BATTERY PACK AND CHARGER PLATFORM FOR POWER TOOL SYSTEMS INCLUDING BATTERY PACK IDENTIFICATION SCHEME
A battery pack and charger platform including a voltage coupling circuit comprising an input that receives an input voltage and an output that sends an output voltage, a voltage monitoring circuit having an input coupled to the voltage coupling circuit output and an output, and a power source having an input coupled to the voltage monitoring circuit output, the power source input receives an input voltage representative of a charge instruction.
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This application claims the benefit of U.S. patent application Ser. No. 14/181,831 filed on Feb. 14, 2014 which claims the benefit of U.S. patent application Ser. No. 13/080,787 filed on Apr. 6, 2011, now U.S. Pat. No. 8,653,787, which claims the benefit of U.S. Patent Application No. 61/321,699 filed on Apr. 7, 2010. The disclosure of the above application is incorporated herein by reference.
FIELDThe present disclosure relates to a battery pack and charger platform for power tools and an improved identification scheme for battery packs in a power tool system.
BACKGROUNDCordless products or devices which use rechargeable batteries are prevalent in the marketplace. Rechargeable batteries may be used in numerous devices ranging from computers to power tools. Since the devices use a plurality of battery cells, the battery cells are commonly packaged in a battery pack. The battery pack may in turn be used to power the devices when coupled thereto. Once depleted, the battery pack may be recharged by a battery charger.
Typically, a battery charger can only charge a specific type of battery pack as the terminal arrangement amongst different types of battery packs vary. For example, a 20 volt battery pack may have a different terminal arrangement than a 14 volt battery pack. It is appreciated that these two different battery packs may require two different battery chargers. One way to avoid the need for multiple battery chargers is to create a standard interface between different types of battery packs. In this way, it may be feasible to charge each of the different types of battery packs using the same battery charger. To ensure that the battery pack is properly charged and a proper charging algorithm is applied to battery packs having different attributes, the battery charger needs to accurately identify the type of battery pack that is coupled to the battery charger. Therefore, it is desirable to develop an improved identification scheme amongst battery packs that couple to the same battery charger.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
SUMMARYOne aspect of the disclosure is a battery charger including a voltage coupling circuit comprising an input that receives an input voltage and an output that sends an output voltage, the voltage coupling circuit configured such that if the voltage coupling circuit input voltage is equal to a first reference voltage than the voltage coupling circuit couples the voltage coupling circuit output to a second reference voltage and if the voltage coupling circuit input voltage is not equal to the first reference voltage than the voltage coupling circuit couples the voltage coupling circuit output to the voltage coupling circuit input; a voltage monitoring circuit having an input coupled to the voltage coupling circuit output and an output, and a power source having an input coupled to the voltage monitoring circuit output, the power source input receives an input voltage representative of a charge instruction.
Another aspect of the disclosure is a power supply having an input; a voltage monitoring circuit having a plurality of inputs and an output coupled to the power supply input; and a voltage coupling circuit, the voltage coupling circuit having an input coupled to a charger terminal and an output coupled to one of the plurality of voltage monitoring circuit inputs, the voltage coupling circuit configured such that if a voltage at the voltage coupling circuit input is equal to a first reference voltage than the voltage monitoring circuit input coupled the voltage coupling circuit is coupled to a second reference voltage, and if the voltage at the voltage coupling circuit input is not equal to the first reference voltage than the voltage monitoring circuit input coupled to the voltage coupling circuit is coupled to the voltage coupling circuit input.
