Patent Description:
Battery packs are commonly used in portable electrical equipment and tools to facilitate their use in environments where no fixed power supply is available. For example, power tools manufacturers often manufacture a universal power pack that is compatible with different types of cordless power tools, such as electric drills, hammers, screwdrivers, impact wrenches, angle grinders, etc. Power requirements can differ from one power tool to the next. For instance, a power requirement associated with a cordless drill can differ compared to a power requirement associated with a work light. Battery packs range in terms of capacity and quality. Some battery packs have different output capacity, depending on the type of tool to which it is connected. <CIT>; <CIT>; <CIT> and <CIT> each represent prior art according to the preamble of claims <NUM> and <NUM>.

Aspects and advantages of embodiments of the present disclosure will be set forth in part in the following description, or may be learned from the description, or may be learned through practice of the embodiments.

The invention is defined in claims <NUM> and <NUM>; preferred embodiments are discussed in the dependent claims.

These and other features, aspects, and advantages of various embodiments will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the related principles.

Reference now will be made in detail to embodiments, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the embodiments, not limitation of the present disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments without departing from the scope of the present disclosure. Thus, it is intended that aspects of the present disclosure cover such modifications and variations.

Example aspects of the present disclosure are directed to battery packs and battery powered systems. A battery pack can include one or more cells. The one or more cells can store and/or transfer charge (e.g., as power) to power a device (e.g., power tool, electric vehicle, etc.) that is electrically coupled to the battery pack. In some implementations, the one or more cells can include one or more lithium-ion (Li-ion) cells arranged to output direct current at a voltage rating of the battery pack. The battery pack can further include a battery controller. The battery controller can be configured to estimate a state-of-charge of the one or more battery cells. For instance, the battery controller can include one or more memory devices configured to store a state-of-charge algorithm that can be executed by a processing circuit (e.g., application specific integrated circuit (ASIC), processor, field programmable gate array (FPGA), discrete logic, etc.) of the battery controller to cause the battery controller to estimate a state-of-charge of the one or more battery cells.

Power requirements can differ from one device to the next. For instance, a power requirement for a cordless drill can be greater than a power requirement for a work light (e.g., LED spotlight). As such, a usable capacity of the battery pack when transferring charge to the cordless drill can be different (e.g., less) than a usable capacity of the battery pack when transferring charge to the work light. Furthermore, since a state-of-charge of the battery pack is determined based, at least in part, on the usable capacity of the battery pack, it follows that the state-of-charge estimation of the battery pack when transferring charge to the cordless drill will be different (e.g., less) than the state-of-charge estimation of the battery pack when transferring charge to the work light.

Conventional battery controllers can attempt to estimate state-of-charge of the battery pack by using foreknowledge or measurement of the device electrically coupled to the battery pack. However, these methods are inaccurate due to variations in the power requirement of the devices with which the battery pack is compatible. As such, state-of-charge estimations performed by conventional battery controllers do not account for variations in the power requirement of different devices (e.g., cordless power drill, LED spotlight) that can be electrically coupled to the battery pack.

Example aspects of the present disclosure are directed to a method of determining a state-of-charge of a battery pack. When the battery pack is electrically coupled to a device, the device can provide data to the battery controller. The data can be indicative of a power requirement for the device. For instance, a controller associated with the device can be configured to provide the data (e.g., using one or more data packets) to the battery controller via a communication link. In some implementations, the communication link can include a wired communication link. In alternative implementations, the communication link can include a wireless communication link. It should be understood that the data indicative of the power requirement for the device can be provided as an input to the state-of-charge algorithm executed by the processing circuit of the battery controller.

In some implementations, the data indicative of the power requirement for the device can include data indicative of one or more electrical parameters associated with the device. For instance, the one or more electrical parameters can include a maximum current the device must draw in order to perform an action. In some implementations, the one or more electrical parameters can include a rated current for the device. In some implementations, the one or more electrical parameters can include a maximum power the device must draw in order to perform an action. In some implementations, the one or more electrical parameters can include an impedance (e.g., normal, minimum) of the device. It should be appreciated, however, that the one or more electrical parameters can include any suitable parameters of the device that can be used to determine a power requirement for the device.

