Patent Description:
Battery packs are commonly used in portable electrical equipment and tools, so that these equipment and tools can be used in environments where no fixed power supply is available. For example, power tools manufacturers often manufacture a universal power pack which can be compatibly used in different types of cordless power tools, such as electric drills, hammers, screwdrivers, impact wrenches, angle grinders, etc. The battery packs usually include a plurality of battery cells accommodated in an integral housing where the user can easily install the entire battery into the power tool, or remove it therefrom via latching mechanisms configured on the battery pack housing and/or the power tool.

<CIT> shows a charge control device that limits upper limits of a charging current and a charging voltage according to ambient temperature conditions to which battery cells of a battery are exposed, a battery pack provided with the charge control device, and a charger. The battery pack comprises a battery with a plurality of battery cells. The charger comprises a charging circuit that charges the battery by receiving power supply from an external power source, a charge control circuit that controls the charging of the battery by the charging circuit, and an indication unit that indicates an operating state of the charger. The battery is a lithium-ion battery. In the charging process, a relevant charging current characteristic is determined based on the outputtable current of the charger. Based on the temperature of the battery, the relevant temperature range, which sets the constant charging current, is selected.

<CIT> discloses systems and methods for controlling battery cell charge current based on the ambient temperature conditions to which battery cells of a battery system are exposed, for example, to control battery cell charging current for battery systems that may be exposed to environments where ambient temperature conditions are not controllable. The method of controlling charge current provided to one or more battery cells during a charge cycle comprises the steps of sensing a temperature representative of an ambient temperature to which said one or more battery cells are exposed during said charge cycle, determining a value of charge current to be provided to said one or more battery cells during said charge cycle using a temperature-dependent current regulation algorithm and based on said sensed temperature; and providing said determined value of charge current to said one or more battery cells as a constant charge current during said charge cycle, wherein said temperature-dependent current regulation algorithm comprises a plurality of charge current control values, or wherein said temperature-dependent algorithm is implemented by software, or a combination thereof.

<CIT> refers to a battery pack und to a method of charging the battery pack that shorten the charging time while protecting the battery pack from heat generation. The battery pack is charged following a charging profile of the charging current wherein the charging current is set depending on the temperature of the battery pack. The charging current can be <NUM> for a first temperature range, can set to a constant value for a defined temperature range and the charging current can decrease with increasing temperatures.

<CIT> shows a battery pack including a battery with at least one battery cell and with a battery manager for measuring a temperature of the battery cell. The battery manager is configured to set a charging current limit according to the temperature of the battery cell. The charging current limit is set differently for different temperature ranges. Depending on the temperature of the battery/the battery cell, the charging current limit can be set to <NUM>, can have a constant value, can increase with increasing temperature or can decrease with increasing temperature.

<CIT> describes a lithium-ion rechargeable battery with a charging/discharging control circuit. During charging of the battery, the charging/discharging control circuit detects the temperature of the lithium-ion battery, and cutoffs charging of the lithium-ion battery when the temperature of the lithium-ion battery raises to a charging upper threshold temperature TCH. The charging/discharging control circuit restores charging of the lithium-ion battery when the temperature of the lithium-ion battery decreases to be lower than a temperature obtained by subtracting a backlash temperature form the charging upper threshold temperature, i.e., TCH -ΔT1. TCH is a charging upper threshold temperature of the lithium-ion battery set based on the charging technical specifications of the lithium-ion battery for the universal rechargeable battery, and ΔT1 is a backlash temperature corresponding to a backlash voltage of the TCH detection threshold set by a voltage detection circuit of the thermistor Rt.

The invention is claimed in claim <NUM>. Dependent claims <NUM>-<NUM> claim preferred embodiments. One example aspect of the present disclosure is directed to a battery pack. The battery pack can include one or more cells. The battery pack can include at least one temperature sensor configured to obtain a temperature measurement indicative of a temperature of at least cell of the one or more cells. The battery pack can include a controller, the controller configured to be placed in signal communication with a battery charger. The controller can be configured to perform operations. The operations can include obtaining the temperature measurement from the at least one temperature sensor. The operations can include determining, based at least in part on the temperature measurement, that the temperature of the at least one cell is between a lower temperature threshold and an upper temperature threshold. The operations can include, in response to determining that the temperature of the at least one cell is between the lower temperature threshold and the upper temperature threshold, reducing a maximum charging current, wherein reducing the maximum charging current comprises reducing the maximum charging current based at least in part on an inverse functional relationship between the temperature measurement and the maximum charging current wherein the maximum charging current is reduced across at least a temperature-inverse region. The operations can include determining, based at least in part on the temperature measurement, that the temperature of the at least one cell is greater than the upper temperature threshold; in response to determining that the temperature of the at least one cell is greater than the upper temperature threshold, halting charging of the battery pack; determining, subsequent to halting charging of the battery, that the temperature of the at least one cell reaches the lower temperature threshold within the temperature-inverse region; and in response to determining that the temperature of the at least one cell reaches the lower temperature threshold within the temperature-inverse region, resuming charging of the battery pack by reducing the maximum charging current based in part on the inverse functional relationship between temperature measurement and the maximum charging current. The operations can include controlling the battery charger based at least in part on the maximum charging current to charge the one or more cells.

Furthermore, a method for charging a battery pack while avoiding an over-temperature condition is described. The method can include obtaining a temperature measurement indicative of a temperature of at least one cell from the at least one temperature sensor. The method can include determining, based at least in part on the temperature measurement, that the temperature of the at least one cell is between a lower temperature threshold and an upper temperature threshold. The method can include, in response to determining that the temperature of the at least one cell is between the lower temperature threshold and the upper temperature threshold, reducing a maximum charging current, wherein reducing the maximum charging current comprises reducing the maximum charging current based at least in part on an inverse functional relationship between the temperature measurement and the maximum charging current. The method can include controlling a battery charger based at least in part on the maximum charging current to charge the at least one cell.

