Semco university – All about the Lithium-Ion Batteries


About the Battery Module and Pack – Semco university


Battery is a generic term for battery cell, battery module and pack. All are different forms of batteries in different stages of application. The smallest of these units is the battery cell, several cells can form a module, several modules can form a battery pack by adding BMS and other management systems.

The Shape of the Power Cell

Square Cells (Steel Shell / Aluminum Shell Battery )
Square Cells (Plastic Shell Battery)
Soft – Packed Cells
Cylindrical Cells

Group of Square Power Cells                          

Soft package power cells in groups

Soft package power cells in groups

Cylindrical power cells in groups

Group of power cells

Battery Box 1

Battery Box 2

Battery Box 3

Tesla Battery Box

Exploded View of Square Module

Exploded View of Soft Package Module

Bolting and Welding

Contact Resistance: The resistance presented between conductors is called contact resistance.

1. Concentrated Resistance: The resistance shown by contraction (or concentration) of the current line when the current passes through the actual contact surface.

2. Film Resistance: Film resistance due to contact surface film and other contaminants.

Factors affecting contact resistance:

1. Contact Material,
2. positive pressure,
3. surface condition,
4. Use Voltage,
5. Current


1. Simple and convenient connection, low cost.
2. Easy to assemble and disassemble for maintenance

Requirements for bolted connections:

1. Surface finish,
2. Certain Preload,
3. Surface needs to be coated


1. The surface is prone to corrosion,
2. Due to relationship between the preload and the surface quality, the contact resistance is unstable,
3. After vibration, it is easy to cause the bolt to loosen, and the contact resistance increases

Resistance Spot Welding and Laser Welding

Resistance Welding: After the work piece is assembled, pressure is applied through the electrode, and the electric current is passed through the contract surface of the joint and the resistance heat generated by the adjacent area for welding.
Laser Welding The surface to be processed is heated by laser radiation, and the surface heat diffuses into the interior through thermal Battery Laser Welder conduction. By controlling the laser parameters such as width, energy, peak power and repetition frequency of the laser pulse, the workpiece is melted to form a specific molten pool.

Resistance Spot Welding and Laser Welding

Advantages of Resistance Spot Welding Machine:

1. The production cost is low, and no other consumables are required.

2. Welding time is short, forming faster.

Disadvantages of Resistance but Welding Machine:

1. A large of electric sparks will be generated during the welding process, the safety is not high, and it needs to be isolated.

2. Since isolation is required during the welding process, the entire welding process cannot be observed at close range, the controllability of the process is low.

3. The automation degree of the equipment is high, so the cost of the equipment is high and the maintenance cost is high.

Buy Now: Semco Double Side Automatic Spot Welding Machine – SI DSWM 8X 8000A

Advantages of Laser Welding Machine:

1. Small thermal impact, because the laser is highly condensed into extremely small spots, so its thermal impact is small, as it will basically not affect the original performance of the workpiece after welding.

2. Energy saving and environmental protection, it is beneficial to keep the workplace clean and protect the health of operators.

3. The production cost is low, and the laser can be used for a long time only after filling the laser once.

4. Adjustable light point, can achieve precise welding.

5. The electro-optical conversion rate is high, which is conducive to saving production costs.

6. The welding speed is fast, which is several times that of traditional welding equipment.

7. It can be observed at a close distance, and the controllability of the product process is strong.

8. The welding surface is flat, the bonding force is strong, the welding depth is deep, and the welding seam is narrow.

Disadvantages of Laser Welding Machine:

  1. The position of the weldment must be very precise and must be within the focus range of the laser beam.
  2. When a fixture needs to be used for the weldment, it must be ensured that the final position of the weldment is aligned with the welding point that the laser beam will strike.

The maximum weldable thickness is limited by the penetration thickness far exceeding19mm the workplace is not suitable for laser welding on the production line. High reflectivity and high thermal conductivity materials such as aluminum, copper and their alloys etc. the weldability will be changed by the Laser.

Buy Now: Semco Single Side Automatic Spot Welding Machine – Pnuematic SI SSWM 3X 5000A

Ultrasonic Welding

Principle: The principle of ultrasonic metal welding is to use ultrasonic frequencies (more than16KHz) of mechanical vibration energy, a special method for connecting the same metal or dissimilar metals. When the metal is ultrasonically welded, it neither transmits current to the workpiece nor applies a high temperature heat source to the workpiece, but under static pressure, the frame vibration energy is converted into friction work, deformation energy and limited temperature rise between the workpieces. The metallurgical bond between the joints is a solid-state welding realized without the base metal melting. Therefore, it effectively overcomes the phenomenon of spatter and oxidation during resistance welding. Ultrasonic metal welding machine can perform single-point welding, multi-point welding and short-strip welding of copper, silver, aluminum, nickel and other non-ferrous metal filaments or sheet materials.

Advantages of Ultrasonic Metal Welding:

1.The welding material does not melt, and the metal characteristics are not fragile.

2.Good conductivity after welding, and the resistivity is extremely low or close to zero.

3.Low requirements for welding metal surface, can be welded by oxidation or electroplating.

4.Short soldering time, no need for any flux, gas, solder.

5.Welding without sparks, environmental protection and safety.

Applicable Products

1. Nickel-metal hydride battery, nickel-metal hydride battery, nickel mesh and nickel sheets are mutually fused and nickel sheets are mutually fused.

2. lithium battery, polymer battery copper foil and nickel fusing, aluminium foil and aluminium fusing each other.

3. The wires are fused to each other, and the partial knot is formed into one and several fused to each other.

4. Wires and various electronic components, contacts and connectors are mutually fused. Various household appliances, large – scale heat sinks for automotive supplies, heat exchange fins, and honeycomb cores.

5. Various household appliances, large-scale heat sinks for automotive supplies, heat exchange fins, and honeycomb cores, electromagnetic switches, non-fuse switches and other high current contacts, mutual fusion of dissimilar metal sheets.

Significance and Status Quo of Research on Battery Thermal Management System

The cost, performance and life of the power battery are largely determined by HEV cost and reliability. The temperature of the battery and the uniformity of the temperature field    have a great influence on the performance and life of the battery.

Therefore, it is of great practical significance to optimize the design of the battery heat dissipation structure and predict the heat dissipation performance for improving the maturity and reliability of hybrid electric vehicles and power batteries.

Battery Thermal Management

There is no thermal management system, that is, the battery is not deliberately cooled, and the natural cooling method is adopted, such as Leaf electric car.

Adopting Air Cooling: There are mainly cooling and cooling through the internal circulation of the battery pack and cooling through external fan ventilation, of which the former accounts for the majority and the latter is relatively small. Water cooling or other liquid medium cooling

Air Cooling System: Adjust the fan speed in monitoring point real time through the temperature of the temperature.

Battery Thermal Management: A Sample Battery pack optimization scheme 1 (change the title angle and the spacing of the batteries)

Battery Thermal Management

A sample battery pack optimization plan 2 (battery position does not move, add baffle)


Lithium Ion and Lithium-Ion Polymer batteries are a great power source for projects but they require care during use and charging. They can be easy to damage or misuse and can hurt you or your property! All the batteries we sell pass testing and certification but you should still be careful with them. Read the datasheet, follow our suggestions and those in the datasheet as well as common sense!

More Articles:

BMS Battery Management System,
Lithium ion battery fire accidents occur frequently, what is the reason?,
Introduction to Cell Balancing System,
IEC Battery Safety Standard for Power Batteries,

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