Battery Pack Side Cooling or Bottom Cooling, Which Is Better?

Thermal management is a critical cornerstone of battery pack performance, safety, and service life, especially as electric vehicles (EVs) and energy storage systems (ESS) continue to develop towards higher power density, faster charging speeds, and more diverse operating scenarios. The efficient dissipation of heat generated by battery cells during charging and discharging directly determines the stability of energy output, the risk of thermal runaway, and the long-term reliability of the entire battery system. Among the various thermal management technologies currently in practical application, side cooling and bottom cooling are two mature and widely adopted solutions, each with distinct working principles, performance characteristics, and applicable scenarios. This article will systematically compare the two methods in terms of principle, advantages, disadvantages, and application scope, providing a clear reference for the selection of battery pack thermal management solutions.

Liquid cooling plates or heat conduction structures are installed on the sides of the battery pack. Coolant or heat-conducting materials transfer heat generated by cells from the sides, expanding the heat dissipation area and improving cooling efficiency.

It provides a large heat dissipation area and effectively reduces cell surface temperature, making it highly suitable for high-power and high-rate charging and discharging scenarios such as ultra-fast charging battery packs.

It optimizes internal temperature uniformity of the battery pack, minimizes temperature differences between cells, and reduces the risk of thermal runaway.

For both cylindrical and prismatic cells, side cooling enables better coverage of core heat-generating areas.

The structure is relatively complex, requiring strict consideration of liquid cooling plate installation, sealing and close contact with cells, resulting in higher costs.

It occupies lateral space inside the pack, restricting the overall layout design when the battery pack dimension is limited.

Widely adopted in high-end electric vehicles, energy storage systems and other high-power applications, represented by CATL Qilin Battery and some Tesla models.

A liquid cooling plate or heat-conducting base plate is arranged at the bottom of the battery pack. Heat is conducted outwards through direct contact between the bottom structure and cooling media.

It features a simple structure and lower cost, facilitating mass production and standardized manufacturing.

It meets basic heat dissipation demands for low-power and low-rate operating conditions with minimal space occupation.

The limited heat exchange area leads to low cooling efficiency, failing to support high-power operation and high-rate fast charging.

It easily causes uneven internal temperature distribution; the bottom remains cool while heat accumulates at the top, impairing overall battery performance and service life.

Applied to low-power devices, entry-level electric vehicles and battery packs with low heat dissipation requirements, including cost-effective EVs and general energy storage battery modules.

Side cooling delivers high cooling efficiency and superior temperature consistency, ideal for high-power and high-rate working conditions at a higher structural cost. Bottom cooling boasts a simple structure and cost advantages, which is applicable to low-power and low-demand scenarios. In practical engineering, hybrid solutions combining side cooling and bottom cooling are commonly adopted to achieve comprehensive thermal management performance.

In the global transition towards green energy and carbon neutrality, electric vehicles (EVs) and energy storage systems (ESS) have become the core driving forces of the new energy revolution. Among the key components that determine the performance, safety, and lifespan of EV battery packs and ESS modules, thermal management systems stand out as a critical technology—directly affecting charging efficiency, battery cycle life, and even preventing thermal runaway risks. Trumony Aluminum Limited (referred to as "Trumony"), founded in 2017 and headquartered in Suzhou, Jiangsu Province, China, has emerged as a fast-growing, innovative manufacturer and one-stop solution provider specializing in high-performance battery thermal management systems, liquid cooling solutions, and aluminum heat exchangers, dedicated to supporting the global new energy industry with reliable, cost-effective, and customized thermal management technologies.

Whether you are an EV OEM, battery manufacturer, ESS integrator, or enterprise in need of high-quality battery thermal management solutions, Trumony is your reliable long-term partner. We are committed to strengthening cooperation with global partners, jointly promoting the development of the new energy industry, and achieving win-win results. If you are interested in our side cooling, bottom cooling, or integrated liquid cooling solutions, want to customize thermal management products for your specific needs, or have any questions about our products and services, please do not hesitate to contact us immediately—our professional team will respond to you promptly and provide you with tailored solutions.

• Headquarters Address: Jindi Weixin Wuzhong Intelligent Manufacturing Park, Wuzhong District, Suzhou City, Jiangsu Province, China

• Factory Address: Suqian Economic & Technological Development Zone, Jiangsu Province, China

• Email:sales4@trumony.com

Contact Trumony today, and let us work together to create a greener, more sustainable future with advanced battery thermal management technology!