Low temperature charging of Li-ion cells
AssigneeTesla Motors, Inc.
InventorAnil Paryani
Life of this patent
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Abstract
A battery cell charging system, including a charger and a controller, for low-temperature (below about zero degrees Celsius) charging a lithium ion battery cell, the battery cell charging system includes: a circuit for charging the battery cell using an adjustable voltage charging-profile to apply a charging voltage and a charging current to the battery cell wherein the adjustable voltage charging-profile having: a non-low-temperature charging stage for charging the battery cell using a charging profile adapted for battery cell temperatures above about zero degrees Celsius; and a low-temperature charging stage with a variable low-temperature stage charging current that decreases responsive to a battery cell temperature falling below zero degrees Celsius.
Claims16
A charging system, comprising:
- a lithium ion energy storage element;
- a charger;
- and
- a battery management system that (i) determines when the lithium ion energy storage element has a temperature below 32 degrees Fahrenheit, and (ii) in response to the determination, applies a charging profile that sets a temperature-dependent current limit and a temperature-dependent voltage limit for the charger, wherein when the lithium ion energy storage element does not have the temperature below 32 degrees Fahrenheit, the battery management system applies a temperature-independent current limit, at least up to a maximum temperature, and a temperature-independent voltage limit.
A charging method, comprising:
- determining when a lithium ion energy storage element in a charging system has a temperature below 32 degrees Fahrenheit;
- in response to the determination, applying a charging profile that sets a temperature-dependent current limit and a temperature-dependent voltage limit for a charger of the charging system;
- and
- when the lithium ion energy storage element does not have the temperature below 32 degrees Fahrenheit, applying a temperature-independent current limit, at least up to a maximum temperature, and a temperature-independent voltage limit.
Dependencies are inferred from the claim text.