In the drawings, like numerals indicate like parts throughout the several embodiments described herein.

In the claims which follow and in the preceding description of the example aspects of the present disclosure, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the example aspects of the present disclosure.

As used herein and in the claims, "couple" or "connect" refers to electrical coupling or connection either directly or indirectly via one or more electrical means unless otherwise stated.

Terms such as "horizontal", "vertical", "upwards", "downwards", "above", "below" and similar terms as used herein are for the purpose of illustration of example embodiments in normal in-use orientation and are not intended to limit the disclosure to any particular orientation.

Example aspects of the present disclosure are directed to a battery pack. The 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 electrical devices, such as electric tools, garden tools, etc. Battery packs may be configured to have various DC voltage levels (e.g., <NUM> volts, <NUM> volts, <NUM> volts, <NUM> volts, <NUM> volts, etc.). For example, the battery packs can be <NUM> volt battery packs, <NUM> volt battery packs, <NUM> volt battery packs, or another voltage. In an example, the battery packs can include one or more lithium-ion (Li-ion) cells arranged to output direct current at a voltage rating of the battery pack. In some embodiments, electrodes of the cells can be or can include graphite electrodes. Other suitable materials may be included in the electrodes of the cells.

In some embodiments, the battery cells in the battery packs can be rechargeable lithium-ion cells. In other constructions, the battery cells may have a chemistry other than lithium-ion such as, for example, nickel cadmium (NiCa or NiCad), nickel metal-hydride, and the like. In one embodiment, the batteries are power tool battery packs including a pack housing containing one or more battery cells and latching mechanisms for selectively securing the battery packs to the battery interfaces.

Furthermore, the battery pack including the one or more cells can be charged and/or recharged by a battery charger. For instance, the battery pack can be connected to a battery charger that is configured to receive the battery pack, such as configured to accept the battery pack into a battery receptacle. As one example, the battery pack can include one or more slot mechanical connectors (e.g., rails) configured to engage with one or more slots at the battery charger to couple the battery pack to the battery charger. When the battery pack is connected to the battery charger, the battery charger can supply power (e.g., voltage and/or current) to the battery pack (e.g., to the one or more cells) to charge the battery by increasing charge of the cell(s). In some embodiments, the battery pack and/or battery charger can be configured in a constant voltage mode that supplies a constant voltage to the battery back, such as by decreasing current over time to maintain a constant (e.g., specified) voltage as the battery charges. Additionally and/or alternatively, the battery pack and/or battery charger can be configured in a constant current mode that supplies a constant (e.g., specified) current to the battery pack. This generally causes voltage of the battery pack (e.g., cell voltage) to increase with charge.

The battery pack can include a battery controller. The battery controller can be placed in signal communication with the battery charger, such as with a charger controller of the battery charger. For example, the battery controller can be coupled (e.g., by one or more signal pins and/or other terminals) to the charger controller when the battery pack is received by the battery charger. The battery controller can request an amount of current from the battery charger to charge the battery. For example, the battery controller can communicate data indicative of a requested amount of current to be provided by the battery charger to the charger controller. The charger controller can control the battery charger to provide the requested amount of current to the battery. In some embodiments, the requested amount of current can be an upper current limit. For instance, the charger may deliver an amount of current that is less than or equal to the upper current limit. For example, if a battery pack communicates a request for <NUM> amps to a battery charger that is only capable of providing <NUM> amps, the battery charger may provide only <NUM> amps. However, if the battery pack communicates a request for <NUM> amps to the same <NUM> amp battery charger, the battery charger may provide <NUM> amps. In this way, the battery pack can intelligently limit the amount of current it receives while having compatibility with various chargers.

Generally, battery packs can be subject to temperature constraints. For instance, it can be necessary to maintain a battery pack at or below an upper temperature limit. Temperature of the battery can increase during use and/or charging. Exceeding the upper temperature limit, resulting in an over-temperature condition, can cause complications such as safety risks, reduction of battery life, damage to the battery and/or other systems, and/or other complications. Additionally, in the event of an over-temperature condition, it can be necessary to mitigate the over-temperature condition such as by halting charging until the battery pack has returned to a lower temperature. This can significantly increase an amount of time required to charge the battery pack. As such, it is generally desirable to avoid over-temperature conditions by maintaining a battery pack at or below an upper temperature limit and/or avoiding exceeding an upper temperature limit.

According to example aspects of the present disclosure, the battery controller can monitor a temperature of the battery pack. As one example, the battery controller can monitor temperature of the cell(s) of the battery pack. For instance, in some embodiments, the battery pack can include one or more temperature sensors respective to at least one cell. The temperature sensor(s) can obtain a temperature measurement from the at least one cell. The battery controller can obtain the temperature measurement from the temperature sensor(s).

In some embodiments, the temperature measurement may be made available to the battery charger. For instance, in some embodiments, the temperature measurement may be available at a temperature measurement terminal at the battery pack. For instance, when the battery pack is received at a device (e.g., the battery charger), the temperature measurement terminal may convey a temperature measurement signal (e.g., a digital and/or analog signal) that is descriptive of the temperature measurement to the device to which the battery pack is coupled (e.g., the battery charger).

