DE10354874B4 - Battery charger - Google Patents

Abstract

A battery charger (30) operable to charge a first battery (20) and a second battery (20), the battery charger comprising:a controller (100); and a charging circuit (95) operable to charge the first and second batteries, the first battery (20) comprising a first plurality of battery cells (60), each cell in the first plurality having a lithium-based chemistry, and wherein the first battery has a first rated voltage in a rated voltage range, and wherein the second battery has a second plurality of battery cells, each cell in the second plurality having a lithium-based chemistry, and wherein the second battery has a second rated voltage, the second rated voltage being different from the first nominal voltage and is outside the nominal voltage range, the total number of cells in the first plurality being different from the total number of cells in the second plurality, the controller being operable to operate from the first battery coupled to the battery charger, Receive information regarding an individual state of charge of at least one of the first plurality of battery cells, the controller being operable to control the battery charging device to supply the first battery coupled to the battery charging device with a charging current that is at least partially based on the individual state of charge of the at least one of the first plurality of battery cells, and to control the charging current by controlling the battery charging device so that the charging current is delivered in a plurality of pulses, the plurality of pulses each having a first time period during which the charging current of the battery coupled to the battery charging device is supplied at a predefined amplitude, and has a second time period during which the supply of charging current is interrupted, and to control the charging current by modifying the first period of time and by controlling the second period of time to a constant size.

Description

FIELD OF THE INVENTION

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

Cordless power tools are typically powered by portable battery packs. These battery packs vary in battery type and voltage rating and can be used to power many tools and electrical devices. Typically, a power tool battery is made of either nickel-cadmium (“NiCd”) or nickel-metal hydride (“NiMH”). The nominal voltage of the battery pack usually ranges from about 2.4V to about 24V.

The US 6,362,596 B1 discloses a method for charging a rechargeable battery pack, in which the battery capacity is determined and the charging power is set accordingly based on the battery capacity. Furthermore, this publication discloses that a battery charger has a charging device for different battery types and can distinguish between the two battery types based on a battery identification signal. The battery packs according to this publication are used for power tools or kitchen and household appliances. The rechargeable batteries are based on lithium, nickel, cadmium and lead and via the IDIN input connection the controller can determine the type and capacity of the battery to be charged.

The US 6,124,698 A refers to a battery charger capable of charging either a battery pack containing a nickel metal hydride battery or a battery pack containing a nickel cadmium battery, such as those used for power drills. The battery charger can detect whether a connected battery pack is a nickel metal hydride or nickel cadmium battery pack by evaluating a different position of two input terminals. Based on this different position of the connections, the battery type is determined.

The US 5,656,917 A refers to a battery identification system and a charger for charging the respective battery. This battery identification is addressed in the context of a charging system for a mobile phone. In addition, the complete battery identification is carried out using the electronic device disclosed here, but without direct communication between the charger and the battery.

The US 6,222,343 B1 discloses a battery charger that is capable of charging various types of batteries and can also work with various AC voltage sources. According to this document, a thermistor sensor circuit is provided to determine the type of battery and also to determine whether it is a nickel cadmium or a nickel metal hydride battery.

The US 5,963,010 A finally refers to a battery control for controlling the charging of at least two batteries of different types. The control has a detection unit for detecting the type of battery and is therefore able to charge and discharge different types of batteries. For example, as stated in column 10, lines 44 to 53, charging and discharging are performed according to the battery type detection signal, and the battery detected by this device may be any type of battery having a thermistor terminal.

From the DE 195 04 437 A1 A universal battery charger is known in which, in order to charge a battery that has a different number of cells connected in series with a corresponding charging current, the number of cells in the battery is first determined. A current level is set according to the number of cells taking into account the capacity of the charger. A charging current flows in the battery, the level of which is essentially equal to the current level determined in this way.

The US 5,684,387 A discloses a battery charging system capable of maintaining a fully charged battery without overcharging or undercharging the battery, regardless of chemical type, number of cells, state of charge, or rated charging current. A charging technology allows a charger to measure a capacity indicator of the battery via a capacity resistor or memory, located in the battery and converting data relating to the number of battery cells, battery chemistry and rated charging current into a relative impedance, a turn-off adjustment voltage and a steady-state turn-off voltage.

The US 5,153,496 A discloses a cell monitoring and control circuit for a multi-cell battery comprising a cell access switch coupled to the cells of the battery for electronic access to individual cells of the battery and a monitoring and control circuit coupled to the cell access switch for electronic communication with the cells. The circuit is connected to the battery to supply power to it and represents insignificant power consumption for the battery. The circuit senses the voltage state of each cell and controls the charging process of each cell and provides signals for the end of discharge and the end of the charging process.

Some battery types (such as lithium (“Li”), lithium-ion (“Li-ion”) and other lithium-based chemistries) require precise charging schemes and controlled discharge charging operations. Insufficient charging schemes and uncontrolled discharging schemes can produce excessive heat generation, excessive overcharged conditions and/or excessively discharged conditions. These conditions and generation can cause irreversible damage to batteries and can severely impact battery capacity.

The present invention provides a system and method for charging a battery. In some constructions and some aspects, the invention provides a battery charger that can fully charge various battery packs with batteries of different chemical makeup. In some constructions and in some aspects, the invention provides a battery charging device capable of charging lithium-based batteries, such as lithium-cobalt batteries, lithium-manganese batteries, and spinel batteries. In some constructions and in some aspects, the invention provides a battery charger that can charge lithium-based battery packs of different voltage ratings or in different voltage ranges. In some constructions and in some aspects, the invention provides a battery charging device having various charging modules implemented based on different battery conditions. In some constructions and in some aspects, the invention provides a method and system for charging a lithium-based battery by applying constant current pulses. The time between the pulses and the length of the pulses can be increased or decreased by the battery charging device depending on certain battery properties.

Independent features and independent advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

• 1 is a perspective view of a battery.
• 2 is another perspective view of a battery, like the battery shown in 1 is shown.
• 3 is a perspective view of a battery, like the battery shown in 1 is shown, which is electrically and physically connected to a battery charging device.
• 4 is a schematic view of a battery electrically connected to a battery charger, such as the battery and battery charger described in 3 are shown.
• 5a and 5b are flowcharts showing the operation of a battery charger embodying aspects of the invention, such as the battery charger described in 3 is shown.
• 6 is a flowchart showing a first module that may be implemented on a battery charger embodying aspects of the invention, such as the battery charger described in 3 is shown.
• 7 is a flowchart showing a second module mounted on a battery charger embodying aspects of the present invention, such as the battery charger described in 3 shown can be implemented.
• 8th is a flowchart showing a third module mounted on a battery charger embodying aspects of the present invention, such as the battery charger described in 3 shown can be implemented.
• 9 is a flowchart showing a fourth module mounted on a battery charger embodying aspects of the present invention, such as the battery charger described in 3 shown can be implemented.
• 10 is a flowchart showing a fifth module mounted on a battery charger embodying aspects of the present invention, such as the battery charger described in 3 shown can be implemented.
• 11 is a flowchart showing a sixth module mounted on a battery charger embodying aspects of the present invention, such as the battery charger described in 3 shown can be implemented.
• 12 is a flowchart showing a charging algorithm applied to a battery charging device embodying aspects of the invention, such as the battery charging device described in 3 shown can be embodied.
• 13 is a schematic diagram of a battery electrically connected to a battery charger.
• 14A and 14B are views of other constructions of a battery.
• 15A and 15B are perspective views of a battery, like one of the batteries found in the 1 , 2 and 14A and 14B are shown, which is electrically and physically connected to a power tool.
• 16 is a schematic view of the charging current for a battery.
• 17 is another schematic diagram of a battery.

Before any embodiments of the invention are explained in detail, it should be understood that the invention is not limited in its application to the details of construction and arrangement of components set forth in the following description or shown in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. It should also be understood that the language and terminology used herein is intended to be descriptive and not limiting. The use of "include", "comprise" or "have" and variations thereof are intended to include the items listed below and equivalents thereof as well as additional items.

