CN1655387B - System and method for battery charging - Google Patents

Abstract

A system and method for battery protection. In some aspects, a battery pack includes a housing, a cell supported by the housing, a circuit supported by the housing and operable to control a function of the battery pack, and a heat sink in heat transfer relationship with the circuit and operable to dissipate heat from the circuit.A system and method for battery protection. In some aspects, a method of conducting an operation including a battery pack, includes the acts of monitoring a first battery pack condition at a first monitoring rate, determining when a second battery pack condition reaches a threshold, after the second battery pack condition reaches the threshold, monitoring the first battery pack condition at a second monitoring rate, the second monitoring rate being different than the first monitoring rate. In some aspects, a method of conducting an operation including a battery, the battery including a cell having a voltage, power being transferable between the cell and the electrical device, a controller operable to control a function of the battery pack, the controller being operable with a voltage at least one of equal to and greater than an operating voltage threshold, the cell being operable to selectively supply voltage to the controller, includes the act of enabling the controller to operate when the voltage supplied by the cell is below the operating voltage threshold.

Description

System and method for battery charging

field of invention

This patent application claims serial numbers 60/428,358 filed November 22, 2002, 60/428,450 filed November 22, 2002, and 60/428,452 filed November 22, 2002 , previously filed unauthorized U.S. Provisional Patent Applications Serial No. 60/400,692, filed January 17, 2003 and Serial No. 60/440,693, filed January 17, 2003, and A previously filed unpatented U.S. Provisional Patent Application, entitled "System and Method for Battery Protection," Attorney Docket No. 066042-9536-00, filed on 11.19, 2003, and titled Interest in the claims of a previously filed unpatented U.S. Provisional Patent Application for "System and Method for Charging a Battery," Attorney Docket No. 066042-9538-00, the entire contents of which are hereby incorporated by reference . U.S. Patent Application entitled "System and Method for Battery Protection," Attorney Docket No. 066042-9536-01, filed November 20, 2003, is also incorporated herein by reference.

technical field

The present invention relates generally to a system and method for charging a battery, and more particularly, to a system and method for charging a battery of a power tool.

Background technique

Cordless power tools are often powered by portable battery packs. These battery packs come in different battery chemistries and nominal voltage ranges, and can be used to power a variety of tools and electrical equipment. Typically, the battery chemistry of a power tool battery is either nickel cadmium (“NiCd”) or nickel metal hydride (“NiMH”). The nominal voltage of the battery pack is generally in the range between about 2.4V to 24V.

Contents of the invention

Some battery chemistries (eg, lithium ("Li"), lithium-ion ("Li-ion"), and other lithium-based chemistries) require precise charging schemes and operations for charging and controlled discharging. Inadequate charging schemes and uncontrolled discharging schemes may generate excessive built-in heat, overcharging conditions and/or overdischarging conditions. These conditions and built-in factors can cause irreversible damage to the battery and severely impact the capacity of the battery.

The present invention provides systems and methods for battery charging. In some constructions and in some aspects, the present invention provides a battery charger capable of fully charging a variety of battery packs with different battery chemistries. In some constructions and in some aspects, the present invention provides a battery charger capable of fully charging lithium-based batteries, such as lithium-cobalt batteries, lithium-manganese batteries, and spinel batteries, among others. In some constructions and in some aspects, the present invention provides a battery charger capable of charging lithium chemistry-based battery packs at different nominal voltages or within different nominal voltage ranges. In some constructions and in some aspects, the present invention provides a battery charger with multiple charging modules that perform based on different battery conditions. In some constructions and in some aspects, the present invention provides systems and methods for charging lithium-based batteries by applying constant current pulses. The time between pulses and the length of the pulses may be increased or decreased by the battery charger according to specific battery characteristics.

The independent features and independent advantages of the present invention will be clearly understood by those skilled in the art from the following detailed description, claims and elucidation of the accompanying drawings.

Description of drawings:

Figure 1 is a perspective view of a battery;

Figure 2 is another perspective view of a battery, like the battery shown in Figure 1;

Figure 3 is a perspective view of a battery, like the battery shown in Figure 1, physically and electrically connected to a battery charger;

Figure 4 is a schematic diagram of a battery electrically connected to a battery charger, like the battery and battery charger shown in Figure 3;

Figures 5a and 5b are flowcharts illustrating the operation of a battery charger employing aspects of the present invention, like the battery charger shown in Figure 3;

Figure 6 is a flow diagram illustrating a first module that can be implemented on a battery charger like the battery charger shown in Figure 3 employing aspects of the present invention;

Figure 7 is a flow diagram illustrating a second module that can be implemented on a battery charger like the battery charger shown in Figure 3 employing aspects of the present invention;

Figure 8 is a flow diagram illustrating a third module that can be implemented on a battery charger like the battery charger shown in Figure 3 employing aspects of the present invention;

Figure 9 is a flow diagram illustrating a fourth module that can be implemented on a battery charger like the battery charger shown in Figure 3 employing aspects of the present invention;

Figure 10 is a flow diagram illustrating a fifth module that can be implemented on a battery charger like the battery charger shown in Figure 3 employing aspects of the present invention;

Figure 11 is a flow diagram illustrating a sixth module that can be implemented on a battery charger like the battery charger shown in Figure 3 employing aspects of the present invention;

Figure 12 is a flow diagram illustrating a charging algorithm that can be implemented on a battery charger like the battery charger shown in Figure 3 employing aspects of the present invention;

13 is a schematic diagram of a battery electrically connected to a battery charger.

14A-B are views of other configurations of batteries.

15A-B are perspective views of the electrical and physical connections to a power tool battery, such as the one shown in FIGS. 1, 2 and 14A-B.

FIG. 16 is a schematic diagram of charging current to a battery.

Figure 17 is another schematic diagram of a battery.

Before any embodiments of the invention are illustrated in detail, it is to be understood that the invention is not limited in application to the details of construction and the arrangement of components described and illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is also to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. As used herein, "comprising", "comprising" or "having" and variations thereof are meant to surround the item listed below and its equivalents as well as additional items.

Detailed ways

The cell or battery pack 20 is shown in FIGS. 1 and 2 . The battery 20 is configured to transmit power to and receive power from one or more electrical devices, for example, a power tool 25 (as shown in FIGS. 15A-B ) and/or a battery charger 30 (as shown in FIG. 3 and 4). In some constructions and some aspects, the battery 20 can be of any battery chemistry, for example, lead-acid, nickel cadmium (“NiCd”), nickel metal hydride (“NiMH”), lithium (“Li”), lithium-ion ( "L-ion"), other lithium-based chemistries, and other rechargeable battery chemistries. In some constructions and some aspects, the battery 20 is capable of providing a high discharge current to an electrical device, such as a power tool with a high current discharge rate. In the illustrated construction, battery 20 has lithium, lithium-ion, and other lithium-based chemistries, and provides an average discharge current equal to or greater than about 2OA. For example, in the illustrated configuration, cell 20 can have lithium cobalt ("Li-Co"), lithium manganese ("Li-Mn") spinel, or Li-Mn nickel chemistry.

In some constructions and some aspects, the battery 20 can also have any nominal voltage, for example, a nominal voltage in the range of about 9.6V to about 50V. In some constructions (eg, FIGS. 1-3 ), battery 20 has a nominal voltage of approximately 21V, for example. In another configuration (eg, FIG. 14), the battery 20A has a nominal voltage of about 28V. It should be appreciated that in other configurations, battery 20 may have other nominal voltages within other nominal voltage ranges.

The battery 20 includes a housing 35 that provides terminal support 40 . Battery 20 further includes one or more battery terminals supported by terminal support 40 and connectable to electrical equipment, such as power tool 25 and/or battery charger 30 . In some constructions, such as the construction shown in FIG. 4 , the battery 20 includes a positive battery terminal 45 , a negative battery terminal 50 and an inductive battery terminal 55 . In some constructions, battery 20 includes more or fewer terminals than shown in the figures.

Battery 20 includes one or more battery cells 60, each having a chemistry and a nominal voltage. In some constructions, battery 20 has a Li-ion battery chemistry, a nominal voltage of approximately 18V or 21V, and includes five battery cells. In some constructions, each battery cell 60 has a chemistry of Li ions, and each battery cell 60 has substantially the same nominal voltage, eg, about 3.6V or about 4.2V.

In some constructions and some aspects, battery 20 includes identification circuitry or components electrically connected to one or more battery terminals. In some constructions, an electrical device (e.g., battery charger 30 (shown in FIGS. 3 and 4 )) will "read" or receive input based on identifying circuits and components in order to determine one or more battery characteristics . In some constructions, the battery characteristics will include, for example, the nominal voltage of the battery 20 , the temperature of the battery 20 and/or the chemistry of the battery 20 .