Another aspect of the invention is an electrical combination comprising a battery comprising a plurality of cells, at least one cell tap, a plurality of battery terminals. The plurality of battery terminals include a first subset of battery terminals, each battery terminal of the first battery terminal subset is electrically coupled to a battery reference voltage, and a second subset of battery terminals, each battery terminal of the second battery terminal subset is electrically coupled to one of the at least one cell tap. The electrical combination also comprises a charger comprising a power supply including an output for providing a charging current to the battery and an input, a plurality of charger terminals. Each of the plurality of charger terminals is electrically and mechanically connected to a corresponding one of the plurality of battery terminals, the plurality of charger terminals including a first subset of charger terminals, and a second subset of charger terminals. The charger also comprises a voltage coupling circuit having a plurality of inputs and a plurality of outputs, each of the plurality of voltage coupling circuit inputs is coupled to a corresponding terminal of the first charger terminal subset, each of the plurality of voltage coupling circuit outputs has a corresponding voltage coupling circuit input. The charger also comprises a voltage monitoring circuit including an output coupled to the power supply input and a plurality of inputs, each of the plurality of voltage monitoring circuit inputs has a corresponding charger terminal, the plurality of voltage monitoring circuit inputs including a first subset of voltage monitoring circuit inputs coupled to a corresponding one of the plurality of voltage coupling circuit outputs, each input of the first voltage monitoring circuit input subset corresponding to one of the terminals of the first charger terminal subset, and a second subset of voltage monitoring circuit inputs, each input of the second voltage monitoring circuit input subset coupled to a corresponding terminal of the second charger terminal subset. The voltage coupling circuit is configured such that (a) for any input of the first voltage monitoring circuit input subset that corresponds to one of the charger terminals that is coupled to one of the terminals of the first battery terminal subset said any input of the first voltage monitoring circuit input subset is coupled to a charger reference voltage and (b) for any input of the first voltage monitoring circuit input subset that corresponds to one of the charger terminals that is coupled to one of the terminals of the second battery terminal subset said any input of the first voltage monitoring circuit input subset is coupled to the corresponding charger terminal.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTIONThe present disclosure can relate to a system of power tools of the type that is generally indicated by reference numeral 10 in
The charger control module 24 is responsible for charging the battery cells and monitoring any fault conditions which may develop during charging. In an exemplary embodiment, the charger control module 24 is implemented as software (processor-executable instructions) on a digital microcontroller. However, the charger control module 24 may be embodied in hardware or software as a digital microcontroller, a microprocessor or an analog circuit, a digital signal processor or by one or more digital ICs such as application specific integrated circuits (ASICs), for example. It is also contemplated that a portion of the charger control could reside in the battery pack.
To charge a battery pack 16, the pack 16 is operably coupled to the battery charger 18. Various techniques for detecting the presence of the battery pack may be employed. Upon detecting the battery pack 16, the battery charger 18 initiates a charging scheme. In an exemplary charging scheme, the charger 18 delivers a constant current to the battery pack 16. When the stack voltage, an individual cell or a portion of the cells reaches a target charging value, the charger 18 switches from a constant current mode to a constant voltage mode. The charger 18 continues charging in constant voltage mode until the charge current drops below a predefined threshold (e.g., 100 mA) at which time the charge current is terminated.
Cell voltages are continually being monitored at step 32 via the voltage monitoring circuit 23 during the charging process. In the exemplary embodiment, the cell voltage measurements can be made between charge cycles by the voltage monitoring circuit 23. The voltage monitoring circuit 23 is preferably configured to take individual cell measurements in a sequential manner during a span, e.g., of about 10-70 milliseconds. Individual cell measurements are in turn reported to the charger control module 24 for further assessment. In the case that the charge current is delivered continuously, cell voltage measurements are taken while the charge current is being delivered to the battery cells.
The maximum charge current will continue to be delivered to the battery pack until at least one of the battery cells reaches a target charging value (e.g., 4.15 volts) as indicated at step 33. When one or more of the battery cells reaches the target charging value, the charge current will be lowered. In an exemplary embodiment, the charge current is lowered in predefined increments at step 38 until it reaches a minimum charge current (e.g., 200 mA) that can be output by the charger. For example, the charge current may be reduced in half although other decrements are also contemplated.
The average charge current delivered to the battery cells may be lowered further by skipping charge cycles. When the charger is outputting a minimum charge current and less than all of the cells have reached the target charge value, charge cycles are skipped at step 39 to further lower the average charge current delivered to the cells. For example, skipping every other charge cycle further reduces the average charging current being delivered by the charger by 50% (e.g., from 200 mA to an average of 100 mA).