DETAILED DESCRIPTION OF DRAWINGS

A battery pack or battery 20 is in the 1 and 2 shown. The battery 20 is configured to provide power to one or more electrical devices, such as a power tool 25 (shown in FIGS 15A and 15B is shown) and/or a battery charger 30 (which is shown in FIGS 3 and 4 shown) to deliver or receive from there. In some constructions and in some aspects, the battery 20 may have a chemical makeup such as lead-acid, nickel-cadmium (“NiCd”), nickel-metal hydride (“NiMH”), lithium (“Li”), lithium -ions (“L-ions”) and other lithium-based chemical compositions or other rechargeable batteries with a different chemical composition. In some constructions and in some aspects, the battery 20 can deliver a high discharge current to electrical devices, such as a power tool, having high current discharge rates. In the illustrated constructions, the battery 20 has a chemical composition of Li, Li-ion, or other lithium-based chemical composition and provides an average discharge current that is equal to or greater than about 20 A. For example, in the illustrated construction, the battery 20 may have a chemical composition of lithium-cobalt (“Li-Co”), lithium-manganese (“Li-Mn”) spinel, or Li-Mn-nickel.

In some constructions and some aspects, the battery 20 may also have any voltage rating, such as a voltage rating ranging from about 9.6 V to about 50 V. In a construction (see 1 until 3 ), for example, the battery 20 has a nominal voltage of approximately 21 V. In another construction (see 14 ), the battery 20A has a nominal voltage of approximately 28 volts. It should be understood that in other designs, the battery 20 may have a different voltage rating in a different voltage rating range.

The battery 20 includes a housing 35 that provides connection carriers 40. The battery 20 further includes one or more battery terminals which are carried by the terminal carriers 40 and which are connectable to an electrical device, such as a power tool 25 and/or a battery charging device 30. In some constructions, such as the construction in 4 As shown, the battery 20 includes a positive battery terminal 45, a negative battery terminal 50, and a measurement battery terminal 55. In some constructions, the battery 20 includes more or fewer terminals than in the construction shown above.

The battery 20 includes one or more battery cells 60, each having a chemical structure and a rated voltage. In some constructions, the battery 20 includes a Li-ion chemical battery structure, a voltage rating of approximately 18V or 21V, and five battery cells. In some constructions, each battery cell 60 has a Li-ion chemical makeup, and each battery cell 60 has substantially the same voltage rating, such as about 3.6 V or about 4.2 V.

In some constructions and in some aspects, the battery 20 includes an identification circuit or component electrically connected to one or more battery terminals. In some constructions, an electrical device such as a battery charger 30 (shown in Figs 3 and 4 shown) “read” the identification circuit or component or receive input based on the identification circuit or component to determine one or more battery characteristics. In some designs, the battery characteristics would include, for example, the voltage rating of the battery 20, the temperature of the battery 20, and/or the chemical makeup of the battery 20.

In some constructions and in some aspects, the battery 20 includes a controller, microcontroller, microprocessor, or controller electrically connected to one or more battery terminals. The controller communicates with the electrical devices, such as the battery charger 30, and provides information to the devices regarding one or more battery characteristics or conditions, such as the nominal voltage of the battery 20, the individual cell voltages, the temperature of the battery 20, and/or the chemical structure of the battery 20. In some structures, such as the structure in 4 As shown, the battery 20 includes an identification circuit 62 having a microprocessor or controller 64.

In some constructions and in some aspects, the battery 20 includes a temperature measuring device or a thermistor. The thermistor is configured and positioned within the battery 20 to measure a temperature of one or more battery cells or a temperature of the battery 20 as a whole. In some constructions, such as the construction in 4 As shown, battery 20 includes a thermistor 66. In the illustrated construction, thermistor 66 is included in identification circuit 62.

Like in the 3 and 4 As shown, the battery 20 is also configured to connect to an electrical device, such as a battery charger 30. In some constructions, the battery charger 30 includes a housing 70. The housing 70 provides a connector portion 75 to which the battery 20 is connected. The connecting part 75 includes one or more electrical device terminals to electrically connect the battery 20 to the battery charging device 30. The terminals included in the battery charger 30 are configured to mate with the terminals included in the battery 20 and to transmit and receive power and information from the battery 20.

In some constructions, such as the construction in 4 As shown, the battery charger 30 includes a positive terminal 80, a negative terminal 85, and a measurement terminal 90. In some constructions, the positive terminal 80 of the battery charger 30 is configured to mate with the positive battery terminal 45. In some constructions, the negative terminal 85 and the measuring terminal 90 of the battery charger 30 are configured to mate with the negative battery terminal 50 and the battery measuring terminal 55.

In some constructions and in some aspects, the battery charger 30 also includes a charging circuit 95. In some constructions, the charging circuit 95 includes a controller, microcontroller, microprocessor, or controller 100. The controller 100 controls the transfer of power between the battery 20 and the Battery charger 30. In some designs, the controls Controller 100 transfers information between the battery 20 and the battery charger 30. In some constructions, the controller 100 identifies and/or determines one or more characteristics or states of the battery 20 based on signals received from the battery 20. The controller 100 may also control the operation of the charging device 30 based on the identification characteristics of the battery 20.

In some constructions and in some aspects, the controller 100 includes various timers, backup timers, and counters and/or may perform various timing and counting functions. The timers, backup timers, and counters are used and controlled by the controller 100 during various loading steps and/or modules. The timers, backup timers and controls are discussed below.

In some constructions and in some aspects, the battery charger 30 includes a display or indicator 110. The indicator 110 informs a user of the status of the battery charger 30. In some constructions, the indicator 110 may inform the user of various stages of charging, charging modes, or charging modules how they are started and/or ended during operation. In some constructions, the indicator 110 includes a first light-emitting diode 115 (“LED”) and a second LED 120. In the illustrated construction, the first and second LEDs 115 and 120 are differently colored LEDs. 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 the indicator 110. In some constructions, the indicator 110 is disposed on the housing 70 or in the housing 70 so that the indicator 110 is visible to the user. The display could also include an indicator showing the percentage of charge, remaining time, etc. In some constructions, the display or indicator 110 may include the charge indicator provided on the battery 20.

The battery charger 30 is adapted to receive an input of energy from a power source 130. In some constructions, the power source 130 is an alternating voltage signal of approximately 120 volts at 60 Hz. In other constructions, the power source 130 is, for example, a constant current source.

In some constructions and in some aspects, the battery charger 30 may charge various rechargeable batteries having different battery chemistries and different voltage ratings, as described below. For example, in an exemplary implementation, the battery charger 30 may charge a first battery having a NiCd chemical battery structure and a voltage rating of approximately 14.4 volts, a second battery having a Li-ion battery chemical structure and a voltage rating of approximately 18 volts, and a third battery having a Li-ion chemical battery structure and a voltage rating of approximately 28 volts. In another example implementation, the battery charger 30 may charge a first Li-ion battery having a nominal voltage of approximately 21 V and a second Li-ion battery having a nominal voltage of approximately 28 V. In this exemplary implementation, the battery charger 30 may identify the nominal voltages of each battery 20 and either scale certain thresholds accordingly, as discussed below, or modify the voltage readings or measurements (obtained during charging) according to the battery's nominal voltage.

In some constructions, the battery charger 30 may identify the voltage rating of a battery 20 by “reading” an identification component included in the battery 20 or by receiving a signal from, for example, a battery microprocessor or controller. In some constructions, the battery charger 30 may include a range of acceptable voltage ratings for different batteries 20 that the charger 30 can identify. In some designs, the range of acceptable voltage ratings may include a range from about 8 volts to about 50 volts. In other designs, the range of acceptable voltage ratings may include a range from about 12V to about 28V. In further designs, the battery charger 30 can identify nominal voltages that are approximately 12V and above. In further constructions, the battery charger 30 may identify nominal voltages of approximately 30 volts or lower.

In other constructions, the battery charger 30 may identify a range of values that include the rated voltage of the battery 20. For example, instead of identifying that a first battery 20 has a nominal voltage of approximately 18 V, the battery charger 30 may have a Perform identification that the rated voltage of the first battery 20 falls in the range of, for example, about 18 volts to about 22 volts or about 16 volts to about 24 volts. In further constructions, the battery charger 30 may also identify other battery characteristics, such as the number of battery cells, the chemical composition of the battery, and the like.

