Preparation before spot welding

Before spot welding the 18650 battery, proper preparation is key to ensuring weld quality. Firstly, cleaning and deburring the battery is a step that cannot be ignored. These impurities can affect the welding effect, as grease and oxides can remain on the battery surface. It is recommended to use an alcohol cotton pad to gently wipe the positive and negative electrodes of the battery, keeping the surface clean and stain-free. If the battery pole has burrs, you can use fine sandpaper (400 mesh or more) to lightly sand it, but be careful not to over-polish it that can cause the pole to become thinner.

Secondly, the setting of the spot welder is a crucial factor affecting the weld quality. The voltage and pulse time should be adjusted according to the thickness of the nickel sheet and the type of battery. In general, it is recommended to use 3.5V with a pulse time of 5ms for nickel sheets with a thickness of 0.15mm, while nickel sheets with a thickness of 0.2mm need to be increased to 4V, and the pulse time is extended to 7ms. According to data from a battery manufacturing plant in Hong Kong, improper parameter settings can lead to a weld defect rate of up to 30%.

When it comes to tool preparation, the choice of nickel sheet is just as important as the quality of the spot welding pen. The nickel sheet must be made of materials with a purity of at least 99% to ensure electrical conductivity and weld strength. For spot welding pens, it is recommended to choose models with copper nibs, as they have excellent thermal conductivity and durability. Here is a list of common tools:

• Nickel sheet (0.15mm/0.2mm thickness)
• Spot welding pen (copper nib)
• Insulating tape
• Alcohol Cotton Pad
• Fine sandpaper (400 mesh or more)

Basic Principles of Spot Welding

The core principle of spot welding is the resistive thermal effect, that is, the localized high heat is generated by a large current in a short time, and the nickel sheet and battery electrode are fused. When an electric current flows through the contact point between the nickel sheet and the battery electrode, a large amount of thermal energy is generated due to the presence of contact resistance, causing the metals to fuse together. This method has a smaller heat-affected zone than traditional welding, effectively protecting the integrity of the body.

The spot welding process can be divided into three stages: pre-pressing, welding, and retention. During the pre-press stage, a slight pressure is applied to the nickel sheet through a spot welding pen to ensure good contact. It energizes the welding stage to generate high heat. The holding stage maintains pressure even after the power supply is cut off, allowing the molten metal to cool and solidify. According to the technical manual, time management at each stage is very important, especially the welding stage is too short, leading to welding defects, and too long will damage the battery.

Specific Steps for Spot Welding

Cutting and positioning the nickel sheet is the first step in spot welding. The nickel sheet should be cut to the appropriate width (usually 5-8mm) and ensure it is long enough to cover the battery electrodes. When positioning, it is necessary to ensure that the nickel sheet is in full contact with the battery electrodes without any gaps. When using multiple layers of nickel sheets, it is recommended to spot weld the bottom layer first and then layer on top of it to reduce heat buildup.

Proper use of spot welding pens is key to ensuring weld quality. The nib should be held securely and the nib should be perpendicular to the battery surface to avoid tilting or uneven welding. The intensity and time control of spot welding should be adjusted according to the thickness of the nickel sheet, generally 2-3kg is recommended, and the time should be controlled to 5-10ms. According to measurement data from a maintenance workshop in Hong Kong, insufficient strength can reduce welding strength by more than 40%.

Attention should also be paid to the placement of the spot weld joints. To distribute stress and improve overall strength, it is recommended to use a staggered arrangement where adjacent solder joints are not on the same straight line. Each cell electrode should have at least 3-4 solder joints, and the solder joint spacing should be constant (about 5mm). Here are some common solder joint placement patterns:

Common spot welding problems and solutions

Weak point welding is the most common problem encountered by beginners, mainly due to improper parameter settings and contamination of the nickel sheet surface. The solution is to re-clean the nickel and battery electrodes and adjust the voltage and pulse time of the spot welding machine. If the problem persists, try increasing the number of solder joints or switching to a thicker nickel sheet.

Overheating of the battery can cause damage, causing security issues. During the spot welding process, it is recommended to leave an interval of 10-15 seconds to allow the battery to dissipate heat.18650 スポット溶接機If you frequently overheat during use, you can check if the cooling system of the spot welder is working properly.

Nickel burnthrough is usually caused by too long a pulse time or too high a current. The solution is to reduce the voltage or shorten the pulse time and ensure that the spot weld tip is clean and free of oxidation. Spot welding machine failures can be caused by unstable power supplies or aging internal components, so regular maintenance and the use of a stabilized power supply are recommended.リチウムイオン電池 構造

Inspection and maintenance after spot welding

Spot weld hardness testing is the final step to ensure weld quality. Use tweezers to gently pull on the nickel sheet and observe for any looseness. If the solder joint falls off easily, it will need to be spot welded again. In addition, a multimeter can be used to measure the resistance between solder joints, and the normal value should be less than 10 mΩ.

Battery protection is equally important. After spot welding, it is recommended to cover the solder joints with insulating tape to avoid short circuits. For long-term storage, the battery should be placed in a dry environment and the solder joints should be checked regularly for oxidation.