In some constructions and some aspects, battery 20 includes a control device, microcontroller, microprocessor, and controller electrically connected to one or more battery terminals. The controller communicates with the electrical device (such as the battery charger 30) and provides information to the device relating to one or more battery characteristics or conditions, for example, the nominal voltage of the battery 20, the voltage of a single cell, the temperature of the battery 20 and/or or battery 20 chemistry. In some constructions, such as that shown in FIG. 4 , the battery 20 includes an identification circuit 62 with a microprocessor or controller 64 .

In some constructions and some aspects, battery 20 includes a temperature sensing device or thermistor. Thermistors are provided and placed within the battery 20 to sense the temperature of one or more battery cells or the temperature of the entire battery 20 . In some constructions, such as the construction shown in FIG. 4 , the battery 20 includes a thermistor 66 . In the illustrated construction, thermistor 66 is included in identification circuit 62 .

As shown in FIGS. 3 and 4 , a battery 20 is also provided for connection to an electrical device, such as a battery charger 30 . In some constructions, battery charger 30 includes housing 70 . The case 70 provides a connection portion 75 to which the battery 20 is connected. Connection portion 75 includes one or more electrical device terminals to electrically connect battery 20 to battery charger 30 . The terminals included in the battery charger 30 are configured to match the terminals included in the battery 20 and transmit and receive energy and information from the battery 20 .

In some configurations, such as the configuration shown in FIG. 4 , the battery charger 30 includes a positive terminal 80 , a negative terminal 85 and a sense terminal 90 . In some constructions, the positive terminal 80 of the battery charger 30 is configured to match the positive battery terminal 45 . In some constructions, the negative terminal 85 and the sense terminal 90 of the battery charger are arranged to match the negative battery terminal 50 and the sense battery terminal 55 respectively.

In some constructions and some aspects, the battery charger 30 also includes a charging circuit 95 . In some constructions, charging circuit 95 includes a control device, microcontroller, microprocessor or controller 100 . The controller 100 controls power transmission between the battery 20 and the battery charger 30 . In some constructions, the controller 100 controls the transfer of information between the battery 20 and the battery charger 30 . In some constructions, the controller 100 identifies and/or determines one or more characteristics and conditions of the battery 20 based on signals received from the battery 20 . Also, the controller 100 can control the operation of the charger 30 based on the identification characteristic of the battery 20 .

In some constructions and some aspects, the controller 100 includes various timers, backup timers and counters and/or is capable of performing various timing and counting functions. The timer, backup timer and counter are used and controlled by the controller 100 in various charging steps and/or modules. This timer, alternate timers and counters are discussed below.

In some constructions and some aspects, battery charger 30 includes a display screen and indicator 110 . The indicator 110 notifies the user of the status of the battery charger 30 . In some constructions, the indicator 110 can inform the user of the different stages of charging, charging modes, or charging modules that are beginning and/or ending during the charging operation. In some constructions, the indicator 110 includes a first light emitting diode (“LED”) 115 and a second LED 120. In the illustrated structure, the first and second LEDs 115 and 120 are LEDs of different colors. For example, the first LED 115 is a red LED and the second LED 120 is a green LED. In some constructions, the controller 100 activates and controls the indicator 110 . In some constructions, the indicator 110 is placed on or included in the housing 70 such that the indicator is visible to the user. The display may also include indicators showing the percentage of charge, time remaining, etc. In some constructions, the display or indicator 110 may include fuel specifications provided by the battery 20 .

The battery charger 30 is adapted to receive a power input from a power source 130 . In some constructions, the power source 130 is an approximately 120-V AC, 60-Hz signal. In other constructions, the power supply 130 is, for example, a constant current source.

In some constructions and some aspects, battery charger 30 is capable of charging a variety of rechargeable batteries having different battery chemistries and different nominal voltages as described below. For example, in an exemplary implementation, battery charger 30 is capable of charging a first battery with a battery chemistry of NiCd and a nominal voltage of approximately 14.4V, and a battery chemistry of Li-ion with a nominal voltage of approximately 18V. A second battery at nominal voltage and a third battery with a Li-ion battery chemistry and a nominal voltage of approximately 28V were charged. In another exemplary implementation, battery charging 30 is capable of charging a first Li-ion battery having a nominal voltage of approximately 21V and a second Li-ion battery having a nominal voltage of approximately 28V. In this exemplary implementation, the battery charger 30 is capable of identifying the nominal voltage of each battery 20, and thus, as described below, the battery charger 30 can scale a particular threshold, or alter the voltage based on the nominal voltage of the battery Read in and measure (used during charging).

In some constructions, battery charger 30 is capable of identifying the nominal voltage of battery 20 by "reading" an identification element included in battery 20 or by receiving a signal from, for example, a battery microprocessor or controller. In some constructions, the battery charger 30 may include acceptable nominal voltage ranges for the batteries 20 that the various chargers 30 can identify. In some constructions, the range of acceptable nominal voltages can include a range from about 8V to about 50V. In other constructions, the range of acceptable nominal voltages can include a range from about 12V to about 28V. In a further construction, the battery charger 30 is capable of identifying a nominal voltage approximately equal to or greater than 12V. In still a further construction, the battery charger 30 is capable of identifying a nominal voltage of about equal to or lower than 30V.

In further constructions, battery charger 30 is capable of identifying a range of values that includes the nominal voltage of battery 20 . For example, rather than identifying the first battery 20 as having a nominal voltage of about 18V, the battery charger 30 can identify that the nominal voltage of the first battery 20 is within a range of, for example, about 18V to 22V or about 16V to about 24V. In further constructions, the battery charger 30 is also capable of identifying other battery characteristics, such as the number of battery cells, battery chemistry, and the like.

In other constructions, the charger 30 is capable of identifying the nominal voltage of any battery 20 . In these configurations, the battery 30 is capable of charging any nominal voltage battery 20 by adjusting and calibrating certain thresholds according to the nominal voltage of the battery 20 . Also in these configurations, each battery 20, regardless of its nominal voltage, may receive approximately equal charge current magnitudes for approximately equal amounts of time (eg, if each battery 20 is approximately fully discharged). The battery charger 30 can either adjust or calibrate a threshold (discussed below) or a metric based on the nominal voltage of the battery 30 being charged.

For example, battery charger 30 may identify a first battery having a nominal voltage of approximately 21V and 5 cells. Throughout the charging process, the battery charger 30 modifies the metric sampled by each charger 30 (eg, battery voltage) to arrive at a per-cell metric. That is, charger 30 divides each battery voltage measure by five (eg, five cells) to get an approximate average voltage for each cell. Therefore, all thresholds included in the battery charger 30 may be associated with a per-cell metric. Also, the battery charger 30 may recognize a second battery having a nominal voltage of approximately 28V and 7 cells. Similar to the operation of the first battery, the battery charger 30 modifies each voltage metric to obtain a per-cell metric. All thresholds included in the battery charger 30 are again associated with a per-unit metric. In this example, the battery charger 30 can use the same thresholds to monitor and disable charging of the first and second batteries, enabling the battery charger 30 to charge many batteries over a wide range of nominal voltages.

In some constructions and some aspects, the charging scheme or method by which the battery charger 30 charges the battery 20 is based on the temperature of the battery 20 . In some constructions, the battery charger 30 provides charging current to the battery 20 while periodically detecting and monitoring the temperature of the battery 20 . If the battery 20 does not include a microprocessor and controller, the battery charger 30 periodically measures the resistance of the thermistor after a predetermined period of time. If the battery 20 includes a microprocessor and a controller, such as the controller 64, then the battery charger either: 1) periodically interrogates the controller 64 to determine the battery temperature and/or whether the battery temperature is outside the proper operating range; Or 2) Wait to receive a signal from controller 64 indicating that the battery temperature is not within the proper operating range (discussed below).

In some constructions and some aspects, the charging scheme and method by which the battery charger 30 charges the battery 20 is based on the current voltage of the battery 20 . In some constructions, the battery charger 30 provides charging current to the battery 20, while after a predetermined period of time, when current is provided to the battery 20 and/or when current is not provided (as will be described below) ) regularly detects and monitors the battery voltage. In some constructions, the charging scheme and method by which the battery charger 30 charges the battery 20 is based on both the temperature and the current voltage of the battery 20 . Also, charging schemes can be based on individual cell voltages.