In some implementations, the data indicative of the power requirement for the device can include data indicative of a transient current the device initially draws when performing an action. For example, the device can be a cordless power drill, and the action can include drilling a hole or driving a fastener (e.g., screw). In such implementations, the data can be indicative of the transient current (e.g., about <NUM> Amps) an electric motor of the cordless power drill initially draws such that the cordless power drill can perform the action.

In some implementations, the data indicative of the power requirement for the device can include a current profile for the device. For instance, the current profile can include data indicative of electrical current the device draws with respect to time. In alternative implementations, the data indicative of the power requirement for the device can include a power profile for the device. For instance, the power profile can include data indicative of electrical power the device draws with respect to time.

In the claimed invention, the data indicative of the power requirement for the device includes data indicative of a model number associated with the device. For instance, the device can be a cordless power tool, and the data indicative of the power requirement for the device can include data indicative of a model number associated with the cordless power tool. In such implementations, the battery controller can be configured to store a look-up table or other data structure that includes the model number and power requirement for a plurality of different power tools (e.g., leaf-blower, chainsaw, impact driver, etc.). For instance, the one or more memory devices of the battery controller can be configured to store the look-up table. The battery controller can be configured to match the model number associated with the device electrically coupled to the battery pack to one of the model numbers included in the look-up table. In this manner, the battery controller can determine a power requirement for the device based, at least in part, on the data indicative of the model number associated with the device.

The method according to the present disclosure can include determining a state-of-charge of the one or more battery cells based, at least in part, on the data indicative of the power requirement for the device. For instance, the battery controller of the battery pack can be configured to adjust the state-of-charge of the one or more battery cells from a first state-of-charge to a second state-of-charge based, at least in part, on the data indicative of the power requirement for the device. In this manner, the state-of-charge of the one or more battery cells can be adjusted based, at least in part, on the power requirement for the device electrically coupled to the battery pack.

In some implementations, the method according to the present disclosure can include providing a notification indicative of the determined state-of-charge of the one or more battery cells for display on a display device. For instance, in some implementations, the battery controller can be configured to provide the notification to the device for display on a display device thereof. Alternatively, or additionally, the battery controller can be configured to provide the notification for display on a display device associated with the battery pack. Other methods for providing a notification indicative of the state-of-charge can be used without deviating from the scope of the present disclosure, such as illumination of one or more indicators (e.g., LED indicators) located on the battery pack and/or the device.

Example aspects of the present disclosure can provide for a number of technical effects and benefits. For instance, the battery controller can obtain data indicative the power requirement for the device electrically coupled to the battery controller. Furthermore, the battery controller can determine the state-of-charge of the battery pack based, at least in part, on the power requirement. More specifically, the battery controller can adjust (e.g., increase or decrease) the state-of-charge of the battery pack based, at least in part, on the power requirement. In this manner, information indicative of the state-of-charge of the battery pack can be adjusted as needed based on different power requirements for the various devices (e.g., power tools, LED spotlights, electric vehicles, etc.) that can be electrically coupled to the battery pack.

Referring now to <FIG>, a cordless power tool <NUM> is provided according to example embodiments of the present disclosure. The cordless power tool <NUM> includes a housing <NUM> and an electric motor <NUM> (denoted in dashed lines) disposed within the housing <NUM>. The electric motor <NUM> can be electrically coupled to a battery pack <NUM> that is removably coupled to housing <NUM> of the cordless power tool <NUM>. In this manner, the electric motor <NUM> can receive electrical energy from the battery pack <NUM>. The electric motor <NUM> can be configured to convert the electrical energy into mechanical energy needed to drive rotation of an object (e.g., drill bit, fastener) retained by a chuck <NUM> of the cordless power tool <NUM>. In some implementations, the cordless power tool <NUM> can include a clutch <NUM>. The clutch <NUM> can be configured to adjust an amount of torque that is delivered to the object. As shown, the cordless power tool <NUM> can include an input device <NUM> configured to receive a user-input associated with controlling operation of the electric motor <NUM>. For instance, the input device <NUM> can include a trigger that a user can pull to provide user-input associated with actuating the electric motor <NUM> to perform an action (e.g., drill a hole, drive a fastener, etc.).