According to example aspects of the present disclosure, a battery controller can be configured to perform operations. The operations can include, for example, a method for charging a battery pack while avoiding an over-temperature condition. For instance, according to example aspects of the present disclosure, the battery controller can implement the operations to charge the battery while preventing the over-temperature condition. Furthermore, in the event that the over-temperature condition occurs regardless, the operations can, in some embodiments, contribute to mitigating the over-temperature condition.

The method can include obtaining a temperature measurement indicative of a temperature of at least one cell from a temperature sensor. The temperature measurement can be indicative of a temperature of the battery pack (e.g., a temperature of the at least one cell). The temperature measurement can be communicated to the battery controller. In one example embodiment, a single temperature sensor is configured to obtain a temperature measurement of one cell to determine the temperature of the battery pack. For example, the temperature measurement of a single cell can be extrapolated to represent the temperature of the battery pack. Other suitable temperature measurement configurations may be employed in accordance with example embodiments of the present disclosure.

The method can include determining, based at least in part on the temperature measurement, that the temperature of the at least one cell is between a lower temperature threshold and an upper temperature threshold. For instance, the lower temperature threshold can be at a temperature at which it becomes desirable to begin reducing current to the battery pack to avoid the over-temperature condition. Generally, the lower temperature threshold can be any suitable temperature and may be a temperature that is less than (e.g., about <NUM> degrees Celsius less than) the upper temperature threshold. Furthermore, in some embodiments, the upper temperature threshold can be at an upper temperature limit, such as a temperature at which an over-temperature condition occurs. The battery controller can determine that the temperature of the at least one cell is between a lower temperature threshold and an upper temperature threshold in any suitable manner, such as, for example, by a threshold comparison. Additionally and/or alternatively, the determination may be performed as a result of inputting the temperature into a mathematical model.

Additionally and/or alternatively, the method can include, in response to determining that the temperature of the at least one cell is between the lower temperature threshold and the upper temperature threshold, reducing a maximum charging current. For instance, reducing the maximum charging current can include reducing a maximum charging current that is requested from a battery charger (e.g., by a charging current request). According to example aspects of the present disclosure, reducing the maximum charging current can include reducing the maximum charging current based at least in part on an inverse functional relationship between the temperature measurement and the maximum charging current. For instance, the inverse functional relationship can provide that a maximum charging current will decrease as temperature of the at least one cell increases over at least a portion of the region from the lower temperature threshold to the upper temperature threshold. For instance, the inverse functional relationship can provide that a maximum charging current at the upper temperature threshold is less than at least a maximum charging current at the lower temperature threshold. Additionally and/or alternatively, the maximum charging current can be allowed to recover (e.g., increase) as the temperature decreases (e.g., after reducing the current). In some embodiments, the inverse functional relationship can be a monotonically decreasing relationship. For example, in some embodiments, the inverse functional relationship can be a linearly decreasing relationship. For example, the maximum charging current can decrease linearly with respect to increasing temperature. Other suitable functional relationships can be employed in accordance with example aspects of the present disclosure, such as an exponentially decreasing function, step function, etc..

In some embodiments, the inverse functional relationship can be or can include a mathematical model or function. For example, a computing system can compute the maximum charging current based on a formula or mathematical model. As another example, the inverse functional relationship can be or can include a lookup table. For example, the maximum charging current can be retrieved from a lookup table where temperature is provided to the lookup table as input. Other suitable systems for utilizing an inverse function relationship (e.g., thresholding) can be employed in accordance with example aspects of the present disclosure. As one example, the maximum charging current can be determined with respect to a temperature-based current limit from a temperature current-curve. The temperature-current curve can be stored in non-transitory computer-readable media, such as, for example, flash memory, RAM, ROM, EEPROM, hard disk memory, solid state memory, and/or any other suitable memory. For instance, in some embodiments, the curve can be stored as a lookup table, mathematical relationship or model, or other suitable representation.

In some embodiments, the maximum charging current can be based on various other current limits established with respect to other factors of the battery pack. For example, the current limit(s) can be established by various criteria of the battery, such as, but not limited to, state of charge, battery voltage, cell voltage, charging type (e.g., constant current vs. constant voltage), charging status, charging progression, etc. One of these current limits can be established with respect to temperature of the battery pack, such as based on the inverse functional relationship between temperature and charging current. For example, the lowest current limit may be used as the maximum charging current.

Additionally and/or alternatively, the method can include requesting, from the battery charger, the maximum charging current for charging the one or more cells. For instance, in some embodiments, the battery controller can determine a charging current request. The charging current request can specify a requested amount of current to be provided to the battery for charging the battery, such as the maximum charging current. The charging current request can be communicated to the battery charger, such as a charger controller. In some embodiments, the maximum charging current can be periodically requested from the battery charger. For example, the maximum charging current can be requested in periodic intervals, such as at set time intervals, including regular intervals and/or irregular intervals, in response to stimuli, etc. For instance, the maximum charging current may be determined and requested at regular intervals to ensure that the current is updated as necessary.

After receiving the charging current request, the charger controller can configure a battery charger (e.g., a supply) to deliver the amount of current that is specified by the charging current request to the battery pack (e.g., cells). As one example, a battery pack and/or a battery charger can include one or more charging terminals configured to provide electrical connection between the one or more cells and the battery charger, such as between the one or more cells and the supply. In some embodiments, the charging current request is periodically communicated to the battery charger. For example, the charging current request can be communicated at set time intervals, in response to stimuli, etc..

In some embodiments, the battery controller can further be configured to mitigate an over-temperature condition at a battery pack. For instance, example aspects of the present disclosure can generally reduce likelihood of an over-temperature condition, such as by decreasing temperature of the battery pack as a result of reduced current to the battery pack. Despite this, in some example cases, it can still be desirable to entirely halt charging of the battery pack if the over-temperature condition is nonetheless reached.

