According to BatteryDesign, a platform specializing in publishing and developing scientific research in the automotive battery industry, the Cell to Pack initiative proposed by CATL and BYD to directly integrate cells into battery packs has been elucidated and clarified. This initiative primarily aims to showcase the current battery technologies, explore their drawbacks and advantages, and investigate how to achieve a balance between cost and energy efficiency in both manufacturing and usage.

These proposals were detailed on the official platform website on June 23, 2023, by Nigel Taylor, a physicist and a member of the Scientific Advisory Board and the official founder of BatteryDesign. This comes after a recent surge in battery pack designs and modifications by manufacturers worldwide, particularly those introduced by BYD and CATL. While BYD introduced its innovative "Blade" design, notable for its use of the modern LFP chemistry for electric vehicle energy supply, there remains much data to be analyzed and researched for future improvements.

The "Cell to Pack" initiative focuses on cost reduction and increasing the volumetric density of battery packs to accommodate and provide more energy efficiently. This, in turn, is expected to impact global electric vehicle prices and post-purchase maintenance costs positively. Moreover, it seeks to design vehicle batteries in a holistic manner after rigorous experiments by experts and researchers worldwide to achieve a significant increase in energy density while reducing costs.

However, this will require eliminating barriers between internal battery cells and integrating them seamlessly into the vehicle's body to ensure safety and sustainability. This effort will necessitate intensified research to understand how to prevent cell dispersion within the entire battery pack, thereby avoiding potential risks and problems within the battery's internal structure, which would ultimately impact passenger safety.

As a first step, CATL and BYD suggest placing cells directly into the battery pack to achieve an approximate increase of >250 W/kg in energy density. CATL also aims to achieve the following benefits:

1. Increase in battery pack volume utilization by 20-30%.

2. Reduction of the number of components in the battery pack by 40%.

3. A 50% increase in production efficiency.

Indeed, CATL has achieved these claims with the introduction of the next-generation cell design for the Qilin pack. It incorporates prismatic cells with flexible cooling plates between the cells.

CATL has further noted that this integrated system can increase energy density to 255 W/kg for three-system battery packs (NMC, NMCX, etc.) and 160 W/kg for LFP battery systems. This represents a significant change in energy density.

However, challenges remain, such as maintaining an adequate cooling system. The cooling plates are compressed by the cells even during expansion, ensuring that the cells continue to expand throughout the pack's lifespan.

From a neutral standpoint, this means that cooling channel width will decrease as the cells age and expand, restricting coolant flow. Additionally, as cells age, internal resistance will increase, leading to higher temperatures during use. Elevated temperatures can result in faster cell degradation.

Regarding the cooling system, each cooling plate has specialized terminal connectors, increasing the likelihood of potential future leaks, which could have negative and hazardous consequences.

Safety is a paramount concern in battery design. Traditional spacing between cells and module units is considered unsafe for managing cell dispersion. Additionally, lithium iron phosphate (LFP) is a more stable compound in such scenarios.

Mechanical Distribution: Structural bundles within the battery pack help manage collision loads, package durability, and vehicle durability. However, how these will be distributed in the future remains a question.

Maintenance: Typically, individual cells or modules can be replaced if a fault occurs. Will this transition to a service pack replacement, and what will be the cost and environmental impact?

Due to these possibilities and concerns, the Blade design introduced by BYD has received significant attention and was described by Wang Chuanfu, Chairman of BYD, as a solution to battery safety issues, redefining safety standards for the entire industry.

The design of the BYD Blade pack is groundbreaking and may have lower manufacturing costs compared to other designs. During testing, no smoke or fire was emitted from the battery, even after penetration. Its surface temperature reached only 30 to 60 degrees Celsius under the same conditions. In contrast, a traditional lithium iron phosphate battery exceeded 500 degrees Celsius and burned vigorously under similar conditions. While no open flames or smoke were emitted from a conventional lithium iron phosphate battery, its surface temperature reached dangerously high temperatures ranging from 200 to 400 degrees Celsius. This means that electric vehicles equipped with Blade batteries are less prone to ignition, even under severe damage conditions.

Furthermore, Blade batteries have successfully undergone other rigorous tests, including crushing, bending, heating to 300 degrees Celsius in an oven, and overcharging by 260%. None of these tests resulted in a fire or explosion.

In conclusion, the Blade design addresses various concerns and requirements that were previously lacking in the Qilin design, producing remarkable results. These include higher efficiency, improved aerodynamics, increased structural strength, better body rigidity, efficient use of space, and effective mechanical distribution.

This raises key questions about the future of this design, especially the Blade design:

1. When will vehicle structure repairs and modifications begin?

2. How will the top cover of the battery be sealed to the structure?

3. How will battery sealing be facilitated?

4. Will the electric mass be separated from the structure upon removal?

5. How will recycling of this pack be facilitated?