After each charge cycle, cell measurements are taken and a determination is made as to whether to lower the charge current. In the exemplary embodiment, the determination to lower the charge current is made by the charger control module 24. In response to this command, the charger control module 24 interfaces with the power supply circuit 22 to lower the charge current being delivered by the charger. When all of the battery cells have reached the target charge value, the charge current is terminated as indicated at step 35. This charging scheme is particularly suitable for battery packs having cell balancing functionality. Other types of charging schemes are contemplated within the broader aspects of this disclosure.
The battery charger 18 may be configured to charge different types of battery packs 16. For example, the battery packs 16′, 16″, 16′″ may have different number of battery cells and nominal voltage ratings, such a 12 volt, 14.4 volt, and 20 volt, respectively. In each case, the battery pack 16 includes a plurality of battery cells 20 connected in series (as shown), or multiple strings of cells connect in parallel with one another in which the cells in a given string are connect in series with each other. The number of serially-connected cells determines the nominal voltage rating for the battery pack. It is readily understood that other voltage ratings fall within the scope of this disclosure. For purposes of describing the exemplary embodiments, the battery pack 16 may be composed of cells having lithium-ion cell chemistry. Likewise, it is understood that the battery pack 16 may be composed of cells of another lithium-based chemistry, such as lithium metal or lithium polymer, or another chemistry such as nickel cadmium (NiCd), nickel metal hydride (NiMH) and lead-acid, for example.
The battery packs 16 may further include temperature sensor 25. The temperature sensor 25 is configured to measure the temperature of the battery cells. The temperature sensor 25 is in turn connected via a terminal to battery control module 24 when the battery pack 16 is operably coupled battery charger 18. The temperature sensor 25 may be implemented with negative temperature coefficient (NTC) thermistor, a positive temperature coefficient (PTC) thermistor, temperature sensing integrated circuits, thermocouples, or other temperature sensitive components. Other types of protection circuits may also be incorporated into the battery packs.
Prior to charging a given battery pack 16, the battery charger 18 identifies the type of battery pack that is coupled thereto as shown in
To identify the pack type, the charger control module 24 first measures voltage at step 51 at a plurality of designated terminals (e.g., terminals 3, 4, 6 and 7) of the battery pack. Given the voltage measurements for each terminal, the charger control module determines at step 52 how many of the designated terminals are connected to a reference voltage. In this example, designated connected to positive battery voltage (B+). The type of battery pack can then be determined based on the number of designated terminals that are connected to the reference voltage, e.g., in the manner set forth below.
In the exemplary embodiment, when the charge control module 24 determines at 53 that only one of the terminals is connected to B+ (or none of the designated terminals), the battery charger is presumed to be coupled to the pack 16′″ having five battery cells. The charge control module 24 in turn selects a charging algorithm at step 54 suitable for charging the identified battery pack 16′″. Alternatively, the charge control module 24 may set parameters (e.g., an overcharge voltage threshold for the total pack) in a generic charging algorithm that is suitable for the identified battery pack 16′″. The charge control module 24 can then interact with the power supply circuit 22 to commence charging at step 59 in accordance with the appropriate charging algorithm.
When the charge control module 24 determines at step 55 that two terminals are connected to B+ (or one designated terminal, i.e., terminal 3), the battery charger 18 is presumed to be coupled to the battery pack 16″ having four cells. When the charge control module 24 determines at step 57 that three terminals are connected to B+ (or two designated terminals, i.e., terminals 3 and 6), the battery charger 18 is presumed to be coupled to the battery pack 16′ having three cells. In either case, the charge control module 24 selects the appropriate charging algorithm 56, 58 for the identified battery pack and commences charging as indicated at step 59. It is readily understood that the charging algorithms selected can vary for the different pack types. It is further envisioned that the identification scheme set forth above could be used in conjunction with other means for identifying the type of battery pack that is coupled to the battery charger.
