Life-extending recharge control for cold weather lithium-ion power supplies

A rechargeable lithium-ion battery assembly comprising:

• an enclosure sized and shaped to operatively fit within a battery compartment of a vehicle;
• a positive terminal and a negative terminal disposed to be connected to wiring from an outside of the enclosure;
• a plurality of battery cells disposed within the enclosure and interconnected with the positive and negative terminals to provide a combined electrical potential between the positive and negative terminals, where each battery cell of the plurality of battery cells is a lithium-ion battery cell;
• and
• a printed circuit board assembly (PCB) disposed in an orientation relative to a first array of battery cells of the plurality of battery cells within the enclosure such that a first end of each of the battery cells of the first array of battery cells is adjacent the PCBA, the PCBA comprising:
• a collector plate electrically coupled with each battery cell of the first array of battery cells,
• a temperature sensor configured to obtain temperature readings and disposed on a first surface of the collector plate facing the first array of battery cells,
• a plurality of heaters configured to generate heat using electrical power and disposed on the first surface of the collector plate, and
• an assembly processor configured to:
• obtain temperature readings from the temperature sensor,
• determine an estimated battery cell temperature of the plurality of lithium-ion battery cells based on the obtained temperature readings, and
• in response to determining that the estimated battery cell temperature is less than a predetermined threshold temperature, initiate a heating program by delivering electrical power to the plurality of heaters from an electrical power source to enable the plurality of heaters to generate heat.

A method of charging a plurality of lithium-ion battery cells of a battery assembly, the method comprising:

• coupling a power source configured to charge the plurality of lithium-ion battery cells to the battery assembly;
• calculating, using a processor of the battery assembly, an estimated temperature of the plurality of battery of cells using temperature readings from a temperature sensor of a printed circuit board assembly (PCBA) of the battery assembly adjacent to the plurality of lithium-ion battery cells;
• comparing, using the processor, the estimated temperature of the plurality of battery cells to a threshold temperature value;
• in response to determining that the estimated temperature of the plurality of battery cells is greater than the threshold temperature value, initiating a charging program, by the processor, to deliver electrical power from the power source to the plurality of lithium-ion battery cells for charging;
• and
• in response to determining that the estimated temperature of the plurality of battery cells is less than the threshold temperature value:
• initiating a heating program, by the processor, in which the processor delivers the electrical power from the power source to a plurality of heaters disposed on the PCBA to raise the temperature of the plurality of cells,
• calculating during the heating program, by the processor, the estimated temperature of the plurality of the battery of cells using temperature readings from the temperature sensor, and
• comparing, by the processor, the estimated temperature of the plurality of battery cells calculated during the heating program to the threshold temperature value,
• in response to determining that the estimated temperature of the plurality of battery of cells calculated during the heating program is greater than predetermined threshold temperature value, ending the heating program and initiating the charging program, by the processor, to deliver the electrical power from the power source to the plurality of battery cells for charging.