In some implementations, the cordless power tool <NUM> can include a display device <NUM>. The display device <NUM> can be configured to display information associated with operation of the battery pack <NUM>. For instance, in some implementations, the display device <NUM> can display information indicative of a state-of-charge of the battery pack <NUM>. In this manner, a user can determine the state-of-charge of the battery pack by viewing the information displayed on the display device <NUM> of the cordless power tool <NUM>.

Referring now to <FIG>, the battery pack <NUM> is provided according to example embodiments of the present disclosure. As shown, the battery pack <NUM> can include a battery housing <NUM>. The battery housing <NUM> can be configured to accommodate one or more battery cells (not shown). The one or more cells can be configured to store and/or transfer charge (e.g., as power) to power the cordless power tool <NUM> (<FIG>). For instance, the battery housing <NUM> can include a terminal post <NUM> having terminals <NUM>, <NUM>. It should be understood that the one or more battery cells can be electrically coupled to the electric motor <NUM> when the battery housing <NUM> is removably coupled to the cordless power tool <NUM>.

<FIG> depict one example of a power tool and battery pack for purposes of illustration and discussion. Those of ordinary skill in the art, using the disclosures provided herein, will understand that a battery pack can be used to deliver power to devices other than cordless power tools (e.g., drills, leaf blowers, etc.). For instance, in some implementations, the battery pack <NUM> can be used to deliver power to a light emitting diode (LED) spotlight.

Referring now to <FIG>, a battery pack <NUM> electrically coupled to a device <NUM> is provided according to example embodiments. In this manner, the battery pack <NUM> can deliver electrical power to the device <NUM>, specifically a load <NUM> thereof. In some implementations, the device <NUM> can be a cordless power tool, such as the cordless power tool <NUM> discussed above with reference to <FIG>. However, it should be understood that the device <NUM> can include any device having one or more loads configured to receive electrical power from the battery pack <NUM>. For instance, in some implementations, the device <NUM> can be an electric vehicle. In alternative implementations, the device <NUM> can include a light emitting diode (LED) spotlight.

As shown, the battery pack <NUM> can include one or more battery cells <NUM>. The one or more battery cells <NUM> can be configured to store and/or transfer charge (e.g., as power) to the device <NUM> via one or more conductors <NUM>. In some implementations, the load <NUM> of the device <NUM> can be an electric motor. In alternative implementations, the load <NUM> can be a power supply. For instance, the power supply can be a DC/DC power supply for one or more light sources (e.g., LEDs). Alternatively, the power supply can be a DC/DC power supply for a USB output associated with the device <NUM>. In some implementations, the load <NUM> can be a passive electrical component (e.g., resistor).

The battery pack <NUM> can include a battery controller <NUM>. The battery controller <NUM> can be configured to estimate a state-of-charge of the one or more battery cells <NUM>. For instance, the battery controller <NUM> can include one or more memory devices <NUM> configured to store a state-of-charge algorithm that can be executed by a processing circuit <NUM> of the battery controller <NUM> to cause the battery controller <NUM> to estimate a state-of-charge of the one or more battery cells <NUM>. In some implementations, the processing circuit <NUM> can include one or more processors. In alternative implementations, the processing circuit <NUM> can include a field programmable gate array (FPGA) or other discrete logic circuit. As will be discussed below in more detail, the battery controller <NUM> can be configured to obtain information from the device <NUM> that allows the battery controller <NUM> to estimate the state-of-charge of the one or more battery cells <NUM>.

When the battery pack <NUM> is electrically coupled to the device <NUM>, the device <NUM> can provide data to the battery controller <NUM>. The data can be indicative of a power requirement for the device <NUM>. For instance, a controller <NUM> associated with the device <NUM> can be configured to provide the data to the battery controller <NUM> via a communication link <NUM>. In some implementations, the communication link <NUM> can include a wired communication link (e.g., one or more pins or terminals). In alternative implementations, the communication link <NUM> can include a wireless communication link. It should be understood that the data indicative of the power requirement associated with the device <NUM> can be provided as an input to the state-of-charge algorithm executed by the processing circuit <NUM> of the battery controller <NUM>.