With continued reference to
Referring to
In the exemplary embodiment, when the charge control module 24 determines at step 63 that terminal 4 has the lowest voltage measure, the battery charger is presumed to be coupled to the pack 16′ having three cells. The charge control module 24 in turn selects a charging algorithm at step 64 suitable for charging the pack 16′. Alternatively, the charge control module 24 may set parameters (e.g., an overcharge voltage threshold for the total pack) in a generic charging algorithm that is suitable for the pack 16′. The charge control module can then commerce charging in accordance with the appropriate charging algorithm as indicated at 69.
When the charge control module determines at 65 that terminal 6 has the lowest voltage measure, the battery charger is presumed to be coupled to the pack 16″ having four cells. When the charge control module determines at 67 that terminal 3 has the lowest voltage measure, the battery charger is presumed to be coupled to the pack 16′″ having five cells. In either case, the charge control module selects the appropriate charging algorithm 66, 68 for the identified battery pack and commences charging as indicated at step 69.
While the identification schemes set forth above are used to determine the nominal voltage of the battery pack, the scheme could be used to identify other attributes of a battery pack. For instance, the identification scheme could be used to distinguish between packs having different cell chemistry. Other types of attributes, such as cell chemistry, cell supplier or cell arrangement (i.e., number of parallel cell strings) are also contemplated by this disclosure. It is further contemplated that these identification schemes could be implemented by a controller into a tool such that the tool identifies attributes of the battery pack coupled thereto.
REFERENCE NUMBER LISTING
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- 100 battery
- 112 battery cell
- 114 battery cell tap
- 116 battery terminal
- 118 battery positive voltage terminal (B+)
- 120 battery negative voltage terminal (B−)
- 160 charger
- 162 power supply
- 164 voltage monitoring circuit (VMC)
- 166 voltage coupling circuit (VCC)
- 168 charger terminals
- 170 charger positive voltage terminal (B+)
- 172 charger negative voltage terminal (B−)
- 174 voltage coupling circuit input (VCCI)
- 176 voltage coupling circuit output (VCCO)
- 178 voltage monitoring circuit input
- 180 voltage monitoring circuit output
- 182 first power supply input
- 184 second power supply input
- 186 power supply output
- 188 switching circuit
- 190 switching circuit input
- 192 switching circuit output
- 194 comparator
- 196 switching circuit first switch
- 198 switching circuit second switch
- 200 switching circuit third switch
- 202 charger output
- 300 printed circuit board (PCB) blank
- 302 first section of PCB blank
- 304 second section of PCB blank
- 306 reduced material section of PCB blank
- 308 a plurality of first through holes
- 310 a plurality of second through holes
- 312 a plurality of jumpers
- 314 a terminal block
- 316 a plurality of third through holes
- 318 terminal block housing
- 320 a plurality of contacts
The present invention may be used as part of an implementation of a battery pack and charger platform. In general, the platform will have a battery pack and a charger. Each battery pack has a plurality of battery cells. The platform will have battery packs having a maximum of N battery cells and a minimum of M battery cells. The platform will include battery packs having from M to N battery cells, inclusive. Every battery pack in the platform will have a set of battery terminals. In the preferred embodiment, the number of battery terminals in the battery terminal set is dependent upon the maximum number (N) of battery cells in the battery platform. In the preferred embodiment, the number of terminals in the battery terminal set is equal to N−1. The battery terminal set includes a first subset and a second subset of battery terminals. The number of terminals in the first and second battery terminal subsets is dependent upon the number of battery cells in a particular battery pack in a particular battery platform. The battery pack will be discussed in greater detail below. The battery pack may have other terminals and components but for purposes of this disclosure and clarity, those terminals and components will not be discussed.
The charger includes a power supply, a voltage monitoring circuit, a voltage coupling circuit and a set of charger terminals. The power supply includes a first input for coupling to an exterior power source, for example the mains line, an output for providing a charging current to an attached battery pack and a second input for receiving a command signal. The charger may have other components but for purposes of this disclosure and clarity, those components will not be discussed.
