How to design a battery pack?

 

In today’s world, almost everything we use is powered by batteries. From our cell phones to our electric vehicles, we rely on battery packs to keep us connected and productive. So, how to design a battery pack and made it?

What is the battery pack?

 

When designing a battery pack, there are a few things to consider. The type of battery, the capacity, voltage, and size are all important factors.

 

Battery packs come in all shapes and sizes, but most contain one or more batteries of the same or similar type cells. The capacity of a battery pack is the total amount of energy that can be stored in the batteries it contains. The voltage of a battery pack is the total amount of electrical potential energy that can be generated by the batteries it contains.

 

The size of a battery pack is usually determined by the cell type and number of batteries it contains.

18650,  21700, 26650, 32700 and Prismatic battery cells are some of the most common types used in battery packs. The number of cells in a battery pack also determines its size;

 

 

A Prismatic battery cell is much larger than a 18650 cell.

 

Most battery packs also have a connector that allow them to power electric devices like mobile phones, electric vehicle and floor scrubbers. The type of connector varies depending on the intended use of the battery pack;

 

12V battery packs are commonly used to power appliances in RVs, while 48V battery packs power electric forklifts.

 

 

What do battery packs power?

 

Battery packs mainly provide power to electronic devices. The most common types of battery packs are lithium-ion battery packs NiMH batteries.

 

NiMH batteries are mainly used in consumer electronics such as remote control toys for children, cameras, etc.

Lithium-ion batteries are used in laptops, mobile phones and other portable electronic devices.

 

In addition, lithium batteries are also commonly used in robots, cars, electric forklifts, ships and other devices that require stable power output.

 

Other types of battery packs include alkaline battery packs and lead-acid battery packs. Alkaline battery packs are used in some digital cameras and camcorders. Lead-acid battery packs are used in some car alarm systems and backup power supplies.

 

 

How are battery packs designed?

 

When designing a battery pack, engineers must consider many factors including the type of battery cell, desired capacity, voltage, dimensions, cost, safety requirements, use environment, etc.. The first step is to determine which type of battery will best suit the needs of the device.

 

For example, Lithium-ion batteries are usually used in devices that require stable power, because they have a high energy density and can be recharged many times. Once the type of battery is selected, the next step is to determine the desired capacity in terms of watt-hours (Wh).  This is usually determined by the power requirements of the device and how long it needs to run on a full charge.

 

After capacity is determined, engineers must select an appropriate voltage for the battery pack. This again depends on the needs of the device being powered.

 

 

For example, most mobile phone chargers output 5 volts, so a mobile phone battery pack would need to be designed for 5 volts.

 

Once voltage is selected, engineers can begin to work on dimensional constraints such as length, width, and thickness. These dimensions are often dictated by the available space inside the device.

 

When all these factors have been considered, engineers can begin designing the actual battery pack. This involves choosing an appropriate housing material and layout for all the cells within the pack. The goal is to create a design that is safe, efficient, and meets all the performance requirements set forth at the beginning of the project.

 

 

What factors must be considered when designing a battery pack?

 

When designing a lithium battery pack, there are 11 key factors that must be considered:

 

1. Capacity

The capacity of a battery pack is typically measured in mAh (milliamp hours). This represents the amount of energy that can be stored in the battery, and will determine how long the device can be powered for.

 

2. Voltage

The voltage of a battery pack is also important to consider. Most devices require between 3-72 volts, so the battery pack must be able to provide power at the corresponding voltage.

 

3. Current

The current rating of a battery pack is typically measured in amperes (amps). This represents the amount of current that the battery can provide, and will determine how quickly the device can be powered.

 

4. Charge Time

The charge time of a battery pack is also an important factor to consider. This represents the amount of time it takes to fully charge the battery, and will impact how often the device needs to be plugged in.

 

5. Size & Weight

The size and weight of a battery pack are also important considerations, as this will impact where and how the device can be carried.

 

6. Battery cells selection

Different capacities, types ( 18650, 21700, 26650, 32700, etc.), materials ( LiFePO4,  Li2TiO3,  Li( NiCoMn )O2, etc.), Charge & Discharge multiplier ( 0.1-60C ), etc. need to be fully considered in the design.

 

7. The choice of battery protection plate

Unlike lead-acid batteries, lithium batteries are used in conjunction with the battery cells. The protection board, which can effectively prevent the battery from overcharging and short-circuiting and other fault protection.

 

Protection board is generally PCM (Protection circuit module), PCB (Protection circuit board) and BMS (Battery management system), PCM and PCB can only provide basic battery protection, while the BMS provides communication functions and more intelligent protection, etc.

 

8.Selection of wire harness

Different current and connection methods need to consider the diameter of the harness, length, material, plug type, etc.

 

9. Cost

In the design of the battery pack, different factors such as cells, protection plates, harnesses and structures will have different price combinations, the optimal solution and cost control is also very important.

 

10. Safety standards and norms

Different countries, regions and industries have developed different testing rules, only to meet these rules are allowed to sell and use in the corresponding countries, regions and industries.

 

Common certifications:

• – UN38.3 : ST/SG/AC.10/11/Rev.7/38.3
• – CB : IEC62619
• – CE-EMC : EN61000-6-1; EN61000-6-3
• – EU Battery Directive: 2013/56/EU

View each certification.

 

11.Working environment

 

The working environment of the battery pack is also an important factor to be considered in the design process. For example: temperature, vibration, humidity, dust, etc.

How does the design process work?

 

The design process for a battery pack can be broken down into a few simple steps:

 

• 1. Define the requirements for the battery pack. This includes things like the desired capacity, voltage, size, and weight.

 

• 2. Select the appropriate battery chemistry and cell configuration based on the requirements.

 

• 3. Design the circuit that will connect the cells together in the desired configuration.

 

• 4. Prototype the design and test the parameters of the battery pack to verify that it meets all the requirements.

 

• 5. Make any necessary changes to the design based on feedback from the prototype testing.

 

• 6. Mass manufacture the battery pack according to the finalized design.

 

Conclusion

 

Designing a battery pack is not as difficult as it may seem. With a little planning and creativity, you can design a battery pack that will meet your needs and exceed your expectations.

 

Or,  get in touch with SIXPACK, a professional custom battery pack designer and manufacturer to get more information and support.