In some implementations, the data indicative of the power requirement for the device <NUM> can include data indicative of one or more electrical parameters associated with the device <NUM>. For instance, the one or more electrical parameters can include a maximum current the device <NUM> must draw in order to perform an action. In some implementations, the one or more electrical parameters can include a rated current for the device <NUM>. In some implementations, the one or more electrical parameters can include a maximum power the device <NUM> must draw in order to perform an action. In some implementations, the one or more electrical parameters can include an impedance (e.g., normal, minimum) of the device <NUM>. It should be appreciated, however, that the one or more electrical parameters can include any suitable parameters of the device that can be used to determine a power requirement for the device <NUM>.

In some implementations, the data indicative of the power requirement associated with the device <NUM> can include data indicative of a transient current the device <NUM> initially draws when performing an action. For example, the device <NUM> can be the cordless power tool <NUM> discussed above with reference to <FIG>, and the action can include drilling a hole or driving a fastener (e.g., screw). In such implementations, the data can be indicative of the transient current (e.g., about <NUM> Amps) the cordless power tool <NUM> initially draws when performing the action.

In some implementations, the data indicative of the power requirement for the device <NUM> can include a current profile for the device <NUM>. For instance, the current profile can include data indicative of electrical current the device <NUM> draws with respect to time. In alternative implementations, the data indicative of the power requirement for the device <NUM> can include a power profile for the device <NUM>. For instance, the power profile can include data indicative of electrical power the device <NUM> draws with respect to time.

In the invention, the data indicative of the power requirement includes data indicative of a model number associated with the device <NUM>. For instance, the device <NUM> can be the cordless power tool <NUM> discussed above with reference to <FIG>, and the data indicative of the power requirement can include data indicative of a model number associated with the cordless power tool <NUM>. In such implementations, the battery controller <NUM> can be configured to store a look-up table that includes the model number and power requirement for a plurality of different power tools (e.g., leaf-blower, chainsaw, impact driver, etc.). For instance, the one or more memory devices of the battery controller <NUM> can be configured to store the look-up table. The battery controller <NUM> can be configured to match the model number associated with the device <NUM> to one of the model numbers included in the look-up table. In this manner, the battery controller <NUM> can determine a power requirement for the cordless power tool <NUM> based, at least in part, on the data indicative of the model number associated with the cordless power tool <NUM>.

The battery controller <NUM> can be configured to determine a state-of-charge of the one or more battery cells <NUM> based, at least in part, on the data indicative of the power requirement for the device <NUM>. For instance, the battery controller <NUM> can be configured to adjust the state-of-charge of the one or more battery cells <NUM> from a first state-of-charge to a second state-of-charge based, at least in part, on the data indicative of the power requirement for the device <NUM>. In this manner, the state-of-charge of the one or more battery cells <NUM> can be adjusted based, at least in part, on the power requirement of the device <NUM> electrically coupled to the battery pack <NUM>.

The battery controller <NUM> can be configured to provide a notification indicative of the determined state-of-charge of the one or more battery cells <NUM> for display on a display device. For instance, in some implementations, the battery controller <NUM> can be configured to provide the notification to the device <NUM> via the communication link <NUM> for display on a display device <NUM> associated with the device <NUM>. Alternatively, or additionally, the battery controller <NUM> can be configured to provide the notification for display on a display device <NUM> associated with the battery pack <NUM>.

Referring now to <FIG>, a flow chart of an example method <NUM> of estimating a state-of-charge of a battery pack is provided according to example embodiments of the present disclosure. It should be appreciated that the method <NUM> can be implemented by the battery controller <NUM> discussed above with reference to <FIG>. Furthermore, although <FIG> depicts steps performed in a particular order for purposes of illustration and discussion, the methods of the present disclosure are not limited to the particularly illustrated order or arrangement. It should be understood that the various steps of the method <NUM> can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

At (<NUM>), the method <NUM> includes obtaining, by a battery controller of a battery pack, data from a device electrically coupled to the battery pack. The data can be indicative of a power requirement for the device. Furthermore, the device can be configured to provide the data indicative of the power requirement to the battery controller via a wired or wireless communication link.