The voltage monitoring circuit includes an output coupled to the second power supply input for providing the command signal to the power supply and a set of inputs for receiving voltage signals. The number of inputs in the voltage monitoring circuit input set is dependent upon the maximum number (N) of battery cells in the platform. In the preferred embodiment, the number of inputs in the voltage monitoring circuit input set is equal to N−1. The voltage monitoring circuit input set includes a first subset and a second subset of voltage monitoring circuit inputs. In a preferred embodiment, the number of inputs in the first and second voltage monitoring circuit input subsets is dependent upon the maximum number (N) and the minimum number (M) of battery cells in a particular battery platform. In the preferred embodiment, the number of inputs in the first voltage monitoring input subset is equal to M−1. In the preferred embodiment, the number of inputs in the second voltage monitoring input subset is equal to N−M. The voltage monitoring circuit may be, for example, an overvoltage protection chip well known in the battery monitoring industry. An example is an overvoltage protection chip manufactured by Seiko Corporation. The voltage monitoring circuit will be discussed in greater detail below. The voltage monitoring circuit may have other inputs, outputs and components but for purposes of this disclosure and clarity, those inputs, outputs and components will not be discussed.
The voltage coupling circuit includes an output coupled to the second voltage monitoring circuit input subset and an input. The voltage coupling circuit also includes a set of switching circuits. The switching circuits couple the voltage coupling circuit input and output. In the preferred embodiment, the number of switching circuits in the switching circuit set is dependent upon the maximum number (N) and the minimum number (M) of battery cells in the battery platform. In the preferred embodiment, the number of switching circuits in the switching circuit is equal to N−M. The voltage coupling circuit and the switching circuits will be discussed in greater detail below. The voltage coupling circuit and the switching circuits may have other inputs, outputs and other components but for purposes of this disclosure and clarity, those inputs, outputs other components will not be discussed.
In a preferred embodiment, the number of terminals in the charger terminal set is dependent upon the maximum number (N) of battery cells in the battery platform and is equal to the number of terminals in the battery terminal set (N−1). The charger terminal set includes a first subset and a second subset of charger terminals. In a preferred embodiment, the number of terminals in the first and second battery terminal subsets is dependent upon the maximum number (N) and the minimum number (M) of battery cells in a particular battery platform. In the preferred embodiment, the number of terminals in the first charger terminal subset is equal to M−1 and the number of terminals in the second charger terminal subset is equal to N−M. The charger terminals will be discussed in greater detail below. The charger may have other terminals and components but for purposes of this disclosure and clarity, those terminals and components will not be discussed.
The platform includes a charger 160 that is capable of charging each battery pack 110 in the platform. The charger 160 includes a power supply 162, a voltage monitoring circuit (VMC) 164, a voltage coupling circuit (VCC) 166, and a set of charger terminals 168. The charger terminal set has the same number of terminals as the battery terminal set. Each charger terminal 168 is electrically and mechanically connectable to a corresponding one of the battery terminals 116. The charger terminal set includes a first subset of charger terminals. The number of charger terminals in the first charger terminal subset is equal to M−1. The charger terminal set also includes a second subset of charger terminals. The number of charger terminals in the second charger terminal subset is equal to N−M.
Referring to
The charger 160 includes the four (N−1) charger terminals 168a, 168b, 168c, and 168d. Each of the charger terminals 168a, 168b, 168c, 168d are electrically and mechanically connected to a corresponding battery terminal 116a, 116b, 116c, 116d, respectively. The charger 160 also includes a positive voltage terminal (B+) 170 and a negative voltage terminal (B−) 172, electrically and mechanically connected to the battery positive voltage terminal 118 and battery negative terminal 120, respectively. Two of the charger terminals 168a, 168a are coupled directly to the voltage coupling circuit 166. The charger terminals 168a and 168b constitute the first charger terminal subset. While there may be other components coupled between the charger terminals 168a, 168b and the voltage coupling circuit, for purposes of simplicity and clarity such other components are not illustrated. Two of the charger terminals 168c, 168d are coupled directly to the voltage monitoring circuit 164. The charger terminals 168c and 168d constitute the second charger terminal subset. While there may be other components coupled between the charger terminals 168c, 168d and the voltage monitoring circuit, for purposes of simplicity and clarity, such other components are not illustrated. What is clear is that the charger terminals of the second charger terminal subset are not coupled to the voltage coupling circuit 166. The voltage coupling circuit 166 includes an input 174.
