊接难点:

材料薄,多片叠焊易虚焊,导致强度不够,导电性不好。

解决方案:

控制来料平整度;

设计优良性能的夹具,控制装夹间隙。

Difficulties:

Thin material, cold joint, poor of strength and electrical conductivity.

Solutions:

Control the flatness.

Control the clamping gap.

 

焊接难点:

焊缝连接宽度不够导致强度不够。

解决方案:

选用小纤芯光纤激光器,采用摆动焊接。

Difficulties:

Insufficient weld joint width results in insufficient strength.

Solutions:

Small core fiber lasers are used for wobble welding.

 

圆柱电池部件

Cylindrical Battery

21700电池盖帽

21700 battery caps

焊接难点:

材料薄,易烧穿,强度达不到。

Difficulties:

Thin material, easy to burn through, lack of strength.

 

解决方案:

控制来料一致性;

设计优良性能的夹具,控制装夹间隙;

选用小纤芯光纤激光器,并用振镜高速(300mm/s以上)焊接。

Solutions:

Control material consistency.

Control the clamping gap.

Use small core fiber laser, and the galvanometer is used for high speed (300mm/s or more) welding.

模组

Module

焊接难点:

熔深要求较大,焊缝成型较差。

Difficulties:

Deep penetration requirements, poor weld formation.

 

解决方案:

激光器纤芯选择50μm~100μm,使用较高功率进行高速(80mm/s以上)焊接。

Solutions:

The laser core is selected from 50 μm to 100 μm, and high-speed (80 mm/s or more) soldering is performed using higher power.

 

方形电池部件

Square Battery

注液孔、翻转片、极柱、防爆阀

Filling port, Flip chip, Column, Burst vent 

注液孔

翻转片

极柱

防爆阀

焊接难点:

气孔多,容易出现爆点,导致密封性不够。

Difficulties:

More vents, easy to explode, lack of sealing.

 

解决方案:

提高待焊部位的清洁度;

选用50μm纤芯的光纤激光器,焊接速度可适当提高。

Solutions:

Improve the cleanliness.

Use 50 μm core fiber laser, increase welding speed.

壳体封口

Shell Seal

焊接难点:

气孔多,容易出现爆点,导致密封性不够。

解决方案:

提高待焊部位的清洁度;

选用50μm纤芯的光纤激光器,焊接速度可适当提高;

选用小纤芯光纤激光器+半导体激光器进行复合焊接。

Difficulties:

More vents, easy to explode, lack of sealing.

Solutions:

Improve the cleanliness.

Use 50 μm core fiber laser, increase welding speed.

Fiber-semiconductor laser hybrid welding.

 

焊接难点:

方形焊缝四个拐角处容易烧穿,导致密封性不够。

解决方案:

选择加速性能更好的焊接平台;

采用较高的焊接速度,缩短拐角处激光的照射时间。

Difficulties:

easy to burn through, lack of sealing.

Solutions:

Welding platform with better acceleration performance.

High welding speed is used to shorten the laser irradiation time at the corners.

 

焊接难点:

焊缝成型不均匀,加工效率不够高。

解决方案:

选用小纤芯光纤激光器+半导体激光器进行复合焊接。

Difficulties:

Un-formed uniformly welding seam and low processing efficiency.

Solutions:

Fiber-semiconductor laser hybrid welding.

汇流排

Busbar

焊接难点:

材料薄,多片叠焊易虚焊,导致强度不够,导电性不好。

解决方案:

控制来料平整度;

设计优良性能的夹具,控制装夹间隙。

Difficulties:

Thin material, cold joint, poor of strength and electrical conductivity.

Solutions:

Control the flatness.

Control the clamping gap.

 

焊接难点:

焊缝连接宽度不够导致强度不够。

解决方案:

选用小纤芯光纤激光器,采用摆动焊接。

Difficulties:

Insufficient weld joint width results in insufficient strength.

Solutions:

Small core fiber lasers are used for wobble welding.

侧板

Siding

焊接难点:

焊接部位多,效率要求高。

Difficulties:

Many welding parts and high efficiency.

 

解决方案:

选择高功率光纤激光器,进行远程扫描焊接。

Solutions:

Select a high-power fiber laser for remote scanning welding.

软连接

Soft connection

焊接难点:

材料薄,多片叠焊易虚焊,导致强度不够,导电性不好。

解决方案:

控制来料平整度;

设计优良性能的夹具,控制装夹间隙。

Difficulties:

Thin material, cold joint, poor of strength and electrical conductivity.

Solutions:

Control the flatness.

Control the clamping gap.

 

焊接难点:

焊缝连接宽度不够导致强度不够。

解决方案:

选用小纤芯光纤激光器,采用摆动焊接。

Difficulties:

Insufficient weld joint width results in insufficient strength.

Solutions:

Small core fiber lasers are used for wobble welding.

 

激光器推荐

 

为了能够解决在动力电池焊接中所遇到的难题,针对上述解决方案中所涉及的激光器,锐科激光重点推出了几款适用于动力电池激光焊接的小纤芯光纤激光器、配合双激光复合焊接用的半导体激光器以及优质的高功率光纤激光器,这些可以很好的覆盖动力电池焊接所需的系列激光器,如下图所示。

In order to be able to solve the problems encountered in power battery welding, Raycus has introduced several small-core fiber lasers suitable for power battery laser welding. Combined with the semiconductor laser for dual laser hybrid welding and high-power fiber laser, it can well cover the needs of power battery welding.

 

500W~1kW

连续光纤激光器

光纤芯径

14μm~50μm

2kW~3kW

连续光纤激光器

光纤芯径

25μm~50μm

1kW~2kW

光纤输出半导体激光器

光纤芯径

300μm~600μm

4kW~6kW

连续光纤激光器

光纤芯径

100μm~200μm

 

 

议程预告

Agenda Preview

 

12月16-18日,“2019高工锂电&电动车年会”在深圳机场凯悦酒店盛大开幕,年会主题为“全球电动化的至暗时刻与远大前程”,一场锂电行业的年度思想盛宴激光上演。

On December 16-18, the "2019 Advanced Lithium Battery & Electric Vehicles Annual Conference" was grandly opened at the Hyatt Regency Shenzhen Airport. An annual ideological feast for the lithium battery industry was staged by laser.

随着激光技术的不断发展和新工艺的开发,将会为锂电领域提供更好的解决方案,锐科激光也将在此次锂电盛宴上分享助力动力电池智能制造的光纤激光器产品和解决方案。

With the continuous development of laser technology and the new processes, it will provide better solutions for the field of lithium battery, Raycus will also share fiber laser products and solutions that the intelligent manufacturing of power batteries at this lithium battery feast.

 

2019 高工锂电&电动车年会

2019 Senior Engineering Lithium & Electric Vehicle Annual Conference

时间:

12月17日(周二)   9:45-10:00

演讲人:

锐科激光 新能源行业总监 童慰

Mr. Tong Wei, The Director of New Energy Industry 

演讲主题:

国产激光器进口替代加速度

The development of Fiber Laser Industry

圆桌对话:

在12月17日(周二)11:30-12:00同期举行的圆桌对话中,锐科激光副总经理李杰将与现场众多精英共同探讨,激光智能制造升级助力动力电池制造降本提效等相关议题。

In a roundtable dialogue held concurrently from 11:30 to 12:00 on December 17th (Tuesday), Mr. Daniel Li, the deputy general manager of Raycus, will discuss with other elites on the topic about laser manufacturing upgrades in power battery industry and other related topics.

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