Advanced skills: multi-layer nickel sheet spot welding, special material spot welding

Multilayer nickel spot welding should be done in layers, and each layer should be cooled after welding before moving on to the next layer. Spot welding of special materials (for example, nickel-plated steel strips) requires adjustment of parameters, usually increasing the voltage by 10-15%. Tests from Hong Kong suppliers have shown that the optimal welding parameters for nickel-plated steel strips are 4.5V voltage and 8ms pulse time.

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In the era of credit card popularization, the importance of fees

In today's society, credit cards have become one of the mainstream payment methods for consumers. According to the Hong Kong Monetary Authority, the total credit card transaction value in Hong Kong exceeded HK$1.2 trillion in 2022, with an annual growth rate of 8.5%. The popularity of this payment method has not only changed consumer shopping habits but has also significantly impacted the business model of merchants.

For merchants, accepting credit card payments can improve customer satisfaction and sales, but the associated fees cannot be ignored. A seemingly simple card transaction involves the distribution of profits from multiple parties, such as the issuing bank, acquirer, or credit card organization, and these costs are ultimately passed on to the merchant in the form of a commission.

For consumers, in most cases, there is no direct payment of card fees, but these costs are actually indirectly reflected in the price of the goods. Please note that certain special transactions, such as international consumption or cash advances, may require consumers to bear additional fees. Therefore, it is particularly important for both merchants and consumers to understand the operational mechanism of credit card fees.

Composition and calculation method of credit card machine handling fee

Credit card transaction fees mainly consist of three parts: issuer fees, acquirer fees, and credit card organization fees. In the Hong Kong market, the distribution ratio of these three is roughly as follows:

• Issuer fee: about 60-70% of the total fee
• Acquisition fee: about 20-30%
• Credit card mixing fee: about 10-15%

The commission formula is typically the commission rate × the transaction amount. The average commission rate in the Hong Kong market is around 1.5%-3%, depending on the type of credit card.信用卡機比較

In addition, some credit card machine companies charge additional fees such as monthly fees, transaction fees, and equipment rental fees in addition to the basic fee, so merchants need to consider comprehensively when choosing a credit card machine.

How do merchants choose the right credit card machine and reduce fees?

When proceeding, sellers should choose the appropriate equipment type according to their business needs. Currently, there are mainly the following types on the market:

• Traditional stationary card reader: Suitable for physical stores, high stability but poor mobility
• Mobile Payment Terminals: Can be used on smartphones, suitable for couriers and market stalls
• Integrated POS System: Combines cash register and card swipe functionality, suitable for medium and large retailers
• Virtual Credit Card Machine: Pure software solution suitable for e-commerce platforms

To reduce commission costs, sellers can employ the following strategies:

1.Negotiating with multiple acquirers: The Hong Kong market is highly competitive, and merchants with a monthly trading volume of more than HK$100,000 typically receive a fee discount of 0.2%-0.5%.

2.Choose the best billing model: Some providers offer tiered fees, with lower fees for higher trading volumes.

3.Legally pass on some of the costs: In Hong Kong, merchants can charge an additional fee of HK$1 to HK$2 for transactions under HK$100, but they must be clearly indicated in advance and informed to consumers.

How can consumers use credit cards wisely to avoid unnecessary fees?

While there are no direct charges for most daily consumption, consumers should be aware of the following:

Choose an expensive credit card: Some credit cards in Hong Kong offer cash rebates of up to 3-5%, which can effectively offset the costs passed on by merchants. For example, some supermarket-affiliated cards offer a 4% rebate on purchases made at select merchants.

Avoid high-cost transactions: The cash advance fee is usually up to 3-5% of the transaction amount, and the interest is calculated from the withdrawal date. The interest rate for installments is zero, but in most cases there is a commission of 1-3%.

Precautions for overseas consumption: In addition to the 1.95% foreign currency transaction fee, some banks also charge additional service fees. It is recommended to use a dedicated travel credit card, such as those offered by some banks that do not charge foreign currency transaction fees.

Common problems and myths solved

Myth 1: Cash transactions should be cheaper than swiping a card信用卡机

In fact, cash transactions also have hidden costs such as storage risk, change time, etc. For merchants, accepting credit cards can reduce the risk of counterfeit banknotes and improve transaction efficiency. For consumers, the consumer protections and benefits offered by credit cards can often offset the cost of fees.

Myth 2: Fees are the same for all credit card machines

In fact, depending on the type of credit card machine, the difference in fees can be as high as 0.5% to 1%. Mobile payment terminals typically offer a discount of around 0.3% compared to traditional card machines due to their lower cost. Sellers should do this regularly to ensure they use the most cost-effective option.

Precautions for swiping overseas cards

Hong Kong consumers often encounter dynamic currency conversion (DCC) traps when swiping cards abroad, with additional charges of up to 5%. It is recommended to settle in your local currency and ask your bank to exchange money after returning to Hong Kong.

Acquire price knowledge, use wisely, and be conscious of your budget

Credit card fees may seem complex, but mastering the basic principles can help both merchants and consumers make the most favorable choices. For merchants, regular negotiations and rate negotiations are important ways to manage costs. For consumers, understanding the fee structures and rewards plans of different credit cards can help maximize profits.

As payment technology continues to evolve, so too will the fee structure for credit cards. It is recommended that all parties pay attention to industry trends, adjust strategies in a timely manner, and strike an optimal balance between convenience and cost.

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