For instance, the method can further include determining, based at least in part on the temperature measurement, that the temperature of the at least one cell is greater than the upper temperature threshold. For example, the battery controller can compare the temperature of the cell(s) to the upper temperature threshold. If the temperature meets or exceeds the upper temperature threshold, it can be desirable to halt charging the battery pack. For instance, in response to determining that the temperature of the one or more cells is greater than the upper temperature threshold, the method can include halting charging of the battery pack. For instance, halting charging of the battery pack can include requesting a minimus current from the battery charger while charging is halted. The minimus current can be a current that is at or near zero amps, such as less than about <NUM> amps, such as <NUM> amps. For example, halting charging of the battery pack can include communicating a halt current request to the battery charger, where the halt current request includes a request for about zero amps.

The battery controller can further be configured to determine, subsequent to halting charging of the battery, that the temperature of the at least one cell is less than the lower temperature threshold. For instance, the temperature of the at least one cell being less than the lower temperature threshold can generally be indicative that charging can safely be resumed. In response to determining that the temperature of the one or more cells is less than the lower temperature threshold, the method can include resuming charging of the battery pack. For instance, once the battery pack reaches the lower temperature threshold, the battery controller can resume determining a maximum charging temperature based on a temperature measurement, as described herein.

Some example aspects of the present disclosure may be discussed herein with reference to the battery controller performing operations such as, for example, obtaining a temperature measurement from at least one temperature sensor, determining, based at least in part on the temperature measurement, that the temperature of at least one cell is between a lower temperature threshold and an upper temperature threshold, in response to determining that the temperature of the at least one cell is between the lower temperature threshold and the upper temperature threshold, reducing a maximum charging current, wherein reducing the maximum charging current comprises reducing the maximum charging current based at least in part on an inverse functional relationship between the temperature measurement and the maximum charging current, and requesting, from the battery charger, the maximum charging current for charging the one or more cells for the purposes of illustration. It should be understood that some or all of these steps may be performed at a computing device other than the battery controller, such as, for example, the charger controller. For instance, in some embodiments, the battery pack may communicate the temperature measurement to the battery charger, such as by a communication terminal or communication pin on the battery pack and/or the battery charger. The charger controller may obtain the temperature measurement from the battery pack (e.g., via the terminal) and perform the operations for limiting the maximum charging current at the controller. This can be beneficial in cases where the battery pack is incapable of performing the methods described herein, such as in cases where the battery pack lacks a battery controller, cases providing legacy support for batteries with firmware that cannot be updated, etc..

Example aspects of the present disclosure can provide for a number of technical effects and benefits. As one example, example aspects of the present disclosure can provide for reduced charge time of a battery pack. For instance, it can be necessary to halt charging in the case of a battery pack exceeding an upper temperature limit. Systems and methods according to example aspects of the present disclosure can provide for proactively reducing current from a charger in advance of a battery pack reaching an upper temperature limit, such as the upper temperature limit. In this way, the battery pack can avoid reaching the upper temperature limit, which can in turn prevent time-costly interruptions in charging due to reaching the upper temperature limit. As another example, example aspects of the present disclosure can increase battery life. For instance, example aspects of the present disclosure can maintain a battery at or below an upper temperature limit which can prevent reduction in battery life associated with exceeding the upper temperature limit.

Referring now to the FIGS. , example embodiments of the present disclosure will be discussed with reference to the FIGS. for the purposes of illustration. <FIG> illustrate a typical tool battery <NUM> and a cordless (battery power) tool <NUM>. The illustrated tool <NUM> is a drill or driver having a tool housing <NUM> and a pistol type handle <NUM>. A motor <NUM> (indicated by broken lines) is located within the housing for driving a tool output <NUM>. A battery <NUM> is connectable to a supported by the tool handle <NUM>. A tool controller such as a trigger <NUM> is located adjacent the junction between the housing <NUM> and handle <NUM> for coupling energy from the battery <NUM> to the motor <NUM>. This is, however, not intended to limit the scope of use of a battery according to example aspects of the present disclosure. Such a battery could be used in other types of cordless tools and, in particular, in handheld cordless tools or in cordless lawn and garden equipment such as lawn mowers, hedge trimmers and the like. Such a battery could also be used in floor care products such as vacuum cleaners, hand-vacs and cordless sweepers.

One embodiment of a battery for such types of cordless tools has a battery pack housing <NUM> having a mating face <NUM> for connecting to the tool. The battery housing <NUM> is selectively receivable with and supportable by the tool housing via battery connection features, and may be selectively separated from the tool for charging in a separate charger (not shown). For instance, one example embodiment of battery mating features is illustrated in <FIG>. In the illustrated embodiment the battery connection features are a terminal post <NUM> and battery terminals <NUM>, <NUM> on the post <NUM> for connecting the battery energy sources with the tool controller or trigger <NUM>. In alternative embodiments the battery connection features may be slide-type or rail-type connection features or any other type of battery connection features known in the art. For example, instead of being included at terminal post <NUM>, the battery terminals <NUM> and <NUM> may be disposed on the mating face <NUM> and configured to be mated as the battery <NUM> is received at tool handle <NUM> by sliding the battery <NUM> along one or more rails. Any other suitable battery connection features can be employed according to example embodiments of the present disclosure.