Once the battery temperature and/or battery voltage exceeds predetermined thresholds or is not within a suitable operating range, the battery charger 30 interrupts the charging current. The battery charger 30 continues to periodically detect or monitor the battery temperature/voltage or wait to receive a signal from the controller 64 indicating that the battery temperature/voltage is within the adapted operating range. The battery charger 30 may resume providing charging current to the battery 20 when the battery temperature/voltage is within the adapted operating range. The battery charger 30 continues to monitor the battery temperature/voltage and continues to interrupt and resume charging current based on the detected battery temperature/voltage. In some constructions, the battery charger 30 terminates charging after a predetermined time period or when the battery capacity reaches a predetermined threshold. In other constructions, charging is terminated when the battery 20 is removed from the battery charger 30 .

In some constructions and some aspects, battery charger 30 includes methods of operation for charging multiple batteries, such as batteries 20 having different chemistries and/or nominal voltages. An example of such an operation 200 is shown in Figures 5a and 5b. In some constructions and some aspects, the battery charger 30 includes charging a lithium-based battery, such as a battery with a Li-Co chemistry, a Li-Mn spinel chemistry, a Li-Mn nickel chemistry, or other similar batteries. method of operation. In some constructions and some aspects, the charging operation 200 includes various modules for performing different functions corresponding to different battery conditions and/or battery characteristics.

In some constructions and some aspects, the method of operation 200 includes means for interrupting charging based on abnormal and/or normal battery conditions. In some constructions, the charging operation 200 includes a bad group module, such as the bad group module shown in flow 205 of FIG. 6 , and/or a temperature out-of-range module, such as the temperature out-of-range module shown in flow 210 of FIG. 7 . In some constructions, the battery charger 30 enters a bad group module in order to terminate charging based on abnormal battery voltage, abnormal cell voltage, and/or abnormal battery capacity. In some constructions, the battery charger 30 enters the temperature out of range module 210 in order to terminate charging based on the abnormal battery temperature and/or one or more abnormal battery cell temperatures. In some constructions, charging operation 200 includes more or fewer modules that terminate charging based on more or fewer battery conditions than discussed above and below.

In some constructions and some aspects, charging operation 200 includes multiple modes or modules for charging battery 20 based on various battery conditions. In some configurations, the charging operation 200 includes: a continuous supplementary charging module, such as the continuous supplementary charging module shown in the process 215 of FIG. 8 ; a stepped charging module, such as the stepped charging module shown in the process 220 of FIG. 9 ; A fast charging module, such as the fast charging module shown in the process 225 in FIG. 10 ; and/or a maintaining charging module, such as the maintaining charging module shown in the process 230 in FIG. 11 .

In some constructions and some aspects, each charging module 215 - 230 is selected by the controller 100 during charging operation 200 based on a particular battery temperature range, a particular battery voltage range, and/or a particular battery capacity range. In some constructions, each module 215 - 230 is selected by the controller 100 based on the battery characteristics shown in FIG. 1 . In some constructions, the condition "battery temperature" or "battery temperature" may include the temperature of the battery considered as a whole (that is, battery cells, battery assemblies, etc.) and/or the temperature of individual or collectively considered battery cells. temperature. In some constructions, each charging module 215-230 may be based on the same charging scheme or algorithm, eg, full charge current, as discussed below.

Operations for charging lithium-based batteries

Table 1

In some cases and aspects, the charging current applied to the battery 20 during the continuous replenishment of the charging module 215 includes applying a full charging current (e.g., "I") to the battery 20 for a first time period (e.g., ten seconds). , and then suspend the full charge current for a second time period (eg, 50 seconds). In some constructions, the full charge current is a pulse of charge current at approximately a predetermined magnitude. In some constructions, the battery charger 30 only enters the continuous supplemental charging module 215 if the battery voltage is less than the first predetermined voltage threshold V1.

In some cases and aspects, the charging current applied to the battery 20 during the fast charging module 225 includes applying a full charging current to the battery 20 for a first time period (e.g., 1 second) and thereafter for a second time period. (eg, 50 milliseconds) to suspend the full charge current. In some constructions, the controller 100 sets the backup timer to a first predetermined time limit, eg, approximately two hours. In these configurations, the battery charger 30 will not perform the fast charging module 225 for a predetermined time limit in order to avoid battery damage. In other constructions, the battery charger will shut down (eg, stop charging) when a predetermined time limit expires.

In some constructions, the battery charger 30 only operates if the battery voltage is within a range from a first voltage threshold V1 to a second predetermined voltage threshold V2 and the battery temperature is within a range from a second battery temperature threshold T2 to a third predetermined voltage threshold V2. Enter the fast charging mode when the battery temperature threshold is within the range of T3. In some constructions, the second voltage threshold V2 is greater than the first voltage threshold V1, and the third temperature threshold T3 is greater than the second temperature threshold T2.

In some constructions and some aspects, the charging current applied to the battery 20 during the step charging module 220 includes applying the charging current of the fast charging mode 225 to the battery 20, but with one minute charging (“ON”), one minute Duty cycle with charging suspended ("OFF"). In some constructions, the controller 100 sets the backup timer to a second predetermined time limit, such as approximately four hours. In these configurations, the battery charger 30 will not execute the stepped charging module 220 for a predetermined time limit in order to avoid battery damage.

In some constructions, the battery charger 30 only operates if the battery voltage is comprised within a range from the first voltage threshold V1 to the second voltage threshold V2, and the battery temperature is within a range from the first temperature threshold T1 to the second temperature threshold T2. Enter the stepped charging module if it is within the range. In some constructions, the second voltage threshold V2 is greater than the first voltage threshold V1 , and the second temperature threshold T2 is greater than the first temperature threshold T1 .

In some constructions and some aspects, the charging current applied to the battery 20 during maintaining the module 230 includes applying the full charging current to the battery 20 only when the battery voltage is within a certain predetermined threshold range. In some configurations, the threshold is approximately 4.05-V/cell +/- 1% per cell. In some constructions, the battery charger 30 only operates if the battery voltage is comprised in the range from the second voltage threshold V2 to the third voltage threshold V3, and the battery temperature is in the range from the first temperature threshold T1 to the third temperature threshold T3 Enter the hold module 230 within the case.

In some constructions and some aspects, the controller 100 implements various charging modules 220-230 based on different battery conditions. In some constructions, each charging module 220-230 includes the same charging algorithm (eg, an algorithm for applying the full charging current). However, each charging module 220-230 implements the iterative or combined charging algorithm differently. An example of a charging algorithm is the charging current algorithm shown in flow 250 of Figure 12, discussed below.

As shown in FIGS. 5 a and 5 b , charging operation 200 begins when a battery, such as battery 20 , is inserted or electrically connected to battery charger 30 at step 305 . At step 310 , the controller 100 determines whether a power source, such as a steady input of the power source 130 , is applied or connected to the battery charger 30 . As shown in Figure 5a, the same operation applies if power is still provided after the battery 20 is electrically connected to the battery charger 30 (that is, step 305 is followed by step 310).

If the controller 100 determines that there is no steady power input applied, then the controller 100 does not activate the indicator 110 at step 315 and does not apply charging to the battery 20 . In some constructions, the battery charger 30 induces a small discharge current at step 315 . In some constructions, the discharge current is less than about 0.1 mA.

If at step 310 the controller 100 determines that a stable power input is applied to the battery charger 30 , then the operation 200 proceeds to step 320 . In step 320, the controller 100 determines whether all terminal connections between the battery terminals 45, 50 and 55 and the battery charger terminals 80, 85 and 90 are stable. If the connection is unstable at step 320 , the controller 100 proceeds to step 315 .

If at step 320 the connection is stable, at step 325 the controller 100 identifies the chemistry of the battery 20 via the sensing terminal 55 of the battery 20 . In some constructions, a resistive sense lead from the battery 20, as sensed by the controller 100, indicates that the battery 20 has a chemistry of either NiCd or NiMH. In some constructions, the controller 100 will measure the resistance of the resistive sense lead to determine the chemistry of the battery 20 . For example, in some constructions, the battery 20 chemistry is NiCd if the resistance of the resistive sense lead is within a first range. If the resistance of the resistive sense lead is within the second range, the battery 20 chemistry is NiMH.

