Battery system capable of controlling internal battery module conditions and its control method

Battery system that maintains constant swelling pressure through complementary charge/discharge control of auxiliary cells

This technology uses sensors to detect pressure changes caused by the expansion or contraction of primary cells (first cells) during charge and discharge cycles, and complementarily adjusts the charge/discharge state of auxiliary cells (second cells) to maintain constant mechanical pressure within the module.

Swelling during the charge/discharge process of secondary batteries increases internal module pressure. This elevated pressure leads to performance degradation and shortened lifespan, including structural changes in anode materials, SEI layer formation, and lithium plating.

The battery management module compares sensor-input pressure values against a reference to calculate the difference, then uses a lookup table to determine the optimal charge or discharge current for the second cell. When the first cell expands, the second cell is discharged to reduce volume; when the first cell contracts, the second cell is charged to increase volume, keeping overall module pressure uniform. Applicable to EV battery modules, ESS racks with stacked pouch cells, and solid-state modules where pressure management is critical, this technology reduces the need for mechanical pressurization structures while actively preventing pressure-related degradation like lithium plating.

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Key Features:

• A battery module comprising first and second cells that change state during charge/discharge, and a sensor that detects the force exerted by the state change of the first cell
• A battery management module that determines the difference between the current value generated by the sensor and a preset reference, and uses a first lookup table to determine the charge or discharge current for the second cell
• A controller that determines first electrical information regarding available current using second electrical information generated from power information stored in the second cell and a second lookup table
• A bidirectional power supply that supplies charge current to or receives discharge current from the second cell according to control signals from the controller

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This invention was developed with support from the Ministry of Science and ICT for the development of impedance management and lifespan enhancement technology for electric vehicle lithium-ion batteries using low- and high-frequency synthetic surface pressure excitation.

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