In other constructions, the charger 30 may identify any voltage rating of the battery 20. In these designs, the charging device 30 can charge the battery 20 at any rated voltage by setting or scaling certain thresholds according to the rated voltage of the battery 20. Each battery 20 in these designs can also receive approximately the same amplitude of charging current for approximately the same amount of time regardless of rated voltage (e.g., when each battery 20 is approximately fully charged). The battery charger 30 may either adjust or scale the thresholds (as discussed below) or adjust or scale the measurements according to the rated voltage of the battery 20 being charged.

For example, the battery charger 30 may identify a first battery having a voltage rating of approximately 21 volts and 5 battery cells. During charging, the battery charger 30 modifies each measurement that the charger 30 samples (e.g., battery voltage) to obtain one measurement per cell. That is, the charger 30 divides each measurement of battery voltage by 5 (for example, five cells) to obtain approximately the average voltage of a cell. Thus, all threshold values included in the battery charger 30 may correspond to one measurement per cell. The battery charger 30 may also identify a second battery having a voltage rating of approximately 28 volts and 7 battery cells. Similar to operation with the first battery, the battery charger 30 modifies each voltage measurement to obtain one measurement per cell. Again, all threshold values included in the battery charger 30 may correspond to one measurement per cell. In this example, the battery charger 30 may use the same monitoring and termination thresholds for the first and second batteries to allow the battery charger 30 to charge many batteries in a range of nominal voltages.

In some constructions and in some aspects, the battery charger bases the charging scheme or method for charging the battery 20 on the temperature of the battery 20. In one construction, the battery charger 30 delivers a charging current to the battery 20 while periodically controlling the temperature of the battery 20 detected or monitored. If the battery 20 does not include a microprocessor or controller, the battery charger 30 periodically measures the resistance of the thermistor 66 after predefined periods of time. If the battery 20 includes a microprocessor or a controller, such as the controller 64, then (1) the battery charger 30 either periodically polls the controller 64 to determine the battery temperature and/or whether the battery temperature is outside an appropriate operating range, or (2) wait to receive a signal from controller 64 indicating that the battery temperature is not within an appropriate operating range, as discussed below.

In some constructions and in some aspects, the battery charger 30 bases the charging scheme or method for charging the battery 20 on the current voltage of the battery 20. In some constructions, the battery charger 30 supplies a charging current to the battery 20 while periodically increasing the battery voltage detected or monitored at predetermined time periods when power is being delivered to the battery 20 and/or when power is not being delivered, as discussed below. In some constructions, the battery charger 30 bases the charging schedule or method for charging the battery 20 on both the temperature and the voltage of the battery 20. The charging schedule may also be based on the voltages of individual cells.

If the battery temperature and/or the battery voltage exceeds a predefined threshold or does not fall within an appropriate operating range, the battery charging device 30 interrupts the charging current. The battery charger 30 further periodically detects or monitors the battery temperature/voltages or waits to receive a signal from the controller 64 indicating that the battery temperature/voltages are within an appropriate operating range. When the battery temperature/voltages are within an appropriate operating range, the battery charger 30 can resume the charging current supplied to the battery 20. The battery charger 30 further monitors the battery temperature/voltages and interrupts and resumes the charging current based on the detected battery temperature/voltages. In some constructions, the battery charger 30 stops charging after a predetermined period of time or when the battery capacity reaches a predefined threshold. In other constructions, charging is terminated when the battery 20 is removed from the battery charger 30.

In some constructions and in some aspects, the battery charging device 30 includes a method of operation for charging various batteries, such as battery 20, that have different chemical compositions and/or voltage ratings. An example of this charging operation 200 is in the 5a and 5b shown. In some constructions and in some aspects, the battery charging device 30 includes a method of operation for charging Li-based batteries, such as batteries having a Li-Co chemical composition, a Li-MN chemical composition, a Li-Mn-Nickel chemical composition and the like. In some constructions and in some aspects, the charging operation includes 200 different modules for performing different functions in response to different battery conditions and/or battery characteristics.

In some constructions and in some aspects, the method of operation includes 200 modules for interrupting charging based on abnormal and/or normal battery conditions. In some constructions, the load operation 200 includes a defect set module, such as the defect set module shown in flowchart 205 of the 6 is shown, and/or a temperature-out-of-range module, such as the temperature-out-of-range module shown in flowchart 210 of the 7 is shown. In some constructions, the battery charger 30 enters the defect set module 205 to terminate charging based on an abnormal battery voltage, an abnormal cell voltage, and/or an abnormal battery capacity. In some constructions, the battery charger 30 enters the temperature-out-of-range module 210 to terminate charging based on abnormal battery temperature and/or abnormal battery cell temperatures. In some designs, the charging operation includes 200 more or fewer modules that complete charging based on more or fewer battery states than the modules and states discussed above and below.

In some constructions and in some aspects, the charging operation 200 includes different modes or modules for charging the battery 20 based on various battery conditions. In some constructions, the charging operation 200 includes a trickle charging module, such as the trickle charging module shown in flowchart 215 of the 8th is shown, a step load module, such as the step load module shown in flowchart 220 of 9 is shown, a fast charging module, such as the fast charging module shown in flowchart 225 of 10 is shown, and/or a maintenance load module, such as the maintenance load module shown in flowchart 230 of 11 is shown.

In some constructions and in some aspects, each charging module 215 to 230 is selected by the controller 100 during charging operation 200 based on certain ranges of battery temperature, certain ranges of battery voltage, and/or certain ranges of battery capacities. In some constructions, each module 215 to 230 is selected by the controller 100 based on the battery characteristics shown in Table 1. In some designs, the state “battery temperature” or “temperature of the battery” may include the temperature of the battery as a whole (i.e. the battery cells, the battery components, etc.) and/or the temperature of the battery cells taken individually or collectively. In some constructions, each charging module 215 to 230 may be based on the same basic charging scheme or charging algorithm, such as full charging current, as discussed below.

Operation for charging Li-based batteries Table 1 Battery voltage (V/cell) Battery temperature (°C) < _T1 T ₁ to T _{2 T2} to _T3 > _T3 < _V1 No charging, slow flashing of the first LED Trickle charge first LED constantly on Trickle charge first LED constantly on No charging, slow flashing of the first LED _V1 to _V2 No charging, slow flashing of the first LED Step charge first LED steadily on until near full charge, then off. Second LED flashes near full charge Fast charge first LED steadily on until near full charge, then off. Second LED flashes near full charge No charging, slow flashing of the first LED _V2 to _V3 No charging, slow flashing of the first LED Maintenance charging Second LED constantly on Maintenance charge second LED lights up steadily No charging, slow flashing of the first LED > _V3 No charging, first LED flashes quickly No charging. First LED flashes quickly No charging. First LED flashes quickly No charging, first LED flashes quickly

In some constructions and in some aspects, the charging current applied to the battery 20 during the trickle charge module 215 includes applying a full charging current (e.g., “I”) to the battery 20 for a first period of time, such as 10 seconds, and then canceling the full charging current for a second period of time, for example fifty seconds. In some designs, the full charging current is a pulse of charging current with an approximately predefined amplitude. In some constructions, the battery charger 30 enters the trickle charge module 215 only when the battery voltage is less than a first predefined voltage threshold V ₁ .

In some constructions and in some aspects, the charging current applied to the battery 20 during the rapid charging module 225 includes applying the full charging current to the battery 20 for a first period of time, such as one second, and then releasing the full charging current for a second time period, such as 50 ms. In some constructions, the controller 100 sets a first backup timer to a first predetermined time limit, such as approximately two hours. In these designs, the battery charger 30 will not implement the fast charge module 225 for the predetermined time limit to avoid battery damage. In other constructions, the battery charger 30 will shut down (i.e., stop charging) when the predetermined time limit expires.

In some constructions, the battery charger 30 will enter the rapid charge module 225 only when the battery voltage is in a range from the first voltage threshold V ₁ to a second predefined voltage threshold V ₂ and when the battery temperature is in a range from a second battery temperature threshold T ₂ falls to a third temperature threshold T ₃ . In some constructions, the second voltage threshold V ₂ is greater than the first voltage threshold V ₁ and the third temperature threshold T ₃ is greater than the second temperature threshold T ₂ .