Referring now to
In the preferred exemplary embodiment, the voltage coupling circuit 166 operates as follows. When the battery pack 110 is coupled to the charger 160, the charger terminals 168a, 168b, 168c, 168d electrically and mechanically couple to the corresponding battery terminals 116a, 116b, 116c,116d, respectively. When the battery pack 110 is connected to the charger 160 the voltage on the battery terminal 116a is placed on the charger terminal 168a, the voltage on the battery terminal 116b is placed on the charger terminal 168b, the voltage on the battery terminal 116c is placed on the charger terminal 116c, and the voltage on the battery terminal 116d is placed on the charger terminal 116d. Furthermore, the voltage on the charger terminal 116a is placed on the voltage coupling circuit input 174a, the voltage on the charger terminal 116b is place on the voltage coupling circuit input 174b, the voltage on the charger terminal 116c is placed on the voltage monitoring circuit input 178c and the voltage on the charger terminal 116d is placed on the voltage monitoring circuit input 178d. The voltage on the voltage coupling circuit input 174a is placed on the first switching circuit input 190a and the voltage on the voltage coupling circuit input 174b is placed on the second switching circuit input 190b.
Each switching circuit 188 will now be described. With regard to the first switching circuit 188a, the voltage on the first switching circuit input 190a is placed on the input of the first comparator 194a. The first comparator 194a compares the comparator input voltage to a comparator reference voltage. If the first comparator input voltage is greater than the comparator reference voltage than the first comparator 194a places a high voltage on the first comparator output. If the comparator input voltage is less than or equal to the comparator threshold voltage than the first comparator 194a places a low voltage on the first comparator output. When the first switch 196a receives the high voltage at its control terminal the first switch 196a opens—effectively opening the connection between the switching circuit input 190a and the switching circuit output 192a. When the second switch 198a receives the high voltage at its control terminal the second switch 198a closes—effectively coupling the switching circuit output 192a to a charger reference voltage. The charger reference voltage can be a ground voltage or any other reference voltage. When the first switch 196a receives the low voltage at its control terminal the first switch 196a closes—effectively closing the connection between the switching circuit input 190a and the switching circuit output 192a. When the second switch 198a receives the low voltage at its control terminal the second switch 198a opens.
With regard to the second switching circuit 188b, it operates similarly to the first switching circuit. With regard to the second switching circuit 188b, the voltage on the second switching circuit input 190b is placed on the input of the second comparator 194b. The second comparator 194b compares the second comparator input voltage to a comparator reference voltage. If the second comparator input voltage is greater than the comparator reference voltage than the second comparator 194b places a high voltage on the second comparator output. If the second comparator input voltage is less than or equal to the comparator threshold voltage than the second comparator 194b places a low voltage on the second comparator output. The state of the third switch 200 will determine the state of the first and second switches 196b, 198b of the second switching circuit 188b.
As noted above, due to the nature of the third switch 200, if the output of the first comparator 194a is the low voltage and the output of the second comparator 194b is the high voltage, the third switch 200 will close and if the output of the first comparator 194a is the high voltage and the output of the second comparator 194b is the low voltage or the high voltage, the third switch 200 will open.
When the third switch 200 is open, the second switching circuit 188b operates in the same manner as the first switching circuit 188a. In other words, when the first switch 196b receives the high voltage at its control terminal the first switch 196b opens—effectively opening the connection between the switching circuit input 190b and the switching circuit output 192b and when the second switch 198b receives the high voltage at its control terminal the second switch 198b closes—effectively coupling the switching circuit output 192b to the charger reference voltage. When the first switch 196b receives the low voltage at its control terminal the first switch 196b closes—effectively closing the connection between the switching circuit input 190b and the switching circuit output 192b. When the second switch 198b receives the low voltage at its control terminal the second switch 198b opens.