<FIG> illustrates a schematic diagram of an example battery pack charging system <NUM> according to example embodiments of the present disclosure. The battery pack charging system <NUM> can include a battery charger <NUM>. The battery charger <NUM> can be removably coupled to a battery pack <NUM>. For instance, the battery charger <NUM> can be configured to receive battery pack <NUM>. As one example, battery charger <NUM> can receive battery pack <NUM> at a cavity, slot, and/or other attachment mechanism configured to couple to and/or establish electrical communication (e.g., signal communication) between the battery charger <NUM> and battery pack <NUM>. As one example, battery pack <NUM> can include one or more slot mechanical connectors configured to engage with one or more slots at the battery charger <NUM> to couple the battery pack <NUM> to the battery charger <NUM>.

The battery pack <NUM> can include one or more cells <NUM>. The one or more cells <NUM> can store and/or transfer charge (e.g., as power) to power electrical devices, such as electric tools, garden tools, etc. Furthermore, the one or more cells <NUM> can be charged and/or recharged by a battery charger <NUM>. For instance, the battery pack <NUM> can be connected to a battery charger <NUM> that is configured to receive the battery pack <NUM>, such as configured to accept the battery pack <NUM> into a battery receptacle. When the battery pack <NUM> is connected to the battery charger <NUM>, the battery charger <NUM> can supply power (e.g., voltage and/or current) by a power signal, such as a voltage signal and/or a current signal, to the battery pack <NUM> (e.g., to the one or more cells <NUM>) to charge the battery by increasing charge of the cell(s). In some embodiments, the battery pack <NUM> and/or battery charger <NUM> can be configured in a constant voltage mode that supplies a constant voltage signal to the battery back, such as by decreasing current over time to maintain a constant voltage at the battery charger <NUM>. Additionally and/or alternatively, the battery pack <NUM> and/or battery charger <NUM> can be configured in a constant current mode that supplies a constant current signal to the battery pack <NUM>. This generally causes voltage of the battery pack <NUM> (e.g., cell voltage) to increase with a state of charge.

The battery charger <NUM> can be configured to charge battery pack <NUM>. For instance, the battery charger <NUM> can include supply <NUM>. Supply <NUM> can be configured to supply power by providing a power signal, such as a voltage signal and/or a current signal, to cell(s) <NUM> of battery pack <NUM> to charge battery pack <NUM>. For instance, the supply <NUM> can supply power that is stored in cells <NUM>. The supply <NUM> can be a DC supply configured to provide a DC power signal, such as a DC supply including an AC/DC converter. For example, supply <NUM> can receive a first power signal, such as an AC signal, such as an AC signal from a power outlet, etc., and convert the first power signal to a second power signal, such as a DC signal, such as a DC current signal rated for charging battery pack <NUM>.

The battery pack <NUM> can include a battery controller <NUM>. The battery controller <NUM> can be placed in signal communication with the battery charger <NUM>, such as with a charger controller <NUM> of the battery charger <NUM>. For example, the battery controller <NUM> can be coupled (e.g., by one or more signal pins and/or other terminals) to the charger controller <NUM> when the battery pack <NUM> is received by the battery charger <NUM>. The battery controller <NUM> can request an amount of current from the battery charger <NUM> to charge the battery. For example, the battery controller <NUM> can communicate a request for a requested amount of current to be provided by the battery charger <NUM> to the charger controller <NUM>. The charger controller <NUM> can control the battery charger <NUM> to provide the requested amount of current to the battery. For instance, the battery charger <NUM> and/or battery back <NUM> can include one or more charging terminals configured to provide electrical connection and/or electrical communication between the one or more cells <NUM> and the battery charger <NUM> (e.g., supply <NUM>). The charging terminals can be connectable and/or disconnectable such that the battery pack <NUM> can be removed from battery charger <NUM> and/or connected to a device utilizing battery pack <NUM>, such as an electrical tool.

In some embodiments, the requested amount of current can be an upper current limit. For instance, the charger may deliver an amount of current that is less than or equal to the upper current limit. For example, if a battery pack <NUM> communicates a request for <NUM> amps to a battery charger <NUM> that is only capable of providing <NUM> amps, the battery charger <NUM> may provide only <NUM> amps. However, if the battery pack <NUM> communicates a request for <NUM> amps to the same <NUM> amp battery charger <NUM>, the battery charger <NUM> may provide <NUM> amps.

Supply <NUM> can be controlled by charger controller <NUM>. For instance, charger controller <NUM> can obtain (e.g., from the battery controller <NUM>) and/or otherwise determine an amount of voltage and/or current to be provided to battery pack <NUM>. Charger controller <NUM> can configure supply <NUM> to provide the determined amount of voltage and/or current to battery pack <NUM>. For instance, in some embodiments, the charger controller can adjust characteristics of one or more digital signals, such as pulse width modulated (PWM) signals, to configure an amount of current and/or voltage and/or power supplied by the supply <NUM>. For instance, the controller can adjust the voltage and/or current at battery pack <NUM> by adjusting duty cycle, frequency/period, etc. of one or more pulse width modulation circuits at supply <NUM>. As another example, in some embodiments, charger controller <NUM> can adjust other components of supply <NUM>, such as variable components, such as variable resistors, varactors, switches, etc., to configure an amount of current and/or voltage and/or power supplied by the supply <NUM>. For example, charger controller <NUM> can be configured to adjust the power signal from supply <NUM> (e.g., for charging the cell(s) <NUM>) based at least in part on the maximum charging current (e.g., from battery controller <NUM>) as described herein.