In some constructions and in 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 module 225 to the battery 20, but only a one minute duty cycle of charging ("ON") and one minute of suspended charging (“OFF”) occurs. In some constructions, the controller 100 sets a backup timer to a second preferred time limit, such as four hours. In these constructions, the battery charger 30 will not implement the step charge module 220 for the predetermined time limit to avoid damaging the battery.

In some constructions, the battery charger 30 will only enter the stepper charger module 220 when the battery voltage is in a range from the first voltage threshold V ₁ to the second voltage threshold V ₂ and when the battery temperature is in a range from the first temperature threshold T ₁ to the second temperature threshold _T2 falls. In some constructions, the second voltage threshold V ₂ is greater than the first voltage threshold V ₁ and the second temperature threshold T ₂ is greater than the first temperature threshold T ₁ .

In some constructions and in some aspects, the charging current applied to the battery 20 during the maintenance module 230 includes applying a full charging current to the battery 20 only when the battery voltage falls to a certain predefined threshold. In some constructions, the threshold is approximately 4.05 V/cell +/- 1% per cell. In some constructions, the battery charger 30 only enters the maintenance module 230 when the battery voltage is in the range of the second voltage threshold V ₂ to the third voltage threshold V ₃ is included, and when the battery temperature falls within a range from the first temperature threshold T ₁ to the third temperature threshold T ₃ .

In some constructions and in some aspects, the controller 100 implements the various charging modules 220 to 230 based on various battery conditions. In some constructions, each charging module 220 to 230 includes the same charging algorithm (e.g., a full charging current application algorithm). Each loading module 220 to 230 implements, repeats, or includes the loading algorithm in different ways. An example of a charging algorithm is the charging current algorithm as shown in flowchart 250 of 12 is shown as discussed below.

Like in the 5a and 5b As shown, charging operation 200 begins when a battery, such as battery 20, is inserted into or electrically connected to battery charging device 30 in step 305. In step 310, controller 100 determines whether a stable input of power, such as power source 130, is applied to or connected to battery charger 30. As in 5a As shown, the same operation (that is, step 305 preceding step 310) occurs when power is applied after battery 20 has been electrically connected to battery charger 30.

If the controller 100 determines that there is no stable input of applied power, the controller 100 does not activate the display 110 and no charge is applied to the battery 20 in step 315. In some constructions, the battery charger 30 draws a small discharge current in step 315. In some constructions, the discharge current is less than about 0.1 mA.

If the controller 100 determines that stable power is being applied to the battery charger 30 in step 310, operation 200 proceeds to step 320. In step 320, controller 100 determines whether all connections between battery terminals 45, 50, and 55 and battery charger terminals 80, 85, and 90 are stable. If the connections in step 320 are not stable, control 100 proceeds to step 315.

If the connections are stable in step 320, the controller 100 identifies the chemical makeup of the battery 20 via the measurement terminal 55 of the battery 20 in step 325. In some constructions, a resistance measurement wire from the battery 20 shows as being measured by the controller 100 that the battery 20 has a chemical structure made of NiCd or NiMH. In some constructions, the controller 100 will measure the resistance of the resistance test lead to determine the chemical makeup of the battery 20. For example, in some designs, if the resistance of the test lead falls within a first range, the chemical makeup of the battery 20 is NiCd. If the resistance of the measuring line falls into a second range, then the chemical structure of the battery 20 consists of NiMH.

In some constructions, NiCd batteries and NiMH batteries are charged by the battery charger 30 using a single charging algorithm that is different from a charging algorithm implemented for batteries having a Li-based chemical structure. For example, in some designs, the only charging algorithm for NiCd and NiMH batteries is an existing charging algorithm for NiCd/NiMH batteries. In some constructions, the battery charger 30 uses the only charging algorithm for charging NiCd batteries and NiMH batteries but terminates the charging process for NiCd batteries with a different termination scheme than the termination scheme used to terminate charging for NiMH batteries . In some constructions, the battery charger 30 terminates charging for NiCd batteries when a negative change in battery voltage (e.g., -dV) is detected by the controller 100. In some constructions, the battery charger 30 terminates charging for NiMH batteries when a change in the temperature of the battery over time (e.g., ΔT/dt) reaches or exceeds a predefined termination threshold.

In some designs, NiCd and/or NiMH batteries are charged using a constant current algorithm. For example, the battery charger 30 can use the same charging circuit include charging different batteries that have different battery chemistry, such as NiCd, NiMH, Li-ion and the like. In an exemplary construction, the charging device 30 may use the charging circuitry to apply the same full charging current to NiCd and NiMH batteries because Li-ion batteries use a constant current algorithm instead of pulse charging. In another exemplary construction, the battery charger 30 may scale the full charging current through the charging circuit according to the chemical makeup of the battery.

In other designs, the controller 100 does not determine the exact chemical makeup of the battery 20. Instead, the controller 100 implements a charging module that can effectively charge both NiCd batteries and NiMH batteries.

In other designs, the resistance of the test lead could indicate that the battery 20 has a Li-based chemical makeup. For example, if the resistance of the measuring line falls into a third range, the chemical structure of the battery 20 is based on Li.

In some constructions, a serial communication link between the battery charger 30 and the battery 20 established through the measurement terminals 55 and 90 indicates that the battery 20 has a Li-based chemical structure. When a serial communication link is established in step 325, a microprocessor or controller, such as controller 64 in battery 20, sends information relating to battery 20 to controller 100 in battery charger 30. Such information between the Battery 20 and the battery charging device 30 is transmitted, the chemical structure of the battery, the battery nominal voltage, the battery capacity, the battery temperature, individual cell voltages, the number of charging cycles, the number of discharging cycles, the status of a protection circuit or a network (for example activated, blocked , unlocked etc.) etc. include.

In step 330, the controller 100 determines whether the chemical makeup of the battery 20 is Li based or not. If the controller 100 determines in step 330 that the battery 20 has a NiCd or NiMH chemical makeup, then operation 200 proceeds to the NiCd/NiMH charging algorithm in step 335.

If the controller 100 determines in step 330 that the battery 20 has a Li-based chemical makeup, then operation 200 proceeds to step 340. In step 340, the controller 100 resets any battery protection circuit, such as a switch, included in the battery 20 and determines the voltage rating of the battery 20 over the communication link. In step 345, the controller 100 adjusts the analog-to-digital converter (“A/D”) to the appropriate level based on the nominal voltage.

In step 350, controller 100 measures the current voltage of battery 20. If a measurement has been made, controller 100 determines in step 355 whether the voltage of battery 20 is greater than 4.3 volts/cell. If the battery voltage is greater than 4.3 volts/cell in step 355, operation 200 continues to the defect set module 205 in step 360. The defect set module 205 is discussed below.

If in step 355 the battery voltage is not greater than 4.3 volts/cell, the controller 100 measures the temperature of the battery in step 365 and determines in step 370 whether the temperature of the battery falls below -20°C or 65°C exceeds. If in step 370 the temperature of the battery is below -20°C or above 65°C, then operation 200 proceeds to the temperature-out-of-range module 210 in step 375. The temperature-out-of-range module 210 is discussed below.

If in step 370 the temperature of the battery is not less than -20°C and does not exceed 65°C, then the controller 100 determines in step 380 (the in 5b shown) whether the temperature of the battery falls within the range between -20°C and 0°C. If the temperature of the battery falls within the range between -20°C and 0°C in step 380, operation 200 proceeds to step 385. In step 385, controller 100 determines whether the battery voltage is less than 3.5 volts/cell. If the voltage of the battery is less than 3.5 volts/cell, operation 200 goes to the trickle charge module 215 in step 390. The trickle charge module 215 is discussed below.

If the voltage of the battery is not less than 3.5 volts/cell in step 385, the controller 100 determines in step 395 whether the voltage of the battery is in the voltage range of 3.5 volts/cell to 4.1 volts/cell is. If the battery voltage is not within the voltage range of 3.5 volts/cell to 4.1 volts/cell is in step 395, operation 200 proceeds to maintenance module 230 in step 400. Maintenance module 230 is discussed below.