In some constructions, the NiCd battery and the NiMH battery are charged by the battery charger using a single charging algorithm different from the charging algorithm implemented for batteries with lithium-based chemistries. In some configurations, the single charging algorithm for NiCd and NiMH batteries is, for example, the charging algorithm for the presence of NiCd/NiMH batteries. In some constructions, battery charger 30 uses a single charging algorithm for charging NiCd batteries and NiMH batteries, but stops charging NiCd batteries using a different termination scheme than terminating charging NiMH batteries. In some constructions, the battery charger 30 responds to a negative change in battery voltage (eg, ) is detected by the controller 100 to terminate charging of the NiCd battery. In some constructions, battery charger 30 may be used for a period of time (eg, ) terminates charging of the NiMH battery when the battery temperature change reaches and exceeds a predetermined termination threshold.

In some configurations, NiCd and/or NiMH batteries are charged using a constant current algorithm, for example, battery charger 30 may include the same charge for charging different batteries with different chemistries, such as NiCd, NiMH, Li-ion, and the like. circuit. In an exemplary configuration, charger 30 can use a charging circuit to apply the same full charge current to NiCd and NiMH batteries, and Li-ion batteries use a constant current algorithm instead of pulse charging. In another exemplary configuration, the battery charger 30 is capable of scaling the full charge current through the charging circuit based on the battery chemistry.

In other constructions, the controller 100 does not determine the precise chemistry of the battery 20 . Instead, the controller 100 implements a charging module capable of efficiently charging NiCd batteries and NiMH batteries.

In other constructions, the resistance of the sense lead can indicate that the battery 20 has a lithium-based chemistry. For example, if the sense lead resistance is within the third range, then the battery 20 chemistry is lithium based.

In some constructions, a serial communication link established between battery charger 30 and battery 20 via sensing terminals 55 and 90 indicates that battery 20 has a lithium-based chemistry. If a serial communication link is established at step 320 , the microprocessor and controller (such as controller 64 ) in battery 20 send information related to battery 20 to controller 100 in battery charger 30 . The information transferred between the battery 20 and the battery charger 30 can include: battery chemistry, nominal battery voltage, battery capacity and battery temperature, individual cell voltages, number of charge cycles, number of discharge cycles, protection circuits and The state of the network (eg, active, disabled, enabled, etc.), etc.

At step 330, the controller 100 determines whether the chemistry of the battery 20 is lithium-based. If at step 330 the controller 100 determines that the battery 20 has a NiCd or NiMH chemistry, then at step 335 operation 200 continues with the NiCd/NiMH charging algorithm.

If the controller 100 determines at step 330 that the battery 20 has a chemistry that is lithium-based, the operation 200 proceeds to step 340 . At step 340, the controller 100 resets any battery protection circuitry, eg, switches included on the battery 20 and determined via the communication link to the nominal voltage of the battery 20 . At step 345, the controller 100 sets the charger's analog-to-digital converter ("A/D") to an appropriate level based on the nominal voltage.

In step 350 , the controller 100 measures the current voltage of the battery 20 . Once the measurement is made, the controller 100 determines at step 355 whether the voltage of the battery 20 is greater than 4.3 V/cell. If the battery voltage measured at step 355 is greater than 4.3 V/cell, operations 200 continue to the bad group module 206 at step 360 . Bad group module 205 will be discussed below.

If the battery voltage is not greater than 4.3V/cell at step 355, then the controller 100 measures the battery temperature at step 365 and determines whether the battery temperature is below -10 degrees Celsius or above 65 degrees Celsius at step 370. If the battery temperature is below -10 degrees Celsius or above 65 degrees Celsius at step 370 , then operations 200 proceed to the temperature out of range module 210 at step 375 . The temperature out of range module 210 will be discussed below.

If the battery voltage temperature is not below -10 degrees Celsius or above 65 degrees Celsius at step 370, then the controller 100 determines whether the battery temperature is between -10 degrees Celsius and 0 degrees Celsius at step 380 (as shown in Figure 5b). If at step 380 the battery temperature is between -10 degrees Celsius and 0 degrees Celsius. Operation 200 then proceeds to step 385 where controller 100 determines whether the battery voltage is less than 3.5V/cell. If the battery voltage is less than 3.5 V/cell, operations 200 continue with the continuous supplemental charging module 215 at step 390 . The continuous supplemental charging module 215 will be discussed below.

If the battery voltage is not less than 3.5V/cell at step 385, the controller 100 determines whether the battery voltage is included in a voltage range from 3.5V/cell to 4.1V/cell at step 395. If the battery voltage is not included in the voltage range from 3.5 V/cell to 4.1 V/cell at step 395 , then operations 200 continue with the hold module 230 at step 400 . Hold module 230 will be discussed below.

If the battery voltage is included in the voltage range from 3.5 V/cell to 4.1 V/cell at step 395 , the controller 100 clears a counter, such as a charge counter, at step 405 . Once the charge counter is cleared at step 405 , operations 200 proceed to step charging module 220 at step 410 . The stepped charge module 220 and charge counter will be discussed below.

Returning to step 380 , if the battery temperature is not included in the range of -10 degrees Celsius and 0 degrees Celsius, the controller 100 determines whether the battery voltage is less than 3.5V/cell in step 415 . If the battery voltage is less than 3.5 V/cell at step 415 , then operation 200 continues to the continuous supplemental charging module 215 at step 420 .

If the battery voltage is not less than 3.5V/cell at step 415, the controller 100 determines whether the battery voltage is included in a voltage range from 3.5V/cell to 4.1V/cell at step 425. If the battery voltage is not included in the voltage range from 3.5 V/cell to 4.1 V/cell, then operation 200 proceeds to hold module 230 at step 430 .

If the battery voltage is included in the voltage range from 3.5 V/cell to 4.1 V/cell at step 425 , the controller 100 clears a counter, such as a charge counter, at step 435 . Once the counter is cleared at step 435 , operations 200 proceed to the fast charge module 225 at step 440 . The fast charging module 225 will be discussed below.

FIG. 6 is a flowchart illustrating the operation of the bad group module 205 that begins when the main charging operation 200 enters the bad group module 205 at step 460 . The controller 100 interrupts the charging current at step 465 and activates the indicator 110 , such as a first LED, at step 470 . In the shown configuration, the controller 100 controls the first LED to blink at a frequency of about 4 Hz. Once indicator 110 is activated in step 470, module 205 stops in step 475 and operation 200 may also stop.

FIG. 7 is a flowchart illustrating the operation of the temperature out of range module 210 . Operation of the module 210 begins when the main charging operation 200 enters a temperature exceeding the module 210 at step 490 . Controller 100 interrupts the charging current at step 495 and activates indicator 110 , such as a first LED, at step 500 . In the shown configuration, the controller 100 controls the first LED to blink at a frequency of about 1 Hz to indicate to the user that the battery charger 30 is currently in the temperature out-of-range module 210 . Once the indicator 110 is activated at step 500, operation 200 exits the module 210 and continues with operation 200 to the remaining operations.

FIG. 8 is a flow diagram illustrating the continuous supplemental charging module 215 . Operation of the module 215 begins at step 520 when the main charging operation 200 enters the continuous supplemental charging module 215 . The controller 100 activates the indicator 110 at step 525, such as the first LED 115, to indicate to the user that the battery charger 30 is currently charging the battery 20. In the configuration shown, the controller 100 activates the first LED 115 to display a constant on state.

Once the indicator 110 is activated at step 525, the controller 110 initializes a counter, such as a continuous top-up charge count counter, at step 520. In the configuration shown, the continuous top-up charge count counter has a count limit of twenty.

At step 540, the controller 100 begins applying ten one-second ("1-s") (ten one) full current pulses to the battery 20, and then pauses charging for fifty seconds ("50-s"). In some configurations, there are 50-ms intervals between 1-s pulses.

At step 545, the controller 100 begins measuring the battery voltage when a charging current is applied to the battery 20 (eg, a switch-on current) to determine whether the battery voltage exceeds 4.6V/cell. If at step 545 the battery voltage exceeds 4.6V/cell during the current on time, module 215 proceeds to the bad group module 205 at step 550 and will stop at step 552 . If the battery voltage does not exceed 4.6 V/cell during the current on time at step 545, the current controller 100 measures the battery temperature and battery voltage when the charging current is not applied to the battery 20 at step 555 (e.g., the current on time). .

In step 560, the controller 100 determines whether the battery temperature is in a range below 10 degrees Celsius or above 65 degrees Celsius. If at step 560 the battery temperature is below 10 degrees Celsius or above 65 degrees Celsius, then module 215 proceeds to the temperature out of range module 210 at step 565 and will stop at step 570 . If at step 560, the battery temperature is not below -10 degrees Celsius or above 65 degrees Celsius, then the controller 100 determines at step 575 whether the battery voltage is included in the range of 3.5V/cell to 4.1V/cell.