In some embodiments, control of the battery charger <NUM> may be performed at least partially by another controller than battery controller <NUM>, such as, for example, the charger controller <NUM>. For instance, in some embodiments, the battery pack <NUM> may communicate the temperature measurement from the temperature sensor <NUM> directly to the charger controller <NUM>, such as by a temperature measurement terminal on the battery pack <NUM> and/or the battery charger <NUM>. The charger controller <NUM> may obtain the temperature measurement (e.g., indirectly) from the temperature sensor <NUM> (e.g., via the temperature measurement terminal) and control supply <NUM> based on the temperature measurement, as described herein. This can be beneficial in cases where the battery pack <NUM> is incapable of performing the methods described herein, such as in cases where the battery pack <NUM> lacks a battery controller <NUM>, cases providing legacy support for battery packs <NUM> with firmware (e.g., at battery controller <NUM>) that cannot be updated, etc..

Referring now to <FIG>, one example temperature-current curve <NUM> that may be employed in accordance with example aspects of the present disclosure is illustrated. <FIG> illustrates an example temperature-current curve <NUM> according to example embodiments of the present disclosure. Curve <NUM> can generally describe behavior of some embodiments according to example embodiments of the present disclosure. For instance, accessing the temperature-current curve <NUM> can be one example of implementing the systems and methods described herein. As other examples, the systems and methods described herein can be implemented by threshold checks, look up tables, mathematical functions and/or models, approximations of curve <NUM> (e.g., discretized curves), and/or other suitable representations.

The temperature-current curve <NUM> can include a temperature-invariant region <NUM>, a temperature-inverse region <NUM>, and an over-temperature region <NUM>. For instance, temperature-inverse region <NUM> can span from lower temperature threshold <NUM> to upper temperature threshold <NUM>. For instance, the temperature-inverse region <NUM> can span from a lower temperature threshold at lower temperature threshold <NUM> to an upper temperature threshold at upper temperature threshold <NUM>. For instance, the temperature-inverse region can span over a portion of the temperature-current curve that is limited by the lower temperature threshold <NUM> and the upper temperature threshold <NUM>. The temperature-inverse region <NUM> can define an inverse relationship between temperature and current over the temperature-inverse region <NUM>. For instance, the current can be reduced across the temperature-inverse region <NUM>.

The temperature-invariant region <NUM> can include some or all temperatures below the lower temperature threshold <NUM>. As illustrated, the current can be constant and/or temperature-invariant within temperature-invariant region <NUM>. For instance, the current limit may be unaffected by temperature in the temperature-invariant region <NUM>. For example, the temperature-invariant region <NUM> may define a constant value, such as an overall upper current limit on the battery pack <NUM>.

Furthermore, the over-temperature region <NUM> can include some or all temperatures above the upper temperature threshold (e.g., upper temperature limit) <NUM>. For instance, it can be desirable to maintain the temperature of a battery pack (e.g., battery pack <NUM>) at and/or below upper temperature threshold <NUM>. As such, the current can be reduced to zero at temperatures at and/or above upper temperature threshold <NUM>.

In some embodiments, if a temperature of a battery pack enters over-temperature region <NUM> (e.g., exceeds upper temperature threshold <NUM>), the battery pack can halt current charging until the battery pack reaches a lower temperature threshold, such as lower temperature threshold <NUM>. For instance, in the event that a temperature enters over-temperature region <NUM>, the temperature-current curve can shift to cooldown region <NUM> (e.g., in place of temperature-inverse region <NUM>) to allow a temperature of the battery pack to cool to reach lower temperature threshold <NUM>. For instance, the battery pack may request a minimus current until a temperature of the battery pack reaches lower temperature threshold <NUM>, at which point the battery pack may resume following temperature-inverse region <NUM>.

<FIG> illustrates a plot <NUM> of battery parameters during a charging process according to example embodiments of the present disclosure. For instance, plot <NUM> includes current curve <NUM>. Current curve <NUM> illustrates an amount of current (e.g., in amperes) that is provided to one or more cells (e.g., from a battery charger) over time. Additionally, plot <NUM> includes temperature curve <NUM>. Temperature curve <NUM> illustrates temperature (e.g., in degrees Celsius) of a battery pack (e.g., of at least one cell) that is being charged over time. Additionally, plot <NUM> includes voltage curve <NUM>. Voltage curve <NUM> illustrates a voltage (e.g., in volts) of the battery pack (e.g., from one or more cells in the battery pack) over time. Additionally, plot <NUM> includes state of charge curve <NUM>. State of charge curve <NUM> illustrates a state of charge (e.g., in percentage) of the battery pack over time. For instance, a state of charge of <NUM>% indicates that the battery is completely charged, while a state of charge of <NUM>% indicates that the battery is depleted.

Plot <NUM> depicts a charging process for a battery over various stages in time. For instance, at time <NUM>, the battery pack can begin charging. For instance, as illustrated by current curve <NUM>, a nonzero amount of current can be provided to the battery pack at time <NUM> to begin charging the battery. Prior to time <NUM>, the battery pack may have been previously depleted or otherwise used such that the battery pack is at an incomplete charge. For instance, as illustrated by state of charge curve <NUM>, the battery pack can initially have a state of charge that is near <NUM>%. Furthermore, use of the battery pack may have heated the battery pack (e.g., the one or more cells) above room temperature or other ambient temperature of the battery pack.

At time <NUM>, the battery pack can begin reducing the current based on the increasing temperature of the battery pack. For instance, as illustrated, the "full" amount of current provided by the charger from time <NUM> to time <NUM> may cause the temperature of the battery pack to increase as a result of the current. At time <NUM>, the temperature of the battery pack may first exceed a lower temperature threshold such that the maximum charging current now is related to the temperature of the battery pack by an inverse functional relationship. Additionally and/or alternatively, the temperature may have exceeded the lower temperature threshold before time <NUM>, but the reduced maximum current from the temperature may have been higher than a current limit from another factor and/or a maximum current that the battery charger is capable of providing. As illustrated between time <NUM> and time <NUM> by current curve <NUM>, the current provided to the battery pack can be varied inversely with temperature based on an inverse functional relationship such that the battery pack can avoid an over-temperature condition.