If the voltage of the battery is in the voltage range of 3.5 volts/cell to 4.1 volts/cell in step 395, the controller 100 clears a counter, such as a charge counter, in step 405. If the load counter is cleared in step 405, operation 200 continues to step load module 220 in step 410. The step load module 220 and load counter are discussed below.

Return to step 380 where, if the temperature of the battery is not in the range of -20°C and 0°C, controller 100 determines in step 415 whether the battery voltage is less than 3.5 volts/cell. If the voltage in step 415 is less than 3.5 volts/cell, operation 200 continues to trickle charge module 215 in step 420.

If the voltage of the battery is not less than 3.5 volts/cell in step 415, then the controller 100 determines in step 425 whether the voltage of the battery is in the voltage range of 3.5 volts/cell to 4.1 volts/cell is. If the voltage of the battery in step 425 is not in the voltage range of 3.5 volts/cell to 4.1 volts/cell, then operation 200 continues to maintenance module 230 in step 430.

If the voltage of the battery is in the voltage range of 3.5 volts/cell to 4.1 volts/cell in step 425, then control clears a counter, such as the charge counter, in step 435. If the charge counter was cleared in step 435, operation 200 continues in step 440 to the quick charge module 225. The quick charge module 225 is discussed below.

6 is a flowchart depicting the operation of the defect set module 205. Operation of the module 205 begins when the main loading operation 200 enters the defect set module 205 in step 460. The controller 100 interrupts the charging current in step 465 and activates the indicator 110, like the first LED, in step 470. In the illustrated construction, the controller 100 controls the first LED to flash at a rate of approximately 4 Hz. If display 110 is activated in step 470, module 205 ends in step 475, and operation 200 may also end.

7 is a flowchart showing the operation of the temperature-out-of-range module 210. Operation of the module 210 begins when the main charging operation 200 enters the temperature-out-of-range module 210 in step 490. The controller 100 interrupts the charging current in step 495 and activates the indicator 110, like the first LED, in step 500. In the illustrated construction, the controller 100 controls the first LED to flash at a rate of approximately 1 Hz to alert a user to show that the battery charger 30 is currently in the temperature-out-of-range module 210. When the display 110 is activated in step 500, the operation 200 leaves the module 210 and returns to where the operation 200 left.

8th is a flowchart showing the trickle charge module 215. Operation of the module 215 begins when the main charge operation 200 enters the trickle charge module 215 in step 520. The controller 100 activates the display 110, such as the first LED 115 in step 525, to indicate to a user that the battery charger 30 is currently charging the battery 20. In the illustrated construction, the controller 100 activates the first LED 115 so that it appears constantly on.

If the display 110 was activated in step 525, the controller 100 initializes a counter, such as a trickle charge counter, in step 530. In the construction shown, the trickle charge counter has a counting limit of twenty.

In step 540, the controller 100 begins to apply two one second (1 second) full current pulses to the battery 20 and then stops charging for fifty seconds (“50 seconds”). In some designs there are 50 ms time intervals between 1 second pulses.

In step 545, the controller 100 measures the voltage of the battery when a charging current is applied to the battery 20 (e.g., during times of power on) to determine whether the voltage of the battery exceeds 4.6 volts/cell. If the voltage of the battery exceeds 4.6 volts/cell during the power-on times in step 545, the module 215 proceeds to the defect set module 205 in step 550 and would end in step 552. If the voltage of the battery does not exceed 4.6 volts/cell during the current on in step 545, the controller 100 measures in step 555 the temperature of the battery and the voltage of the battery when no charging current is being applied to the battery 20 (for example, during times of power off).

In step 560, controller 100 determines whether the temperature of the battery falls below -20°C or exceeds 65°C. If in step 560 the temperature of the battery is below -20°C or above 65°C, the module 215 proceeds to the temperature-out-of-range module 210 in step 565 and would end in step 570. If the temperature of the battery is not below -20°C in step 560 or if it is not above 65°C, then the controller 100 determines in step 575 whether the voltage of the battery is in the range of 3.5 volts/cell to 4.1 volts/cell.

If the voltage of the battery is in the range of 3.5 volts/cell to 4.1 volts/cell in step 575, the controller 100 determines in step 580 whether the temperature is in the range of -20°C to 0°C is included. If the temperature of the battery is in the range of -20 ° C to 0 ° C in step 580, the module 215 goes to the fast charging module 225 in step 590.

If the voltage of the battery is not in the range of 3.5 volts/cell to 4.1 volts/cell in step 575, the controller 100 increments the trickle charge counter in step 595. In step 600, the controller 100 determines whether the trickle charge counter has reached the count limit, which is, for example, twenty. If the counter has not reached the counter limit in step 600, the module 215 proceeds to step 540. If the counter has reached the counter limit in step 600, the module 215 proceeds to the defect set module 205 in step 605 and would end in step 610.

9 is a flowchart showing the step load module 220. Operation of the module 220 begins when the main load operation 200 enters the step load module 220 in step 630. The controller 100 activates the display 110, such as the first LED 115, in step 635 to indicate to a user that the battery charger 30 is currently charging the battery 20. In the illustrated construction, the controller 100 activates the first LED 115 so that it appears constantly on.

In step 640, the controller 100 starts a first timer or a charging timer. In the construction shown, the charging process meter counts down from one minute. In step 645, the module 220 proceeds to the charging current algorithm 250. When the charge current algorithm 250 is performed, the controller 100 determines whether the charge counter has reached the count limit, such as 7200, in step 650. If the load counter has reached the count limit in step 650, the module 220 proceeds to the defect set module 205 in step 655 and the module 220 would end at step 660.

If the charge counter has not reached the count limit in step 650, the controller 100 determines in step 665 whether the waiting time between current pulses (as will be described below) is greater than or equal to a first waiting time threshold, such as two seconds. If the waiting time is greater than or equal to the first waiting time threshold in step 665, the controller 100 activates the display in step 670, for example turning off the first LED 115 and activating the second LED 120 so that it flashes at approximately 1 Hz. If the waiting time is not greater than or equal to the first waiting time threshold in step 665, the module 220 proceeds to step 690, which is discussed below.

If the display 110 is activated in step 670, the controller 100 determines in step 675 whether the waiting time between current pulses is greater than or equal to a second waiting time threshold, for example five seconds. If the waiting time is greater than or equal to the second waiting time threshold in step 675, the controller 100 changes the display 110 in step 680, for example by activating the second LED 120 so that the second LED 120 appears to be constantly on. Module 220 then proceeds to maintenance module 230 in step 685.

If the wait time is not greater than or equal to the second wait time threshold in step 675, then controller 100 determines in step 690 whether the battery temperature is greater than 0°C. If the battery temperature is greater than 0°C in step 690, the module 220 proceeds to the fast charging module 225 in step 695. If the battery temperature is not greater than 0°C in step 690, then control determines in step 700 whether the charging timer has expired.

If the charging timer has not expired in step 700, the module 220 proceeds to the charging current algorithm 250 in step 645. If the charging timer expires in step 700, the controller 100 activates a second timer or a non-charging timer in step 705 and suspends charging. In step 710, controller 100 determines whether the no charge timer is off is running. If the no charge timer has not expired in step 710, the controller 100 waits a predetermined time in step 715 and then returns to step 710. If the no charge timer expires in step 710, the module 220 returns to step 640 to restart the charge timer.

10 is a flowchart showing the fast charging module 225. The operation of the module 225 begins when the main charging operation 200 enters the fast charging module in step 730. The controller 100 activates the display 110, such as the first LED 115 in step 735, to indicate to a user that the battery charger 30 is currently charging the battery 20. In the illustrated construction, the controller 100 activates the first LED 115 so that it appears to be constantly on.

In step 740, module 225 proceeds to charging current algorithm 250. When the charge current algorithm 250 is executed, the controller 100 determines in step 745 whether the charge counter equals the count limit (e.g., 7200). If the load counter has reached the count limit in step 650, then module 220 proceeds to defect set module 205 in step 750, and module 220 would end at step 755.

If the load count does not meet the count limit in step 745, the controller 100 determines in step 760 whether the waiting time between current pulses is greater than or equal to the first waiting time threshold (e.g., two seconds). If the waiting time is greater than or equal to the first waiting time threshold in step 760, the controller 100 activates the display 110 in step 765, for example turning off the first LED 115 and activating the second LED 120 to flash at approximately 1 Hz. If the waiting time is not greater than or equal to the first waiting time threshold in step 760, the module 225 proceeds to step 785, discussed below.