When the third switch 200 is closed, the effect is that the control terminals of the first and second switches 196b, 198b are coupled to output of the first comparator 194a and the low voltage output by the first comparator 194a is placed on the control terminals of the first and second switches 196b, 198b of the second switching circuit 188b. As noted above, when the first switch 196b receives the low voltage at its control terminal the first switch 196b closes—effectively closing the connection between the switching circuit input 190b and the switching circuit output 192b. When the second switch 198b receives the low voltage at its control terminal the second switch 198b opens.
As noted above, the switching circuit output 192 is coupled to the voltage coupling circuit output 176 and the voltage coupling circuit output 176 is coupled to the voltage monitoring circuit input 178. As such, when the switching circuit output 192 is coupled to the charger reference voltage the corresponding voltage monitoring circuit input 178 is coupled to the charger reference voltage effectively placing the charger reference voltage on the voltage monitoring circuit input 178. Also, when the switching circuit output 192 is coupled to the switching circuit input 190 the corresponding voltage monitoring circuit input 178 is coupled to the corresponding switching circuit input 190 effectively placing the voltage at the switching circuit input 190 on the corresponding voltage monitoring circuit input 178.
In the preferred embodiment, the comparator reference voltage is predefined such that it is less than the battery reference voltage but greater than a maximum charger voltage of an individual battery cell 112. So for example, in the illustrated embodiment, the minimum that the reference voltage would be is three times the minimum of a discharged battery cell. Conventional, battery cells do not discharge to a voltage less than 2.5V. And as illustrated in
In this configuration, when the battery terminal 116 is coupled to the battery reference voltage B+ the corresponding switching circuit comparator will place a high voltage on the comparator output. And when the battery terminal 116 is coupled to a battery cell tap 112 that has a voltage that is less than the comparator reference voltage, the corresponding switching circuit comparator will place a low voltage on the comparator output. As should be noted, in the situation in the disclosed embodiment which describes a battery pack 110 have five cells, it appears that the battery cell tap 112b would have a voltage greater than the comparator reference voltage thereby placing a high voltage on the corresponding comparator output. While this is the case, the third switch 200 of the switching circuit 188 addresses this issue.
It should be noted that while voltage coupling circuit has been described with components—including the comparator and the switches—which are responsive to the noted reference voltage, other switches can be selected and the comparator can be set to other comparison voltages. In other words, a comparator that places a low voltage when coupled to the battery reference and a high voltage when not coupled to the battery reference and a first switch of the switching circuit can be selected that opens with a low voltage at the control terminal and closes with a high voltage at the control terminal and a second switch of the switching circuit can be selected that opens with a high voltage at the control terminal and closes with a low voltage at the control terminal. One of ordinary skill in the art will appreciate a variety of ways to implement the concepts disclosed herein. The specific embodiment illustrated and described should not limit the scope of the disclosure or the invention.
Referring to
Referring to
Referring to
In step 102, the particular battery pack 110 is coupled to the charger 160. In step 104, the constant F is set to N−M. In step 106, a variable f is set to 1. In step 108, it is determined whether or not the fth voltage coupling circuit input—VCCIf—is equal to the battery reference voltage. If, in step 108 it is determined that VCCIf is not equal to the battery reference voltage then in step 110 all of the VCCOf through VCCOF will be coupled to the corresponding VCCIf through VCCIF. In other words, if N=5 and M=3, in the first iteration where f=1 and F=2, if VCCI1 is equal to the battery reference voltage—because battery terminal 1161, e.g., 116a, is coupled to the battery reference voltage and battery terminal 1161 is coupled to charger terminal 1161, for example 116a, and charger terminal 1161 is coupled to VCCI1—then VCCO1 and VCCO2 will be coupled to VCCI1 and VCCl2, respectively. The process will then end.