At time <NUM>, the battery pack can be charged in a constant voltage manner. For instance, prior to time <NUM>, the battery pack may have been charged in a specified-current manner, such as a "constant current" manner where the current can nonetheless vary based on temperature of the battery pack, as described herein. Generally, however, the voltage of the battery pack is expected to increase prior to time <NUM>. At <NUM>, however, the battery pack can instead be charged in a constant voltage manner to maintain the voltage at which the battery pack is at time <NUM> (e.g., a rated voltage for the battery pack). As illustrated at time <NUM> by voltage curve <NUM> and state of charge curve <NUM>, the battery is not quite at <NUM>% state of charge. Thus, the battery can continue charging with constant voltage until time <NUM>, at which the battery completes charging. Subsequent to time <NUM>, current may still be provided to the battery to maintain a <NUM>% state of charge.

<FIG> illustrates a flow chart diagram of an example method <NUM> for charging a battery pack to avoid an over-temperature condition according to example embodiments of the present disclosure. 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. 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.

The method <NUM> can be implemented by any suitable computing device in communication with a battery pack and/or battery charger, such as battery pack <NUM> and/or battery charger <NUM> of <FIG>. As an example, some of all steps of the method <NUM> can be implemented by battery controller <NUM> of <FIG>. As another example, some or all steps of the method <NUM> can be implemented by charger controller <NUM> of <FIG>. The method <NUM> can be performed by any suitable computing structures, such as, for example, volatile and/or non-volatile computer readable media, processor(s), programmable logic circuits and/or programmable logic arrays, application-specific integrated circuits, and/or other suitable computing systems.

The method <NUM> can include, at <NUM>, obtaining a temperature measurement indicative of a temperature of at least one cell from a temperature sensor. The temperature measurement can be indicative of a temperature of the battery pack (e.g., a temperature of the at least one cell). For instance, in some embodiments, the temperature measurement can be communicated from the temperature sensor to a controller, such as a battery controller and/or charger controller. In one example embodiment, a single temperature sensor is configured to obtain a temperature measurement of one cell to determine the temperature of the battery pack. For example, the temperature measurement of a single cell can be extrapolated to represent the temperature of the battery pack. Other suitable temperature measurement configurations may be employed in accordance with example embodiments of the present disclosure.

Additionally and/or alternatively, in some embodiments, the temperature measurement may be made available to the battery charger. For instance, in some embodiments, the temperature measurement may be available at a temperature measurement terminal at the battery pack. For instance, when the battery pack is received at a device (e.g., the battery charger), the temperature measurement terminal may convey a temperature measurement signal (e.g., a digital and/or analog signal) that is descriptive of the temperature measurement to the device to which the battery pack is coupled (e.g., the battery charger). The battery charger (e.g., charger controller) may obtain the temperature measurement from the temperature measurement terminal.

The method <NUM> can include, at <NUM>, determining, based at least in part on the temperature measurement, that the temperature of the at least one cell is between a lower temperature threshold and an upper temperature threshold. For instance, the lower temperature threshold can be at a temperature at which it becomes desirable to begin reducing current to the battery pack to avoid the over-temperature condition. Generally, the lower temperature threshold can be any suitable temperature and may be a temperature that is less than (e.g., about <NUM> degrees Celsius less than) the upper temperature threshold. Furthermore, in some embodiments, the upper temperature threshold can be at an upper temperature limit, such as a temperature at which an over-temperature condition occurs. The controller can determine that the temperature of the at least one cell is between a lower temperature threshold and an upper temperature threshold in any suitable manner, such as, for example, by a threshold comparison. Additionally and/or alternatively, the determination may be performed as a result of inputting the temperature into a mathematical model, for example.

Additionally and/or alternatively, the method <NUM> can include, at <NUM>, in response to determining that the temperature of the at least one cell is between the lower temperature threshold and the upper temperature threshold, reducing a maximum charging current. For instance, reducing the maximum charging current can include reducing a maximum charging current that is requested from a battery charger (e.g., by a charging current request). According to example aspects of the present disclosure, reducing the maximum charging current can include reducing the maximum charging current based at least in part on an inverse functional relationship between the temperature measurement and the maximum charging current. For instance, the inverse functional relationship can provide that a maximum charging current will decrease as temperature of the at least one cell increases. Additionally and/or alternatively, the maximum charging current can be allowed to recover (e.g., increase) as the temperature decreases (e.g., after reducing). In some embodiments, the inverse functional relationship can be a monotonically decreasing relationship. For example, in some embodiments, the inverse functional relationship can be a linearly decreasing relationship. For example, the maximum charging current can decrease linearly with respect to increasing temperature. Other suitable functional relationships can be employed in accordance with example aspects of the present disclosure.

In some embodiments, the inverse functional relationship can be or can include a mathematical model or function. For example, a computing system can compute the maximum charging current based on a formula or mathematical model. As another example, the inverse functional relationship can be or can include a lookup table. For example, the maximum charging current can be retrieved from a lookup table where temperature is provided to the lookup table as input. Other suitable systems for utilizing an inverse function relationship (e.g., thresholding) can be employed in accordance with example aspects of the present disclosure. As one example, the maximum charging current can be determined with respect to a temperature-based current limit from a temperature-current curve. The temperature-current curve can be stored in non-transitory computer-readable media, such as, for example, flash memory, RAM, ROM, EEPROM, hard disk memory, solid state memory, and/or any other suitable memory. For instance, in some embodiments, the curve can be stored as a lookup table, mathematical relationship or model, or other suitable representation.

