Tesla filed patent 'Arc fault detection for battery packs in energy generation systems'

Featured image: Tesla

In recent years, climate change concerns, reduction in costs, governmental initiatives, and other factors have driven a rapid rise in the adoption of distributed renewable energy generation systems (ie, systems that generate energy using renewable resources such as solar, wind, fuel cells, geothermal, etc.) at residential and non-residential sites. Solar energy generation systems, in particular, have become very popular due to numerous advantages over other renewable and non-renewable energy sources.

Solar energy generation systems include photovoltaic (PV) modules that generate power from the sun and can provide the generated power to a utility grid or to one or more onsite loads. Some PV energy generation systems can even store energy from the PV modules and/or utility grid in a battery for future use, such as when the PV modules are not generating power and/or when the AC grid is unavailable. Tesla has a number of products that are aimed at performing these functions.

Source: Tesla

Such PV systems often comprise numerous components that interact with one another to provide usable power from the sun. These components can be damaged during manufacturing or transportation/distribution, or even be improperly installed, which can result in electrical discontinuities that can immediately cause, or build up over time, a thermal event such as arcing.

Arcing is an electrical discharge of current through a normally non-conductive medium (e.g., air). The occurrence of such a thermal event can result in damage to one or more electrical components of the energy generation system if the thermal event is not addressed immediately. Because of the relatively high concentration of individual batteries, high resultant current, and potential for thermal runaway, it is particularly important to guard against arc faults in onsite energy storage devices. Consequently, improvements to the mitigation of damage caused by thermal events are needed.

Tesla filed patent 'Arc fault detection for battery packs in energy generation systems'

Patent filing date: February 20, 2020
Patent publication date: July 23, 2020

A simplified diagram illustrating an exemplary battery pack with an arc fault detection system coupled between a battery converter and a set of output terminals for detecting an arcing event, according to some end of the present disclosure.

The invention describes a battery pack for an energy generation system includes a cell array of conductively interconnected power cells configured to store and discharge energy, a direct current (DC) -to-DC converter coupled to the cell array and configured to receive power from the cell array during discharging of the cell array or to output power to the cell array during charging of the cell array, a pair of output terminals coupled to the DC-to-DC converter for coupling with an external device; and an are fault detection system coupled between the DC-to-DC converter and the pair of output terminals.

They are a fault detection system that includes a first sensor for measuring power transmitted between the DC-to-DC converter and the pair of output terminals and a controller coupled to the first sensor and configured to disable the battery pack based on a measurement of the power transmitted between the DC-to-DC converter and the output terminals.

The invention provides an arc fault detection system that minimizes damage caused by thermal events in battery packs for energy generation systems by shutting off and/or disabling the battery pack in the event of a thermal event.