If the battery voltage is included in the range of 3.5V/cell to 4.1V/cell at step 575, then the controller 100 determines whether the battery temperature is included in the range of -10 degrees Celsius to 0 degrees Celsius at step 580. If at step 580 the battery temperature is included within the range of -10 degrees Celsius to 0 degrees Celsius, then module 215 proceeds to step charging module 220 at step 585 . If at step 585 the battery temperature is not included within the range of -10 degrees Celsius to 0 degrees Celsius, then module 215 proceeds to the fast charging module 225 at step 590 .

If at step 575 the battery voltage is not included in the range of 3.5 V/cell to 4.1 V/cell, then the controller increments the continuous top-up charge count counter at step 595 . At step 600, the controller 100 determines whether the continuous top-up charge count counter is equal to a counter limit, such as twenty in this example. If the counter is not equal to the counter limit at step 600 , module 215 proceeds to step 540 . If the counter is indeed equal to the counter limit at step 600 , then module 215 proceeds to the bad group module 205 at step 605 and will stop at step 610 .

FIG. 9 is a flowchart showing the step charging module 220 . Operation of the module 220 begins at step 630 when the main charging operation 200 enters the stepped charging module 220 . The controller 100 activates the indicator 110, such as the first LED 115, at step 635 to indicate to the user that the battery charger 30 is currently charging the battery 20. In the configuration shown, the controller 100 activates the first LED 115 so that it appears to be in a constant on state.

At step 640, the controller 100 starts a first timer or a charge start timer. In the configuration shown, the charge start timer counts down from one minute. The module 220 proceeds to the charging current algorithm 250 at step 645 . Once the charge current algorithm 250 is executed, the controller 100 determines at step 650 whether the charge count is equal to a count limit, eg, 7200 . If at step 650 the charge count is equal to the count limit, module 220 proceeds to bad group module 205 at step 655 and module 220 will stop at step 660 .

If the charge count is not equal to the count limit at step 650, the controller 100 determines at step 665 whether the wait time between current pulses (discussed below) is greater than or equal to a first wait time threshold, eg, two seconds. If the waiting time is greater than or equal to the first waiting time threshold at step 665, the controller 100 activates the indicator 110 at step 670, for example, turning off the first LED 115 and activating the second LED 120 to blink at a frequency of about 1 Hz. If the latency is not greater than or equal to the first latency threshold at step 665, module 220 proceeds to step 690, which will be discussed below.

Once the indicator 110 is activated at step 670, the controller 100 determines at step 675 whether the wait time between current pulses is greater than or equal to a second wait time threshold, eg, fifteen seconds. If the waiting time is greater than or equal to the second waiting time threshold at step 675, the controller 100 changes the indicator 110 at step 680, such as activating the second LED 120 so that the second LED 120 shows a normally on state. The module 220 then proceeds to the hold module 230 at step 685 .

At step 675, if the waiting time is not greater than or equal to the second waiting time threshold, the controller 100 determines at step 690 whether the battery temperature is greater than 0 degrees Celsius. If at step 695 the battery temperature is greater than 0 degrees Celsius, the module 220 proceeds to the fast charging module 225 at step 695 . If the battery temperature is not greater than 0 degrees Celsius at step 690 , the controller 100 determines whether the charge start timer has expired at step 700 .

If the charge start timer has not expired at step 700 , then module 220 proceeds to the charge current algorithm at step 645 . If the charge start timer expires at step 700 , the controller 100 activates a second timer or charge off timer at step 705 and suspends charging. At step 710, the controller 100 determines whether the charge off timer has expired. If the charge off timer has not expired at step 710 , the controller 100 waits at step 715 for a predetermined amount of time and then returns to step 710 . If the charge off timer expires at step 710, the module 220 returns to step 640 to start the charge start timer again.

FIG. 10 is a flowchart illustrating the fast charging module 225 . Operation of module 225 begins when main charging operation 200 enters fast charging module 220 at step 730 . The controller 100 activates the indicator 110, such as the first LED 115, at step 735 to indicate to the user that the battery charger 30 is currently charging the battery 20. In the configuration shown, the controller 100 activates the first LED 115 so that it displays a normally on state.

The module 225 proceeds to the charging current algorithm 250 at step 740 . Once the charge current algorithm 250 is executed, the controller 100 determines at step 745 whether the charge count is equal to the count limit (eg, 7200). If the charge count is equal to the count limit at step 650 , the module 220 proceeds to the bad group module 205 at step 750 and the module 220 will stop at step 755 .

If the charge count is not equal to the count limit at step 745, the controller 100 determines whether the wait time between current pulses is greater than or equal to a first wait time threshold (eg, two seconds) at step 760 . If the waiting time is greater than or equal to the first waiting time threshold at step 760, the controller activates the indicator 110 at step 765, for example, turning off the first LED 115 and activating the second LED 120 to blink at a frequency of about 1 Hz. If at step 765 the wait time is not greater than and equal to the first wait time threshold, module 225 proceeds to step 785, which will be discussed below.

Once the indicator 110 is activated at step 765, the controller 100 determines at step 770 whether the wait time between current pulses is greater than or equal to a second wait time threshold (eg, fifteen seconds). If the waiting time is greater than or equal to the second waiting time threshold at step 770, the controller 100 changes the indicator 110 at step 775, for example, activates the second LED 120 so that the second LED 120 is displayed as a normally-on state. Module 225 then proceeds to the hold module of step 780 .

If the waiting time is not greater than or equal to the second waiting time threshold at step 770, the controller 100 determines whether the battery temperature is included in the range of -20 degrees Celsius to 0 degrees Celsius at step 785. If at step 785 the battery temperature is included within the range, then module 225 proceeds to step charging module 220 at step 790 . If at step 785 the battery temperature is not included within the range, module 225 will return to charge current algorithm 250 proceeding to step 740 .

FIG. 11 is a flowchart illustrating the retention module 230 . Operation of module 230 begins when main charging operation 200 enters hold module 230 at step 800 . The controller 100 determines whether the battery voltage is included in the range of 3.5V/cell to 4.05V/cell at step 805 . At step 805, if the battery voltage is not within range, the controller 100 continues at step 805 until the battery voltage is within range. Once the battery voltage is included within the range at step 805 , the controller 100 initializes a hold timer at step 810 . In some constructions, the hold timer counts down from thirty minutes.

In step 815, the controller 100 determines whether the battery temperature is in a range below -20 degrees Celsius or above 65 degrees Celsius. If the battery temperature is below -20 degrees Celsius or above 65 degrees Celsius, module 230 proceeds to the temperature out of range module 210 at step 820 and the module will stop at step 825 . If the battery temperature is not below -20 degrees Celsius or above 65 degrees Celsius at step 815 , module 230 proceeds to charging current algorithm 250 at module 830 .

Once the charge current algorithm 250 is executed at step 830 , the controller 100 determines at step 835 whether the hold timer has expired. If the hold timer has expired, module 230 proceeds to the bad group module of step 840 and module 230 will stop at step 845 . If the hold timer has not expired at step 835, the controller 100 determines at step 850 whether the wait time between current pulses is greater than or equal to a first predetermined hold wait time period, eg, fifteen seconds.

If at step 850 the wait time is greater than the first predetermined hold wait time period, module 230 proceeds to step 805 . If at step 850 the wait time is not greater than or equal to the first predetermined hold wait time period, module 230 proceeds to charge current algorithm 250 at step 830 . In some constructions, the current charger 30 will remain in the holding module 230 until the battery pack 20 is removed from the battery charger 30 .

FIG. 12 is a flowchart illustrating a basic charging scheme or charging current algorithm 250 . Operation of the module 250 begins when the other modules 220 - 230 or the main charging operation 200 enters the charging current algorithm at step 870 . The controller 100 applies a full current pulse at step 875 for approximately 1 second. At step 880 , the controller 100 determines whether the battery voltage 880 is greater than 4.6 V/cell when current is applied to the battery 20 .

If at step 880 the battery voltage is greater than 4.6V/cell, then the algorithm 250 will continue to the bad group module 205 at step 885 and the algorithm 250 will stop at step 890 . If the battery voltage is not greater than 4.6V/cell at step 880 , the controller 100 interrupts the charging current, increments a counter (such as a charging current counter), and stores the count value at step 895 .

In step 900, the controller 100 determines whether the battery temperature is in a range below -20 degrees Celsius or above 65 degrees Celsius. If the battery temperature is below -20 degrees Celsius or above 65 degrees Celsius at step 900 , the algorithm 250 proceeds to the temperature out of range module 205 at step 905 and the algorithm 250 will terminate at step 910 . If the battery temperature is not below -20 degrees Celsius or above 65 degrees Celsius at step 900 , then at step 915 the controller 100 will measure the battery voltage when charging current is not applied to the battery 20 .

