Apple Inc.

A123 Systems LLC

Jinjun Shi

Qingzhi Guo

Loren L Roy

Hyungook Yoon

Premanand Ramadass

Dapeng Wang

Pu Zhang

Viet H Vu

Norberto N Ison

Battery packs having jelly roll battery cells of different capacities may have an imbalance in the charging and/or discharging current supplied to and provided by each jelly roll due to differences in capacity specific impedance between the battery cells of the battery pack. A C-rate (i.e., current relative to rated capacity) of a lower capacity first battery cell and a higher capacity second battery cell connected in parallel may be balanced by repositioning and/or increasing the number of cathode tabs and anode tabs of the second jelly roll battery cell to reduce an impedance of the second battery cell.

Method for balancing a C-Rate of battery jelly rolls of different capacities

A battery system includes a battery cell, a thermoelectric cooler (TEC) that cools the battery cell, a temperature sensor that detects a temperature of the battery cell, and a battery management unit (BMU) controller. The BMU controller activates the TEC to cool the battery cell in response to determining that a state of charge (SOC) of the battery cell is greater than a threshold SOC and the temperature of the battery cell is greater than a threshold temperature.

System and method for cooling battery cells

Battery packs having jelly roll battery cells of different designs or capacities may have an imbalance in the charging and/or discharging current supplied to and provided by each jelly roll due to differences in capacity specific impedance between the battery cells of the battery pack. A C-rate (i.e., current relative to rated capacity) of a first and second battery cell connected in parallel may be balanced by altering properties of an active layer and/or a thickness of a current collector of the second battery cell to reduce an impedance of the second battery cell.

Asymmetric battery pack with varied electrode and current collector properties to achieve C-Rate balancing

Asymmetric battery pack utilizing C-Rate balancing

Battery packs according to embodiments of the present technology may include a first battery cell including a lithium-containing material. The first battery cell may be configured to operate in a voltage window extending to or above about 4 V. The battery packs may include a second battery cell electrically coupled in parallel with the first battery cell. The second battery cell may be configured to operate in a voltage window maintained at or below about 4.0 V. The battery packs may also include a controller configured to receive a measured terminal voltage from the first battery cell. The controller may be configured to determine whether to disconnect the second battery cell from the first battery cell based on the measured terminal voltage of the first battery cell.

Multi-cell battery pack

A material suitable for use in an electrode, preferably an anode, and processes of its formation are provided. The material includes an electrode base material and an organic artificial solid electrolyte interface material including a water soluble organic polymer coating the electrode base material. The polymer is polymerized with a crosslinker to form the organic artificial solid electrolyte interface material. The resulting artificial SEI coated electrode material demonstrates superior discharge rate capacity and cycle stability.

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San Jose, CA, United States of America

Jinjun Shi