Additionally and/or alternatively, the method <NUM> can include, at <NUM>, controlling a battery charger based at least in part on the maximum charging current to charge the one or more cells. For instance, in some embodiments, the battery charger, such as a supply of the battery charger, can be configured to provide an amount of voltage and/or current to battery pack that is equal to or less than the maximum charging current. For instance, in some embodiments, the charger controller can adjust characteristics of one or more digital signals, such as pulse width modulated (PWM) signals, to configure an amount of current and/or voltage and/or power supplied by the battery charger (e.g., the supply). For instance, the controller can adjust the voltage and/or current at the battery pack by adjusting duty cycle, frequency/period, etc. of one or more pulse width modulation circuits at the battery charger. As another example, in some embodiments, charger controller can adjust other components of the battery charger, such as variable components, such as variable resistors, varactors, switches, etc., to configure an amount of current and/or voltage and/or power supplied by the battery charger. For example, a charger controller can be configured to adjust the power signal from the battery charger (e.g., for charging the cell(s)) based at least in part on the maximum charging current (e.g., from the battery controller and/or as determined at the charger controller) as described herein.

In some embodiments, controlling the battery charger based at least in part on the maximum charging current can include requesting, from the battery charger, the maximum charging current for charging the one or more cells. For instance, in some embodiments, the battery controller can determine a charging current request. The charging current request can specify a requested amount of current to be provided to the battery for charging the battery, such as the maximum charging current. The charging current request can be communicated to the battery charger, such as a charger controller. In some embodiments, the maximum charging current can be periodically requested from the battery charger. For instance, the maximum charging current may be determined and requested at regular intervals to ensure that the current is updated as necessary. For example, the maximum charging current can be requested in periodic intervals, such as at set time intervals, including regular intervals and/or irregular intervals, in response to stimuli, etc..

After receiving the charging current request, the charger controller can configure a battery charger (e.g., a supply) to deliver the amount of current that is specified by the charging current request to the battery pack (e.g., cells). As one example, a battery pack and/or a battery charger can include one or more charging terminals configured to provide electrical connection between the one or more cells and the battery charger, such as between the one or more cells and the supply. In some embodiments, the charging current request is periodically communicated to the battery charger. For example, the charging current request can be communicated in periodic intervals, such as at set time intervals, including regular intervals and/or irregular intervals, in response to stimuli, etc..

<FIG> illustrates a flow chart diagram of an example method <NUM> for mitigating an over-temperature condition according to example embodiments of the present disclosure. 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. 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.

The method <NUM> can include, at <NUM>, determining, based at least in part on the temperature measurement, that the temperature of the at least one cell is greater than the upper temperature threshold. For example, the controller can compare the temperature of the cell(s) to the upper temperature threshold. If the temperature meets or exceeds the upper temperature threshold, it can be desirable to halt charging the battery pack. For instance, in response to determining that the temperature of the one or more cells is greater than the upper temperature threshold, the method <NUM> can include, at <NUM>, halting charging of the battery pack. For instance, halting charging of the battery pack can include requesting a minimus current from the battery charger while charging is halted. The minimus current can be a current that is at or near zero amps, such as less than about. <NUM> amps, such as <NUM> amps. For example, halting charging of the battery pack can include communicating a halt current request to the battery charger, where the halt current request includes a request for zero amps or near-zero amps.

Claim 1:
A battery pack (<NUM>), comprising:
one or more cells (<NUM>);
at least one temperature sensor (<NUM>) configured to obtain a temperature measurement indicative of a temperature of at least one cell (<NUM>) of the one or more cells (<NUM>); and
a controller, the controller configured to be placed in signal communication with a battery charger (<NUM>);
wherein the controller is configured to perform operations, the operations comprising:
obtaining the temperature measurement from the at least one temperature sensor (<NUM>);
determining, based at least in part on the temperature measurement, that the temperature of the at least one cell (<NUM>) is between a lower temperature threshold (<NUM>) and an upper temperature threshold (<NUM>);
in response to determining that the temperature of the at least one cell (<NUM>) is between the lower temperature threshold (<NUM>) and the upper temperature threshold (<NUM>), reducing a maximum charging current, wherein reducing the maximum charging current comprises reducing the maximum charging current based at least in part on an inverse functional relationship between the temperature measurement and the maximum charging current; wherein the maximum charging current is reduced across at least a temperature-inverse region (<NUM>), and
determining, based at least in part on the temperature measurement, that the temperature of the at least one cell (<NUM>) is greater than the upper temperature threshold (<NUM>);
in response to determining that the temperature of the at least one cell (<NUM>) is greater than the upper temperature threshold (<NUM>), halting charging of the battery pack (<NUM>);
determining, subsequent to halting charging of the battery pack (<NUM>), that the temperature of the at least one cell (<NUM>) reaches the lower temperature threshold (<NUM>) within the temperature-inverse region (<NUM>); and
in response to determining that the temperature of the at least one cell (<NUM>) reaches the lower temperature threshold (<NUM>) within the temperature-inverse region (<NUM>), resuming charging of the battery pack (<NUM>) by reducing the maximum charging current based in part on the inverse functional relationship between temperature measurement and the maximum charging current; and
controlling the battery charger (<NUM>) based at least in part on the maximum charging current to charge the one or more cells (<NUM>).