In step 920, the controller 100 determines whether the battery voltage is less than 4.2V/cell. If at step 920 the battery voltage is less than 4.2 V/cell, the algorithm 250 proceeds to step 875 . If the battery voltage is not less than 4.2V/cell at step 920, the controller 100 waits at step 925 until the battery voltage is approximately equal to 4.2V/cell. And at step 925, the controller 100 stores the waiting time. The algorithm 250 stops at step 930 .

In another construction, the full charge current or full charge pulse applied by the battery charger 30 may be scaled based on the individual cell voltages in the battery 20 . This device will be described with reference to FIGS. 4 and 16 .

As shown in FIG. 4, the controller 100 in the battery charger 30 can receive information from the microcontroller 64 in the battery 20 and transmit information thereto. In some constructions, microcontroller 64 is capable of monitoring various battery characteristics during charging, either automatically or in response to commands from battery charger 30 , including the voltage or current state of charge of each battery cell 60 . The microprocessor 64 is capable of monitoring certain battery characteristics and processing and averaging the measurements during periods T _on of the charge current (that is, "current on" time periods). In some constructions, the current is conducted for a period of approximately one second ("1-s"). During periods of no charging current (ie, "current off" time periods) T _off , information related to certain battery characteristics (eg, cell voltage and cell state of charge) can be sent from battery 20 to charger 30 . In some constructions, the current off time period T _off is approximately 50 milliseconds. The battery charger 30 can thus process the information sent from the battery 20 and modify the current conduction time period T _on . For example, if one or more battery cells 60 have a higher current state of charge than the remaining battery cells 60, then battery charger 30 may taper the time to avoid overcharging one or more higher battery cells 60. Current over period T _on .

In some constructions, the battery charger 30 may compare each individual cell voltage to the average cell voltage, and if the difference between the individual cell voltages and the average cell voltage equals or exceeds a predetermined threshold (eg, non- balance threshold), the charger 30 may identify the unit as a unit with a higher state of charge. The battery charger 30 may vary the current during the time period T _on . In other constructions, battery charger 30 may estimate the state of charge for a particular battery cell (such as a battery cell identified as a higher voltage cell) based on information received from battery 20 during the current-on time period. In these constructions, if the estimate of the cell's current state of charge exceeds a threshold, then battery charger 30 may alter the duration of the current on-time period T _on .

For example, as shown in FIG. 16, the battery charger 30 can command the battery 20 to average the cell voltage measurements made at the next current-on time _Ton1 . This command can be sent during the first current off time period T _off1 . Thus, during the first current off time T _on1 , the microcontroller 64 measures and averages the cell voltage and other battery parameters. During the next current off time T _off2 the battery 20 can transmit the averaged measurement to the battery charger 30 . In some constructions, the battery 20 can transmit eight averaged measurements, eg, an averaged pack state-of-charge measurement and an averaged individual cell state-of-charge for each of the seven battery cells 60 . For example, battery 20 may send the following information: unit 1, 14%, unit 2, 14%, unit 3, 15%, unit 4, 14%, unit 5, 16%, unit 6, 14%, unit 7, 14 %, and pack voltage (eg, cells 1-7) voltage 29.96V. In this example, battery charger 30 identifies cell 5 as the upper cell. The charger 30 also records the battery voltage as measured by the battery microprocessor 64 and the battery charger 30 . In this example, the battery charger 30 measures the battery voltage as approximately 30.07V. The battery charger 30 calculates the difference in battery voltage measurements (eg, 110 mV) and determines that the voltage drop across the terminals and leads is approximately 110 mV.

During the subsequent on-time period T _on2 the battery charger 30 "estimates" the voltage of the cell 5 . For example, battery charger 30 samples measurements of the voltage of battery 20, and for each battery voltage measurement, estimates the state of charge of cell 5 according to the following equation:

(V _battery/ch -V _terminal )*V _unit/unit

where Vbattery _/ch is the voltage of the battery 20 as measured by the charger 30, _Vterminal is the voltage drop across the terminal (eg, 110 mV), and _Vunit is the cell voltage estimated as a percentage of the battery voltage. If the estimate of the voltage of the cell 5 exceeds the threshold, the battery charger 30 may alter the subsequent current-on time period T _on3 . As shown in FIG. 16 , the charger 30 identifies the cell 5 as a high cell, and modifies the subsequent current-on time period T _on3 to be about 800 mS. Therefore, the length T2 of the current on-time period T _on3 is smaller than the length T1 of the previous current on-time periods T _on1 and T _on2 .

In some constructions, the charger 30 continues to set subsequent current-on time periods (eg, T _on4-5 ) to approximately the length T2 (eg, 800 ms) of the previous current-on-time period T _on3 . If cell 5 (or another cell) continues to be identified as a high cell, charger 30 can then alter the subsequent current conduction time period (e.g., T _on6 ).

Fig. 13 schematically shows a further schematic view of the battery 20'. Battery 20' is similar to battery 20 and common elements are identified with the same reference numeral "'".

In some constructions, the circuit 62' includes an electrical component, such as an identification resistor 950, and the identification resistor 950 can have a set resistance. In other configurations, the electrical component may be a capacitor, inductor, transistor, semiconductor element, electrical circuit or another component that is resistive or capable of transmitting electrical signals, such as a microprocessor, digital logic component, or the like. In the illustrated construction, the resistance value of the identification resistor 950 can be selected based on the characteristics of the battery 20', such as the nominal voltage and the chemistry of the battery cells 60'. The inductive terminal 55' can be electrically connected to the identification electrode 950.

As shown schematically in Figure 13, the battery 20' can be electrically connected to an electrical device, such as a battery charger 960 (also shown schematically). Battery charger 960 can include a positive terminal 964 , a negative terminal 968 and a sense terminal 972 . Each terminal 964, 968, 972 of the battery charger 960 can be electrically connected to a corresponding terminal 45', 50', 55' (respectively) of a battery. The battery charger 960 also includes circuitry having electrical components such as a first resistor 976, a second resistor 980, solid state electronics or semiconductors 984, a comparator 988 and a processor, microcontroller or controller (not shown ). In some constructions, semiconductor 984 can include a transistor capable of operating in a saturated or “on” state and capable of operating in a cutoff or “off” state. In some constructions, comparator 988 may be a dedicated voltage monitoring device, microprocessor or processing unit. In other constructions, the comparator 988 may be included in the controller (not shown).

In some constructions, a controller (not shown) may be programmed to identify the resistance value of an electrical component within the battery 20', such as identifying resistor 958. The controller may also be programmed to determine one or more characteristics of the battery 20', such as the battery chemistry and nominal voltage of the battery 20'. As previously described, the resistance value of identification resistor 958 may correspond to a dedicated value associated with one or more specific battery characteristics. For example, the resistance value of identification resistor 958 may be included in a range of resistance values corresponding to the chemistry and nominal voltage of battery 20'.

In some constructions, the controller may be programmed to recognize the resistance range of the plurality of identification resistors 958 . In these configurations, each range corresponds to a battery chemistry, eg, NiCd, NiMH, Li-ion, etc. In some constructions, the controller may identify additional resistance ranges, each corresponding to another battery chemistry or another battery characteristic.

In some constructions, the controller can be programmed to recognize multiple voltage ranges. The voltages included in the voltage range may depend on or correspond to the resistance value of the identification resistor 958, such that the controller can determine the value of the resistor 958 based on the measured voltage.

In some constructions, the resistance value of the identification resistor 958 may further be selected to be unique for each possible nominal voltage value of the battery 20'. For example, within a range of resistance values, a first dedicated resistance value can correspond to a nominal voltage of 21V, a second dedicated resistance value can correspond to a nominal voltage of 16.8V, and a third dedicated resistance value can correspond to a nominal voltage of 12.6V. In some constructions, there may be more or fewer dedicated resistance values, each associated with a resistance range corresponding to a possible nominal voltage of another battery 20'.

In an exemplary implementation, battery 20 ′ is electrically connected to battery charger 960 . To identify the first battery characteristic, semiconductor 984 is switched to an "on" state under the control of additional circuitry (not shown). Identification resistor 958 and resistors 976 and 980 create a voltage divider network when semiconductor 984 is in the "on" state. The network establishes a voltage V _A at a first reference point 992 . If the resistance value of resistor 980 is much smaller than the resistance value of resistor 976 , then the voltage VA will be determined by the resistance values of identification resistor 958 and resistor 980 . In this implementation, voltage V _A is within a range determined by the resistance value of identification resistor 958 . The controller (not shown) measures voltage V _A at first reference point 992 and determines the resistance value of identification resistor 958 based on voltage V _A . In some constructions, the controller compares voltage V _A to multiple voltage ranges to determine battery characteristics.