If the display is activated in step 755, the controller 100 determines in step 770 whether the waiting time between current pulses is greater than or equal to a second waiting time threshold (e.g., fifteen seconds). If the waiting time is greater than or equal to the second waiting time threshold in step 770, the controller 100 changes the display 110 in step 775, for example activating the second LED 120 so that the second LED 120 appears constantly on. Module 225 then proceeds to the maintenance module in step 780.

If the waiting time is not greater than or equal to the second waiting time threshold in step 770, the controller 100 determines whether the battery temperature in the range of -20 ° C to 0 ° C is included in step 785. If the battery temperature is in range at step 785, module 225 proceeds to step charge module 220 at step 790. If the temperature of the battery is not included in this range in step 785, the module 225 goes back to the charging current algorithm 250 in step 740.

11 is a flowchart showing the maintenance module 230. Operation of the module 230 begins when the main load operation 200 enters the maintenance module 230 in step 800. The controller 100 determines in step 805 whether the voltage of the battery is in the range of 3.5 volts/cell to 4.05 volts/cell. If the battery voltage is not in range in step 805, controller 100 continues in step 805 until the battery voltage is in range. If the battery voltage is within range in step 805, the controller 100 initializes a maintenance timer in step 810. In some designs, the maintenance timer counts down from thirty minutes.

In step 815, controller 100 determines whether the temperature of the battery falls below -20°C or exceeds 65°C. If the temperature of the battery falls below -20°C or exceeds 65°C in step 815, the module 230 proceeds to the temperature-out-of-range module 210 in step 820 and the module would end in step 825. If the temperature of the battery does not fall below -20°C or exceed 65°C in step 815, the module 230 proceeds to the charging current algorithm 250 in step 830.

When the charging current algorithm 250 is performed in step 830, control determines in step 835 whether the maintenance timer has expired. If the maintenance timer expires, the module 230 proceeds to the defect set module 840 at step 840 and the module 230 would end at step 845. If the maintenance timer has not expired in step 835, then in step 850 the controller 100 determines whether the waiting time between power pulses is greater than or equal to a first predefined maintenance waiting period, such as fifteen seconds.

If the waiting time in step 850 is greater than the first predetermined maintenance waiting time, the module 230 proceeds to step 805. If the waiting time in step 850 is not greater than or equal to the first predetermined maintenance waiting time, then the module 230 proceeds to the charging current algorithm in step 830. In some constructions, the battery charger 30 will remain in the maintenance module 230 until the battery pack 20 is removed from the battery charger 30.

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

If the voltage of the battery is greater than 4.6 volts/cell at step 880, the algorithm 250 proceeds to the defect set module 205 at step 885 and the algorithm 250 would end at step 890. If the battery voltage is not greater than 4.6 volts/cell in step 880, the controller 100 interrupts the charging current, increments a counter, such as the charging current counter, and stores the count in step 895.

In step 900, the controller 100 determines whether the temperature of the battery falls below -20°C or exceeds 65°C. If the temperature of the battery falls below -20°C or exceeds 65°C in step 900, the algorithm 250 proceeds to the temperature-out-of-range module 205 in step 905 and the algorithm 250 will end in step 910 . If the temperature of the battery does not fall below -20° C. or exceeds 65° C. in step 900, the controller 100 measures the battery voltage in step 915 when the charging current is not supplied to the battery 20.

In step 920, controller 100 determines whether the voltage of the battery is less than 4.2 volts/cell. If the voltage of the battery is less than 4.2 volts/cell in step 920, the algorithm 250 proceeds to step 875. If the battery voltage is not less than 4.2 volts/cell in step 920, the controller 100 waits in step 925 until the battery voltage is approximately 4.2 volts/cell. In step 925, the controller 100 also saves the waiting time. The algorithm 250 ends at step 930.

In another construction, the full charge current or pulse applied by the battery charger 30 may be scaled according to the individual cell voltages in the battery 20. This implementation is made with reference to the 4 and 16 described.

As in 4 is shown, the controller 100 in the battery charging device 30 can send or receive information to the microcontroller 64 in the battery 20. In some constructions, the microcontroller 64 may monitor various battery characteristics during charging, including the voltages or current states of charge of each of the battery cells 60, either automatically or in response to a command from the battery charger. The microcontroller 64 may _monitor certain battery characteristics and process or average measurements during periods of charging current (i.e., “power on” periods). In some designs, the amount of time with charging current on may be approximately one second (“1-s”). During periods of time T _off in which no charging current is flowing (i.e., in periods of “power off”), information regarding certain battery characteristics (e.g., the voltages of the cells or the state of charge of the cells) may be transmitted from the battery 20 to the charging device 30 become. In some designs, the power off period T _off is approximately 50 ms. The battery charger 30 may process the information sent from the battery 20 and modify the power-on periods T _on accordingly. For example, if one or more battery cells 60 have a higher current state of charge than the remaining battery cells 60, the battery charging device 30 may reduce the subsequent periods T _on with current on to prevent overcharging of the one or more battery cells with a higher charge.

In some constructions, the battery charger 30 may compare each individual cell voltage to an average cell voltage, and if the difference between the individual cell voltage and the average cell voltage is equal to or exceeds a predefined threshold (e.g., an imbalance threshold), then the charger 30 may use the cell as identify a cell that has a higher state of charge. The battery charger 30 may modify the power-on period T _on . In other designs, the battery charger may determine the state of charge for a specific battery cell (such as a battery cell identified as a higher voltage cell was) during the power-on period based on the information received from the battery 20. In these designs, if the estimate of the current state of charge for the cell exceeds a threshold, the battery charger 30 may modify the duration of the power-on period T _on .

For example, as in 16 As shown, the battery charger 30 instructs the battery 20 to average the cell voltage measurements taken during the next power-on period T _on1 . The command can be sent with the power off during the first period T _off1 . Thus, during the first time period T _on1 with the power switched on, the microcontroller 64 measures the cell voltages as well as other battery parameters and averages them. During the next power-off period T _off2 , the battery 30 may transmit the averaged measurements to the battery charger 30. In some constructions, the battery 20 may send eight averaged measurements, such as an averaged set state of charge measurement and an averaged individual cell state of charge for each of the seven battery cells 60. For example, the battery 20 may send the following information: cell 1 14%, cell 2 14%, cell 3 15%, cell 4 14%, cell 5 16%, cell 6 14%, cell 7 14% and voltage of the set (for example cells 1 to 7) 29.96 volts. In this example, the battery charger 30 identifies the cell 5 as a higher battery cell. The charger 30 also records the battery voltage as measured by both the battery microcontroller 64 and the battery charger 30. In this example, the battery charger 30 measures the voltage of the battery to be approximately 30.07 volts. The battery charger 30 calculates the difference in measurements of the battery's voltage (e.g., 110 mV) and determines the voltage drop across the terminals and conductors to be approximately 110 mV.

wobei V_Batterie/la die Spannung der Batterie 20 als Messung durch die Ladevorrichtung 30 ist, wobei V_Anschlüsse der Spannungsabfall über den Anschlüssen (beispielsweise 110 mV) ist, und wobei V_Zelle die Spannung der Zelle, die als ein Prozentsatz der Batteriespannung geschätzt wird, ist. Wenn die Schätzung der Spannung der Zelle 5 einen Schwellwert überschreitet, dann kann die Batterieladevorrichtung 30 den nachfolgenden Zeitabschnitt T_on3 mit eingeschaltetem Strom modifizieren. Wie in 16 gezeigt ist, identifiziert die Ladevorrichtung 30 die Zelle 5 als eine hohe Batteriezelle und modifiziert den nachfolgenden Zeitabschnitt T_on3 mit eingeschaltetem Strom so, dass er ungefähr 800 ms beträgt. Somit ist die Länge T₂ des Stroms im Zeitabschnitt T_on3 kleiner als die Länge T₁ der vorherigen Zeitabschnitte T_on1 und T_on2 mit eingeschaltetem Strom.During the subsequent time period T _on2 with the power on, the battery charger 30 “estimates” the voltage of the cell 5. For example, the battery charger 30 samples the measurements of the voltage of the battery 20 and for each measurement of the battery voltage it estimates the state of charge for the cell 5 according to the following equation: $$\left({\text{v}}_{\text{battery}/\text{1a}}-{\text{v}}_{\text{Ancl}\ddot{\text{u}}\text{sse}}\right)\times {\text{v}}_{\text{cell}}$$

where V _battery/la is the voltage of the battery 20 as measured by the charging device 30, where V _terminals is the voltage drop across the terminals (e.g. 110 mV), and where V _cell is the voltage of the cell estimated as a percentage of the battery voltage , is. If the estimate of the cell 5 voltage exceeds a threshold, then the battery charger 30 may modify the subsequent power-on period T _on3 . As in 16 As shown, the charging device 30 identifies the cell 5 as a high battery cell and modifies the subsequent power-on period T _on3 to be approximately 800 ms. Thus, the length T ₂ of the current in the time period T _on3 is smaller than the length T ₁ of the previous time periods T _on1 and T _on2 with the current switched on.