In some implementations, the data indicative of the power requirement for the device can include data indicative of one or more electrical parameters associated with the device. For instance, the one or more electrical parameters can include a maximum current the device must draw in order to perform an action. In some implementations, the one or more electrical parameters can include a rated current for the device. In some implementations, the one or more electrical parameters can include a maximum power the device must draw in order to perform an action. In some implementations, the one or more electrical parameters can include an impedance (e.g., normal, minimum) of the device. It should be appreciated, however, that the one or more electrical parameters can include any suitable parameters that can be used to determine a power requirement for the device.

In some implementations, the data indicative of the power requirement for the device can include data indicative of a transient current the device initially draws when performing an action. For example, the device can be a cordless power drill, and the action can include drilling a hole or driving a fastener (e.g., screw). In such implementations, the data can be indicative of the transient current (e.g., about <NUM> Amps) the cordless power drill initially draws when performing the action.

In the invention, the data indicative of the power requirement includes data indicative of a model number associated with the device. For instance, the device can be a cordless power tool, and the data indicative of the power requirement can include data indicative of a model number associated with the cordless power tool. In such implementations, the battery controller can be configured to store a look-up table that includes the model number and power requirement for a plurality of different power tools (e.g., leaf-blower, chainsaw, impact driver, etc.). For instance, the one or more memory devices of the battery controller can be configured to store the look-up table. The battery controller can be configured to match the model number associated with the device to one of the model numbers included in the look-up table. In this manner, the battery controller can determine a power requirement for the device based, at least in part, on the data indicative of the model number associated with the device.

At (<NUM>), the method <NUM> includes determining, by the battery controller, a state-of-charge of the battery pack based, at least in part, on the data indicative of the power requirement. For instance, in some implementations, determining the state-of-charge of the battery pack can include adjusting the state-of-charge of the battery pack from a first state-of-charge to a second state-of-charge. The second state-of-charge can be lower than the first state-of-charge when a second device electrically coupled to the battery pack has a higher power requirement compared to a first device that was electrically coupled to the battery pack immediately before the second device.

At (<NUM>), the method <NUM> includes providing, by the battery controller, a notification indicative of the state-of-charge determined at (<NUM>) for display on a display device. For instance, in some implementations, the display device can be associated with the device. Alternatively, or additionally, the display device can be associated with the battery pack. In this manner, a user associated with the device and/or the battery pack can view the notification indicative of the state-of-charge.

Referring now to <FIG>, a graphical illustrations of how usable capacity of a battery pack or battery-powered system differs for devices with different power requirements is provided according to example embodiments of the present disclosure. As shown, graph <NUM> depicts curves <NUM>, <NUM>, and <NUM>, which each correspond to voltage (denoted along the vertical axis in volts) as a function of capacity (denoted along horizontal axis in amp-hours) of the battery pack. Curve <NUM> corresponds to the open circuit voltage of the battery pack - that is the voltage of the pack or cells at any SOC if no device or a device having a low power requirement is applied to the cell(s). Curve <NUM> corresponds to the external battery voltage of the battery pack when the battery pack is electrically coupled to a first device having a first power requirement. Curve <NUM> corresponds to the external battery voltage of the battery pack when the battery pack is electrically coupled to a second device having a second power requirement that is different than the first power requirement. For instance, the second power requirement associated with the second device can be different (e.g., greater) than the first power requirement associated with the first device. More particularly, an initial current drawn by the second device can be greater than an initial current drawn by the first device. In this manner, a voltage drop across the battery pack when coupled to the second device is greater than a voltage drop across the battery pack when coupled to the first device.

As shown, curve <NUM> intersects line <NUM>, which corresponds to the shutdown voltage of the battery pack or battery-powered system, before curve <NUM> intersects line <NUM>. It should be appreciated that the point at which curves <NUM>, <NUM>, and <NUM> intersect line <NUM> corresponds to a usable capacity (Quse) of the battery pack when coupled to a device having a low power requirement, a first device having a first power requirement, and a second device having a second power requirement, respectively. For instance, the battery pack has a maximum capacity <NUM> when coupled to a device having a low power requirement. Then it has a lesser usable capacity <NUM> when coupled to the first device, and an even lesser usable capacity <NUM> when coupled to the second device. This is due, in part, to the first power requirement of the first device being greater than the low power power requirement, and the second power requirement (e.g., initial current) of the second device being greater than the first power requirement (e.g., initial current) of the first device.