In some constructions, the first battery characteristic to be identified may include battery chemistry. For example, any resistance value below 150k ohms may indicate that the battery 20' has a chemistry of NiCd or NiMH, and any resistance value of about 150k ohms or above may indicate that the battery 20' has a chemistry of Li or Li ions. Once the controller has determined and identified the chemistry of the battery 20', an appropriate charging algorithm or method will be selected. In other configurations, there are more each corresponding to a resistance range of another battery chemistry than the above example.

Continuing with the exemplary implementation, to identify the second battery characteristic, semiconductor 984 is switched to an "off" state under the control of additional circuitry (not shown). The identification resistor 958 and resistor 976 create a voltage divider network when the semiconductor 984 transitions to the "off" state. The voltage V _A of the first reference point 992 is now determined by the resistance values of the identification resistor 958 and the resistor 976 . The resistance value of the identification resistor 958 is selected such that, when the voltage V _BATT at the second reference point 880 is substantially equal to the nominal voltage of the battery 20', the voltage V _A at the first reference point 992 is substantially equal to that at the third reference point 992. Voltage V _REF at point 996 . If the voltage V _A at the first reference point 992 exceeds the fixed voltage V _OUT at the third reference point 996 , the output V _OUT of the comparator 988 changes state. In some configurations, the output V _OUT can be used to terminate charging or as an indicator to start additional functions, such as hold procedures, equalization procedures, discharge functions, additional charging schemes, etc. In some constructions, voltage V _REF may be a fixed reference voltage.

In some constructions, the identified second battery characteristic may include the nominal voltage of the battery 20'. For example, a general equation for calculating the resistance value for identification resistor 958 may be:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="100"\; label="R"\; filenames="H2003101180395E00041.png"\; state="\{\{state\}\}">R</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 100</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; REF</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 135</span>}}}{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; BATT</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; REF</span>}}}$

Where R ₁₀₀ is the resistance of identification resistor 958 , R ₁₃₅ is the resistance of resistor 976 , V _BATT is the nominal voltage of battery 20 ′, and V _REF is a fixed voltage, eg, about 2.5V. For example, within the range of resistance values for Li ion chemistries (mentioned earlier), a resistance value of about 150k ohms for identification resistor 958 can correspond to a nominal voltage of about 21V, and a resistance value of about 194k ohms can correspond to about A nominal voltage of 16.8V, and a resistance value of approximately 274.7k ohms can correspond to a nominal voltage of approximately 12.6V. In other constructions, more or fewer dedicated resistance values may correspond to additional or different battery pack nominal voltage values.

In the configuration shown, identification resistor 958 and third reference point 996 may be on the “high” side of current sense resistor 1000 . Placing identification resistor 958 and third reference point 996 in this manner reduces any relative voltage fluctuation between _VA and V _REF that occurs when charging current is present. If the identification resistor 958 and the third reference point 996 are positioned at ground 1004 and a charging current is applied to the battery 20', voltage fluctuations may occur at the voltage _VA .

In some constructions, battery charger 960 may also include charger control functionality. As previously discussed, the output V _OUT of the comparator 988 changes state when the voltage _VA is substantially equal to the voltage V _REF (indicating that the voltage V _BATT is equal to the nominal voltage of the battery 20 ′). In some constructions, when the output V _OUT of the comparator 988 changes state, charging current is no longer applied to the battery 20 ′. Once the charging current is interrupted, the battery voltage V _BATT begins to decrease. When the voltage V _BATT reaches the low threshold, the output V _OUT of the comparator 988 changes state again. In some constructions, the low threshold of voltage V _BATT is determined by the resistance value of hysteresis resistor 1008 . Once the output V _OUT of comparator 988 changes state again, the charging current is re-established. In some constructions, this loop repeats for a predetermined amount of time determined by the controller or for a specific amount of state changes made by the comparator 988 . In some constructions, this cycle repeats until the battery 20 ′ is removed from the battery charger 30 .

In some constructions and some aspects, a battery, such as battery 20 as shown in FIG. As shown in Figure 17, the battery 20 may include one or more battery cells 60, a positive terminal 1105, a negative terminal 1110 and one or more sensing terminals 1120a and 1120b (as shown in Figure 17, a second sensing terminal or activation terminal 120b may or may not be included in battery 20). The battery 20 may also include a circuit 1130 including a microcontroller 1140 .

As shown in FIG. 17, circuit 130 may include a semiconductor switch that interrupts the discharge current when circuit 1130 (e.g., microprocessor 1140) determines or senses a charge above or below a predetermined threshold (i.e., an "abnormal battery condition"). 1180. In some constructions, the switch 1180 includes an interrupt condition in which current flow from or to the battery 20 is interrupted, and an enable condition in which current flow from or to the battery 20 is permitted. In some constructions, may include abnormal battery conditions such as high or low cell temperature, high or low battery state of charge, high or low cell state of charge, high or low discharge current, high or low charge current and so on. In the illustrated configuration, switch 1180 comprises a power FET or a metal oxide semiconductor FET ("MOSFET"). In other configurations, the circuit 1130 may include two switches 1180 . In these configurations, switches 1180 may be arranged in parallel. Parallel switches 1180 may be included in battery packs that employ high average discharge currents (eg, batteries 20 that power circular saws, power drills, etc.).

In some constructions, once the switch 1180 becomes non-conductive, the switch 1180 may reset even if the abnormal condition is no longer detected. In some constructions, circuitry 1130 (eg, microprocessor 1140) may only reset switch 180 if an electrical device, eg, battery charger 30, instructs microprocessor 1140 to do so. As previously mentioned, the battery 20 may be so over-discharged that the battery cells 60 may not have sufficient voltage to power the microprocessor 1140 to communicate with the battery charger 30 .

In some configurations, if the battery 20 cannot communicate with the charger 30 , the battery charger 30 provides a small charging current through the body diode 1210 of the switch 1180 to slowly charge the battery cell 60 . Microprocessor 1140 may change the state of switch 1180 once unit 60 has received sufficient charging current to power microprocessor 1140 . That is, the battery 50 can be charged even when the switch 1180 is in a non-conductive state. As shown in FIG. 17, switch 180 may include a body diode 1210, which in some configurations is integral to MOSFETs and other transistors. In other configurations, diode 1210 can be electrically connected in parallel with switch 1180 .

In some constructions, if the battery 20 is unable to communicate with the charger 30, the battery charger 30 may apply a small average current through sense leads, eg, sense lead 120a and dedicated enable terminal 120b. This current may charge capacitor 1150, which in turn may provide sufficient voltage to microprocessor 1140 to initiate operation.

The structures described and illustrated above are presented in an exemplary manner, and are not intended to limit the concepts and principles of the present invention. Likewise, it will be apparent to those skilled in the art that various changes can be made in the elements and in their arrangement and arrangement without departing from the spirit and scope of the invention.

Claims (49)

