EV battery module Benefits and Specifications

AIM : To study the benefits of using Battery modules and specifications of an individual module specified for an battery pack.

INTRODUCTION :

A battery is a device that converts chemical energy into electrical energy and vice versa.

The composition of an EV battery might vary slightly depending on the types of electric vehicles, but generally EV batteries are composed of cells, modules and a pack. A number of cells make up a module and a cluster of modules make up a pack. Ultimately, in an EV, one form of battery is installed i.e. a pack.

Importance :

• Battery pack plays a important role for the Electric vehicle in terms of e-mobility.The most common battery type in modern electric vehicles are lithium-ion and lithium polymer, because of their high energy density compared to their weight.
• For EV especially, we must source out energy-dense batteries, means they need to be lightweight and compact at high storage capacity. EV batteries must perform well in high and low temperatures, and be durable enough to be able to match ICE (internal combustion engine) vehicles in terms of longevity and cost. 

Advantages of Battery Module :

• A module consists of several cells generally connected in either series or parallel. A battery pack is then assembled by connecting these modules together, again either in series or parallel.

                                                                         The above image shows the TESLA model single battery module.

There are many advantages of using battery module in a pack such as,

1. Battery modules can be easily replaceable instead of a whole battery pack when there is a failure for some cells or damaged cluster of cells.
2. As each group of cells are connected in a number of different modules thus, it results is an even temperature distribution and hence, effective cooling is guaranteed.
3. Modules are easily detachable, therefore it is easy to maintain and has good serviceability.
4. Due to effective cooling, thermal hotspots are minimized which gives us the higher battery pack life.
5. Battery modules provides better performance and safety if managed properly by BMS.
6. Overall module designs are more reliable and optimum for a battery pack.

Specification of an Individual Battery module :

When designing a battery pack the specific application will dictate the required voltage and current. Individual cells can be scaled up and down and used in different combinations to create output voltages and currents that meet the needs of the application. 

• Individual battery modules are specified mainly on the basis of capacity, voltage range, weight and overall dimensions.
• Operating temperature for charge and discharge, then continuous and peak power, specific energy density, etc is specified for an individual battery module.
• The BMS is also considered mostly for an individual battery module.
• The below images shows the specifications of the battery module used for an EV.

Conclusion :

Thus, we had understood the construction of a battery pack which indicates the main advantages of using modules in a battery pack. In short battery modules in a pack are more reliable, robust and easily maintainable which also gives better battery pack life.

On the other hand, we had studied and understood the specifications for an individual battery module specified as per it’s usage for an EV. There are no. of parameters considered for an individual module selection but, mostly focus is on operating temperature, capacity, overall dimensions, weight, BMS and even charging cycles.

References :

1. https://www.energy.gov/sites/prod/files/2014/05/f15/APR13_Energy_Storage_e_IV_Battery_Tstg_Design_2.pdf
2. https://cdn.borgwarner.com/docs/default-source/default-document-library/battery-module-product-sheet.pdf?sfvrsn=acdd823c_6
3. http://media3.ev-tv.me/TeslaModuleController.pdf