An amount of charge (e.g., Qpass) that has already been depleted (i.e., transferred from battery pack to device) is indicated by line <NUM> in the graph <NUM>. It should be understood that line <NUM> will move to the right (e.g., closer to usable capacity) as the battery pack or battery powered system continues to transfer charge to the device. It should also be understood that a state-of-charge (SOC) of the battery pack can be determined using the below formula: <MAT>.

In the above formula, Qpass corresponds to the amount of charge that has already been depleted. Additionally, Quse corresponds to the usable capacity of the battery pack. As shown in the graph <NUM>, a difference <NUM> (e.g., delta) between line <NUM> and the usable capacity <NUM> of the first device is greater than a difference <NUM> (e.g., delta) between line <NUM> and the usable capacity <NUM> of the second device. As such, the SOC of the battery pack or battery powered system when coupled to the first device is greater than the SOC of the battery pack or battery powered system when coupled to the second device. This is due, in part, to the first power requirement (e.g., initial current) associated with the first device being lower than the second power requirement (e.g., initial current) associated with the second device.

As discussed above, the battery controller of the battery pack according to the present disclosure can be configured to adjust the state-of-charge of the battery pack to account for variations in the power requirement of the different devices that can be coupled to the battery pack. In this manner, the state-of-charge of the battery pack determined by the battery controller according to the present disclosure can be specific to the device that is currently coupled to the battery pack.

Referring now to <FIG>, a flow chart of a method <NUM> of controlling operation of a device electrically coupled to a battery pack is provided according to example embodiments of the present disclosure. It should be appreciated that the method <NUM> can be implemented by the controller <NUM> of the device <NUM> discussed above with reference to <FIG>. Furthermore, although <FIG> depicts steps performed in a particular order for purposes of illustration and discussion, the methods of the present disclosure are not limited to the particularly illustrated order or arrangement. It should be understood that the various steps of the method <NUM> can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

At (<NUM>), the method <NUM> can include obtaining, by a controller of the device, data from the battery pack electrically coupled to the device. The data can be indicative of an impedance of the battery pack. In some implementations, a battery controller of the battery pack can provide the data (e.g., impedance) to the device via a wired communication link. In alternative implementations, the battery controller can provide the data to the device via a wireless communication link.

At (<NUM>), the method <NUM> can include determining, by the controller of the device, an adjustment to a maximum amount of electrical power the device draws from the battery pack based, at least in part, on the data obtained at (<NUM>). For instance, determining an adjustment to the maximum amount of electrical power an electric motor of the device draws from the battery pack can include adjusting, by the battery controller, an electric current the electric motor draws from the battery pack. More particularly, the electric current the electric motor draws from the battery pack can be reduced when the data obtained at (<NUM>) indicates the impedance of the battery pack is below a threshold value. At (<NUM>), the method <NUM> can include controlling, by the controller of the device, operation of the device such that the device draws the adjusted amount of electrical power.

Claim 1:
A method of estimating a state-of-charge of a battery pack (<NUM>, <NUM>) comprising a plurality of cells (<NUM>), the method comprising:
obtaining, by a battery controller (<NUM>) of the battery pack (<NUM>, <NUM>), data from a power tool (<NUM>) electrically coupled to the battery pack (<NUM>, <NUM>), the data indicative of a power requirement for the power tool (<NUM>); and
determining, by the battery controller (<NUM>), a state-of-charge of the battery pack (<NUM>, <NUM>) based, at least in part, on the data indicative of the power requirement for the power tool (<NUM>) which comprises adjusting, by the battery controller (<NUM>), the state-of-charge of the battery pack (<NUM>, <NUM>) from a first state-of-charge to a second state-of-charge based, at least in part, on the data indicative of the power requirement for the power tool (<NUM>),
characterized in that :
obtaining data indicative of a power requirement for the power tool (<NUM>) comprises obtaining, by the battery controller (<NUM>), data indicative of a model number assigned to the power tool (<NUM>).