1. An electrical combination comprising: A first battery having a lithium-based chemistry, the first battery having a first nominal voltage within a nominal voltage range, the first battery including an identification element indicating said first battery of the first battery one of nominal voltage and nominal voltage range; A second battery having a lithium-based chemistry, the second battery having a second nominal voltage within a nominal voltage range, the second nominal voltage being different from said first nominal voltage, and within the first Outside the nominal voltage range of the battery, the second battery includes an identification element indicating one of said second nominal voltage and nominal voltage range of the second battery; and a battery charger operable to identify one of the nominal voltage and nominal voltage range of the first battery and the nominal voltage and nominal voltage range of the second battery, and to use the lithium-based battery The charging operation method is used to charge the first battery and the second battery. 2. The electrical combination of claim 1, wherein the first battery includes an identification element having a value representing one of a first nominal voltage and a nominal voltage range, and wherein the charger is operable to identify the Identifies the value of the component. 3. The electrical combination of claim 2, wherein the first battery includes a battery controller, and wherein the identification element includes the battery controller. 4. The electrical combination of claim 2, wherein the first battery includes a chemical identification element having a value indicative of the lithium-based chemistry of the first battery. 5. The electrical combination of claim 4, wherein the first battery includes a battery controller, and wherein the chemical identification element includes the battery controller. 6. The electrical combination of claim 4, wherein the charger includes a controller operable to recognize the value of the chemical identification element. 7. The electrical combination of claim 2, wherein the charger includes a controller operable to recognize the value of the identification element. 8. An electrical combination as claimed in claim 7, wherein the controller is operable to control the supply of charging current to charge the battery. 9. The electrical combination of claim 7, wherein the controller is operable to monitor battery characteristics including at least one of: battery nominal voltage, battery cell nominal voltage, battery current state of charge , battery cell current state of charge, battery temperature, battery cell temperature, number of battery cells, and battery chemistry. 10. The electrical combination of claim 9, wherein the controller is operable to control charging of the first and second batteries. 11. The electrical combination of claim 10, wherein the charging includes one of termination of charging of the first battery and termination of a charging mode charging the first battery. 12. The electrical combination of claim 10, wherein the charging includes one of initialization of charging of the first battery and initialization of a charging mode for charging the first battery. 13. The electrical combination of claim 10, wherein the controller selects a threshold for charging when the controller identifies the value of the identification element. 14. The electrical combination of claim 13, wherein the threshold comprises a first battery voltage threshold. 15. The electrical combination of claim 13, wherein the first battery voltage threshold is associated with one of a first nominal voltage and a nominal voltage range. 16. The electrical combination of claim 13, wherein said second nominal voltage is within a second nominal voltage range that is different from said first nominal voltage range. 17. The electrical combination of claim 16, wherein said second battery includes a second identification element having a second value indicative of one of a second nominal voltage and a second nominal voltage range, wherein said charging The controller is operable to identify a second value of the second identification element, when the controller identifies the second value of the second identification element, the controller selects a second threshold for charging, the second threshold being different from the threshold. 18. The electrical combination of claim 17, wherein the charging includes one of termination of charging of the second battery and termination of a charging mode charging the second battery. 19. The electrical combination of claim 17, wherein the charging includes one of initiation of charging of the second battery and initiation of a charging mode for charging the second battery. 20. The electrical combination of claim 17, wherein said threshold comprises a first battery voltage threshold, and wherein said second threshold comprises a second battery voltage threshold different from said first battery voltage threshold. battery voltage threshold. 21. The electrical combination of claim 20, wherein the second battery voltage threshold is associated with one of a second nominal voltage and a second nominal voltage range. 22. The electrical combination of claim 1, wherein said second nominal voltage is within a second nominal voltage range, said second nominal voltage range being different from said first nominal voltage range. 23. The electrical combination of claim 22, wherein the second battery includes an identification element having a value indicative of one of a second nominal voltage and a second nominal voltage range, and wherein the charger is operable to identify the value of the identified element. 24. The electrical combination of claim 23, wherein the second battery includes a battery controller, wherein the identification element includes the battery controller. 25. The electrical combination of claim 23, wherein the second battery includes a chemical identification element having a value indicative of the lithium-based chemistry of the first battery. 26. The electrical combination of claim 25, wherein the second battery includes a battery controller, and wherein the chemical identification element includes the battery controller. 27. The electrical combination of claim 25, wherein the charger includes a controller operable to recognize the value of the chemical identification element. 28. A method of charging a battery using a battery charger, a first battery having a lithium based chemistry, said first battery having a first nominal voltage within a first nominal voltage range, a second battery having a lithium based chemistry Lithium chemistry, the second battery having a second nominal voltage within a second nominal voltage range, the second nominal voltage being different from the first nominal voltage, the second nominal voltage range different from said first nominal voltage range, the battery charger is operable to charge a first battery and a second battery, said method comprising the following actions: electrically connecting the battery charger and the first battery; receiving a signal from the first battery indicative of one of a nominal voltage and a nominal voltage range of the first battery; identifying one of a nominal voltage and a nominal voltage range of the first battery; charging the first battery via constant current pulse charging based on one of a nominal voltage and a nominal voltage range of the first battery; electrically connecting the battery charger and the second battery; receiving a signal from the second battery indicative of one of a nominal voltage and a nominal voltage range of the second battery; identifying one of a nominal voltage and a nominal voltage range of the second battery; and The second battery is charged via constant current pulse charging based on one of a nominal voltage and a nominal voltage range of the second battery. 29. The method of claim 28, and further comprising the act of identifying the chemistry of one of the first battery and the second battery. 30. The method of claim 28, and further comprising the act of receiving a signal from the battery, the signal indicative of a chemistry of one of the first battery and the second battery. 31. The method of claim 28, and further comprising the act of monitoring battery characteristics including at least one of: battery nominal voltage, battery cell nominal voltage, battery current state of charge, battery cell current State of charge, battery temperature, battery cell temperature, number of battery cells, and battery chemistry. 32. The method of claim 28, wherein the controlling action comprises an action of controlling termination of charging of one of the first battery and the second battery and termination of a charging mode for charging one of the first battery and the second battery one of the actions. 33. A method as claimed in claim 28, wherein said controlling action comprises an action of controlling initial charging of one of the first battery and the second battery and initializing a charging mode for charging the one of the first battery and the second battery one of the actions. 34. The method of claim 28, and further comprising the act of selecting a threshold for charging based on one of a nominal voltage and a nominal voltage range of one of the first battery and the second battery. 35. The method of claim 34, and further comprising the act of selecting the threshold for charging based on one of the first nominal voltage and the first nominal voltage range of the first battery. 36. The method of claim 35, and further comprising the act of selecting a second threshold for charging based on one of a second nominal voltage and a second nominal voltage range of the second battery, the second threshold being different at the threshold. 37. A battery having a lithium-based chemistry, the battery having a nominal voltage within a nominal voltage range, the battery comprising: a plurality of battery cells each having a lithium-based chemistry; a chemical identification element that represents the chemistry of the plurality of battery cells; and an identification element representing one of the nominal voltage and the nominal voltage range of the battery; wherein said battery is operable with an electrical device, the electrical device being one of a power tool and a battery charger, capable of transferring electrical power between the battery and the electrical device, the electrical device using said identification element and said chemical substance An identification element identifies one of a nominal voltage and a nominal voltage range of the battery and a chemistry of the battery. 38. The battery of claim 37, wherein the battery includes a controller, and wherein the chemical identification assembly includes the controller. 39. The battery of claim 37, wherein the battery includes a controller, wherein the identification element includes the controller. 40. The battery of claim 37, wherein said electrical device comprises a battery charger operable to supply a charging current to the battery to charge the battery, the chemistry of the battery and the nominal voltage and nominal voltage range of the battery One of them can be identified by the battery charger. 41. An electrical combination comprising: A first battery having a first plurality of battery cells, each cell in the first set having a lithium-based chemistry, the first battery including an identification element indicative of the lithium-based chemistry of the first battery substance; a second battery having a second plurality of battery cells, each cell in the second set having one of a nickel-cadmium chemistry and a nickel-metal hydride chemistry; and a battery charger operable to charge the first battery and the second battery via constant current pulse charging, the battery charger including a controller operable to identify the lithium-based chemistry of the first battery; Wherein the battery charger receives a signal indicative of a lithium-based chemistry of the first battery. 42. The electrical combination of claim 41, further comprising a third battery having a chemistry other than nickel cadmium and nickel metal hydride, and wherein said battery charger is operable to charge the third battery. 43. The electrical combination of claim 41, wherein the battery charger is operable to recognize the lithium-based chemistry of the first battery. 44. The electrical combination of claim 41, wherein the battery charger includes a charging circuit connectable to a power source and operable to provide charging current to the first battery and the second battery. 45. The electrical combination of claim 44, wherein the battery charger includes a controller operable to control the charging circuit and to control the supply of charging current to the first battery and the second battery through the charging circuit. 46. The electrical combination of claim 45, wherein the controller is operable to identify the lithium-based chemistry of the first battery and control the charging circuit to control the charging current provided to the first battery by the charging circuit. 47. The electrical combination of claim 45, wherein the controller is operable to control the charging circuit to provide charging current to the first battery via a first charging algorithm, and to provide charging current to the second battery via a second charging algorithm. For batteries, the first charging algorithm is different from the second charging algorithm. 48. The electrical combination of claim 41, wherein said first battery has a first nominal voltage within a first nominal voltage range, wherein said electrical combination further comprises a battery having a nominal voltage within a nominal voltage range. voltage of a third battery, the third battery has a nominal voltage different from the first nominal voltage, the third battery has a nominal voltage range different from the first nominal voltage range, and wherein the battery charger is operable with to charge the third battery. 49. The electrical combination of claim 48, wherein the battery charger is operable to identify one of a nominal voltage and a nominal voltage range of the first battery and the third battery.

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