In some constructions, the charging device 30 sets the subsequent power-on periods (e.g., T _on4-5 ) to approximately the length T ₂ of the previous power-on period T _on3 (e.g., 800 ms). If cell 5 (or another cell) is further identified as a high cell, then charging device 30 may vary the length of the subsequent power-on period (e.g., T _on6 ) from, for example, the length _T2 (e.g., approximately 800 ms) to Modify length T ₃ (e.g. approximately 600 ms).

Another schematic diagram of the battery 20' is shown schematically in 13 shown. The battery 20' is similar to the battery 20, and common elements are designated by the same reference numerals "'".

In some constructions, the circuit 62' includes an electrical component, such as an identification resistor 950, and the identification resistor 950 may have a set resistance. In other constructions, the electrical component may be a capacitor, an inductor, a transistor, a semiconductor element, an electrical circuit, or other component that has a resistance or that can send electrical signals, such as a microprocessor, a digital logic component, and 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 voltage rating and the chemical makeup of the battery cell(s) 60'. A measuring connection 55 'can be electrically connected to the identification resistor 950.

The battery 20', which is shown schematically in 13 shown may be electrically connected to an electrical device such as a battery charger 960 (also shown schematically). The battery charger 960 may include a positive terminal 964, a negative terminal 968, and a measurement terminal 972. Each terminal 964, 968, 972 of the battery charger 960 can (respectively) be electrically connected to the corresponding terminal 45', 50', 55' of the battery 20'. The battery charger 960 may also include a circuit that includes electrical components such as a first resistor 976, a second resistor 980, a semiconductor electronic device or semiconductor 984, a comparator 988, and a processor, microcontroller, or controller (not shown). . In some constructions, semiconductor 984 may include a transistor that can operate in saturation or an "ON" state and that can operate in an off or "OFF" state. In some constructions, the comparator 988 may be a dedicated voltage monitor, a microprocessor, or a processing unit. In other constructions, the comparator 988 may be included in the controller (not shown).

In some constructions, the controller (not shown) may be programmed to identify the resistance of the electrical component in the battery 20', such as the identification resistor 958. The controller may also be programmed to determine one or more characteristics of the battery 20', such as the chemical makeup of the battery and the voltage rating of the battery 20'. As previously mentioned, the resistance value of the identification resistor 958 may correspond to an assigned value associated with one or more certain battery characteristics. For example, the resistance value of the identification resistor 958 may be included in a range of resistance values that correspond to the chemical makeup and voltage rating of the battery 20'.

In some constructions, the controller may be programmed to recognize a variety of resistance ranges of the identification resistor 958. In these constructions, each region corresponds to a chemical structure of a battery, such as NiCd, NiMH, Li-ion and the like. In some designs, the controller may recognize additional resistance ranges, each corresponding to a different battery chemistry or other battery characteristics.

In some designs, the controller may be programmed to recognize a variety of voltage ranges. The voltages included in the voltage ranges may correspond to or depend on the resistance value of the identification resistor 958 so 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 be further selected to be unique to each possible voltage rating of the battery 20'. For example, in a range of resistance values, a first assigned resistance value may correspond to a nominal voltage of 21 volts, a second assigned resistance value may correspond to a nominal voltage of 16.8 volts, and a third assigned resistance value may correspond to a nominal voltage of 12.6 volts. In some designs, there may be more or fewer assigned resistance values, each corresponding to a different possible voltage rating of the battery 20' associated with the resistance range.

In the exemplary implementation, the battery 20′ is electrically connected to the battery charger 960. To identify a first battery characteristic, semiconductor 984 switches to the “ON” state under the control of additional circuitry (not shown). When semiconductor 984 is in the "ON" state, identification resistor 958 and resistors 976 and 980 create a voltage divider network. The network establishes a voltage V _A at a first reference point 992. If the resistance of resistor 980 is significantly lower than the resistance of resistor 976, then voltage V _A will depend on the resistance values of identification resistor 958 and resistor 980. In this implementation, the voltage V _A is in a range determined by the resistance of the identification resistor 958. The controller (not shown) measures the voltage V _A at the first reference point 992 and determines the resistance value of the identification resistor 958 based on the voltage V _A . In some designs, the controller compares voltage V _A to a variety of voltage ranges to determine battery characteristics.

In some designs, the first battery characteristic to be identified may include the chemical makeup of the battery. For example, any resistance value below 150 kOhm may indicate that the battery 20' has a NiCd or NiMH chemical makeup, and any resistance value of approximately 150 kOhm or above may indicate that the battery 20' has a Li or Li-ion chemical makeup . Once the controller has determined and identified the chemical makeup of the battery 20', an appropriate charging algorithm or method can be selected. In other designs there are more resistance ranges than in the example above, each corresponding to a different chemical makeup of the battery.

Continuing with the example implementation, to identify a second battery characteristic, the semiconductor 984 switches to the “OFF” state under the control of the additional circuitry. When semiconductor 984 switches to the “OFF” state, identification resistor 958 and resistor 976 create a voltage divider network. The voltage V _A at 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 a 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 a voltage V _REF at a third reference point 996 is. If the voltage V _A at the first reference point 992 exceeds the fixed voltage V _REF at the third reference point 996, an output V _OUT of the comparison device 988 changes its state. In some constructions, the V _OUT output may be used to terminate charging or to serve as an indicator to begin additional functions such as a maintenance routine, a balancing routine, a discharge function, additional charging schemes, and the like. In some designs, the voltage V _REF may be a fixed reference voltage.

wobei R₁₀₀ der Widerstandswert des Identifikationswiderstands 958 ist, wobei R₁₃₅ der Widerstandswert des Widerstands 976 ist, wobei V_BATT die Nennspannung der Batterie 20' ist, und wobei V_REF eine feste Spannung, wie beispielsweise ungefähr 2,5 Volt, ist. Beispielsweise kann im Bereich der Widerstandswerte für den (oben angegebenen) chemischen Aufbau in Form von Li-Ionen, ein Widerstandswert von ungefähr 150 kOhm für den Identifikationswiderstand 958 einer Nennspannung von ungefähr 21 Volt entsprechen, ein Widerstandswert von ungefähr 194 kOhm kann einer Nennspannung von ungefähr 16,8 Volt entsprechen, und ein Widerstandswert von ungefähr 274,7 kOhm kann einer Nennspannung von ungefähr 12,6 Volt entsprechen. In anderen Konstruktionen können mehr oder weniger zugewiesene Widerstandswerte zusätzlichen oder unterschiedlichen Nennspannungswerten des Batteriesatzes entsprechen.In some constructions, the second battery characteristic to be identified may include a rated voltage of the battery 20'. For example, a general equation for calculating the resistance value for the identification resistor 958 may look like this: $${\text{<figure-callout id="100" label="R" filenames="DE000010354874B4\_0006.png" state="{{state}}">R</figure-callout>}}_{100}=\left({\text{v}}_{\text{REF}}\cdot {\text{R}}_{135}\right)/\left({\text{v}}_{\text{BATT}}-{\text{v}}_{\text{REF}}\right)$$

where R ₁₀₀ is the resistance of identification resistor 958, where R ₁₃₅ is the resistance of resistor 976, where V _BATT is the nominal voltage of battery 20', and where V _REF is a fixed voltage, such as approximately 2.5 volts. For example, in the range of resistance values for the Li-ion chemical structure (noted above), a resistance value of approximately 150 kOhm for the identification resistor 958 may correspond to a nominal voltage of approximately 21 volts, a resistance value of approximately 194 kOhm may correspond to a nominal voltage of approximately 16.8 volts, and a resistance value of approximately 274.7 kOhm can correspond to a nominal voltage of approximately 12.6 volts. In other designs, more or less assigned resistance values may correspond to additional or different voltage ratings of the battery pack.

In the construction shown, both the identification resistor 958 and the third reference point 996 can be arranged on the “high” side of a current measuring resistor 1000. Positioning the identification resistor 958 and the third reference point 996 in this manner can reduce any relative voltage fluctuation between V _A and V _REF when a charging current is present. The voltage fluctuations may appear in the voltage V _A when the identification resistor 958 and the third reference point 996 are referenced to ground 1004 and a charging current has been applied to the battery 20'.

In some constructions, the battery charger 960 may also include a charger control function. As previously discussed, when the voltage V _A is substantially equal to the voltage V _REF (indicating that the voltage V _BATT corresponds to the nominal voltage of the battery 20'), the output V _OUT of the comparator 988 changes state. In some constructions, the charging current is no longer provided to the battery 20' when the output V _OUT of the comparator 988 changes state. If the charging current is interrupted, the battery voltage V _BATT begins to decrease. When the voltage V _BATT reaches a lower threshold, the output V _OUT of the comparator 988 changes state. If the charging current is interrupted, the battery voltage V _BATT begins to decrease. When the voltage V _BATT reaches a lower threshold value, the output V _OUT of the comparator 988 changes state again. In some constructions, the lower threshold voltage V _BATT is determined by a resistance of a hysteresis resistor 1008. The charging current is resumed when the output V _OUT of the comparator 988 changes state again. In some designs, this cycle repeats for a predetermined time, as determined by the controller, or it repeats itself for a certain number of state changes carried out by the comparison device 988. In some constructions, this cycle repeats until the battery 20' is removed from the battery charger 960.

In some constructions and in some aspects, a battery, such as battery 20, in 17 is shown, are discharged so that the battery cells 60 may not have enough voltage to communicate with a battery charger 30. As in 17 As shown, the battery 20 may include one or more battery cells 60, a positive terminal 1105, a negative terminal 1110, and one or more measurement terminals 1120a and 1120b (as in 17 shown, wherein the second measurement terminal or the activation terminal 120b may or may not be included in the battery 20). The battery 20 may also include a circuit 1130 that includes a microcontroller 1140.

As in 17 As shown, circuit 1130 may include a semiconductor switch 1180 that interrupts the discharge current when circuit 1130 (e.g., microprocessor 1140) determines or measures a condition above or below a predetermined threshold (i.e., an “abnormal battery condition”). In some constructions, switch 1180 includes an interrupt condition in which power to or from battery 20 is interrupted and a permit condition in which power to or from battery 20 is permitted. In some designs, an abnormal battery condition may include, for example, high or low battery cell temperatures, high or low battery charge levels, high or low battery cell charge levels, high or low discharge current, high or low charge current, and the like. In the illustrated constructions, switch 1180 includes a power FET or a metal oxide semiconductor FET (“MOSFET”). In other constructions, switches 1180 may be arranged in parallel. Parallel switches 1180 may be included in battery packs that provide a high average discharge current (such as battery 20 that supplies power to a circular saw, a drill, and the like).

In some constructions, if the switch 1180 does not conduct, the switch 1180 may not reset, even if the abnormal condition is no longer detected. In some constructions, circuitry 1130 (e.g., microprocessor 1140) may reset switch 180 only when an electrical device, such as a battery charger 30, instructs microprocessor 1140 to do so. As previously mentioned, the battery 20 may be discharged such that the battery cells 60 do not have enough voltage to power the microprocessor 1140 to communicate with a battery charger 30.

In some constructions, if the battery 20 cannot communicate with the charger 30, the battery charger 30 may provide a small charging current through the body diode 1210 of the switch 1180 to slowly charge the battery cells 60. If the cells 60 receive enough charging current to power the microprocessor 1140, the microprocessor 1140 may change the state of the switch 1180. That is, the battery 20 can be charged even when the switch 1180 is in the non-conductive state. As in 17 As shown, switch 180 may include body diode 1210, which in some constructions is formed integrally with a MOSFET and other transistors. In other constructions, diode 1210 may be electrically connected in parallel with switch 1180.

In some constructions, if the battery 20 cannot communicate with the charger 30, the battery charger 30 may apply a small average current through a measurement line, such as the measurement line 120a or the dedicated activation terminal 120b. The current can charge a capacitor 1150, which in turn can provide enough voltage to the microprocessor 1140 to enable operation.

The constructions described above and illustrated in the figures are presented by way of example only and are not intended to serve as a limitation on the concepts and principles of the present invention. Thus, one of ordinary skill in the art will recognize that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention.

Claims (9)

A battery charger (30) operable to charge a first battery (20) and a second battery (20), the battery charger comprising: a controller (100); and a charging circuit (95) operable to charge the first and second batteries, wherein the first battery (20) includes a first plurality of battery cells (60), each cell in the first plurality having a lithium-based chemistry and wherein the first battery has a first nominal voltage in a nominal voltage range, and wherein the second battery comprises a second plurality of battery cells, each cell in the second plurality having lithium-based chemistry, and wherein the second battery has a second nominal voltage, the second nominal voltage being different from the first nominal voltage and outside the nominal voltage range, where the total number of cells in the first plurality is different from the total number of cells in the second plurality, wherein the controller can be operated to receive information regarding an individual charge state of at least one of the first plurality of battery cells from the first battery, which is coupled to the battery charging device, whereby the control can be operated to to control the battery charging device so that it supplies the first battery coupled to the battery charging device with a charging current that is based at least in part on the individual state of charge of the at least one of the first plurality of battery cells, and to control the charging current by controlling the battery charging device so that the charging current is delivered in a plurality of pulses, wherein the plurality of pulses each have a first time period during which the charging current is supplied to the battery coupled to the battery charging device at a predefined amplitude, and a second time period during which the supply of charging current is interrupted, and to control the charging current by modifying the first time period and by controlling the second time period to a constant value. Battery charging device Claim 1 , wherein the controller is operable to detect the value of an identification component in the first battery, the value representing the first nominal voltage or the nominal voltage range. Battery charging device Claim 2 , wherein the controller is further operable to select a battery characteristic threshold for a charging function when the controller identifies the value of the identification component. A battery charging device according to any preceding claim, wherein the controller is operable to identify the value of a chemistry identification component in the first battery and wherein the value represents the lithium-based chemistry of the first battery. Battery charging device Claim 1 , further comprising at least one terminal (90), wherein the controller is operable to identify the total number of lithium-based battery cells of the first plurality when the first battery is electrically connected to the at least one terminal, and the total number of lithium-based battery cells of the to identify the second plurality when the second battery is electrically connected to the at least one connection. Battery charging device Claim 5 , wherein the charging circuit is operable to charge the first battery at least in part based on the total number of lithium-based battery cells of the first plurality when the first battery is electrically connected to the at least one terminal, and to charge the second battery at least in part based on the total number to charge the lithium-based battery cells of the second plurality when the second battery is electrically connected to the at least one terminal. Battery charging device Claim 6 , wherein the controller may further operate to determine the first battery voltage rating of the first battery based at least in part on the total number of lithium-based battery cells of the first plurality. Battery charging device Claim 7 , wherein the controller is further operable to determine the second battery voltage rating of the second battery based at least in part on the total number of lithium-based battery cells of the second plurality. A battery charging device according to any one of the preceding claims, wherein the first battery comprises a first lithium-based battery cell having a state of charge, and wherein the controller is operable to identify the state of charge of the first lithium-based battery cell, and wherein the charging circuit is further operable to to charge the first battery at least partially based on the state of charge of the first lithium-based battery cell.

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