If, in step 108 it is determined that VCCIf is equal to the battery reference voltage then in step 110 VCCOf will be coupled to the charger reference voltage. Then in step 114 it is determined if f=F. In other words, it is determined if all of the VCCI in the charger have been considered. If it is determined that f does equal F and therefore all of the VCCI in the charger have been considered, the process will end. If it is determined that f does not equal F and therefore not all of the VCCI in the charger have been considered, in step 116 f will be incremented by 1 and the next VCCI will be considered in step 108. This process will continue until all of the VCCI in the charger have been considered.
It should be noted that the voltage coupling circuit may be implemented as an analog circuit, a digital circuit, or some combination of digital and analog circuits.
The voltage monitoring circuit (VMC) [also referred to as an overvoltage protection circuit (OPC)] includes an output. The VMC maintains a voltage VMCO at the VMC output. The VMC output is coupled to an input of the power supply. Under normal operating conditions, VMCO is set to a first value, for example a low value. When VMCO is low the power supply provides a charging current to the battery coupled to the charger. If, based on the input voltages at the plurality of inputs to the VMC, the VMC measures/generates/develops an internal voltage OV greater than a preset threshold—overvoltage threshold OVTH—indicative of an overvoltage situation in one of the battery cells, than the VMC changes VMCO to a high value. When the power supply receives the VMCO high value it turns off thereby no longer providing current to the battery coupled to the charger. This is a conventional operation of an overvoltage protection chip commonly used in chargers coupled to rechargeable batteries to prevent over charging one or more of the cells of the battery or the battery in general.
Another aspect of the present invention is a method for improving the manufacturing process for a printed circuit board (PCB) assembly. Assembling a printed circuit board is a labor intensive process and as such can be very expensive. If machine assembly of the printed circuit board can be used as a substitute for human labor than the cost of the PCB assembly can typically be reduced. The present invention provides a method for reducing the amount of human labor in the manufacture of a PCB assembly.
Referring to
As illustrated in
As illustrated in
In a third step of the manufacturing process, the populated PCB is put through a wave soldering process with the soldering taking place on the opposed side of the populated PCB, as is well known in the industry. In this step, each of the contacts 320 are electrically coupled to a corresponding one of the first through holes 308 through the corresponding one of the third through holes 316, the corresponding metal trace, the corresponding one of the second through holes 310 and the corresponding one of the jumpers 312. This step can easily be accomplished by a machine.
As illustrated in
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Claims
1-19. (canceled)
20. A battery pack system, comprising:
- a set of battery packs, the battery packs set including L elements, each battery pack of the battery packs set including a different number M of battery cells, where 2≦M≦N and where L≦2 and N>L,
- each battery pack of the battery packs set including a set of battery terminals, the battery terminals set including O elements, where O<N,
- a first subset of the battery terminals set, the first battery terminals subset including P elements, where 0≦P<O, each battery terminal of the first battery terminals subset coupled to a battery reference node, and
- a second subset of the battery terminals set, the second battery terminals subset including Q elements, where Q=O−P, each battery terminal of the second battery terminals subset coupled to a battery measurement node.
21. The battery pack system of claim 20, wherein the battery reference node is a battery positive voltage node.
22. The battery pack system of claim 20, wherein the battery measurement node is a node between battery cells.
23. The battery pack system of claim 20, wherein L=3 and N=5 and O=4.
24. A battery pack comprising:
- a set of battery terminals, the battery terminals set including O elements,
- a first subset of the battery terminals set, the first battery terminals subset including P elements, where 0≦P<O, each battery terminal of the first battery terminals subset coupled to a battery reference node, and
- a second subset of the battery terminals set, the second battery terminals subset including Q elements, where Q=O−P, each battery terminal of the second battery terminals subset coupled to a battery measurement node.
25. The battery pack of claim 24, further comprising a set of battery cells, the battery cells set including M elements and where 2≦M≦N and where N>O.
26. The battery pack of claim 24, wherein the battery reference node is a battery positive voltage node.
27. The battery pack of claim 24, wherein the battery measurement node is a node between battery cells.
28. The battery pack of claim 25, wherein N=5 and O=4.
29. A battery pack and battery charger platform, comprising:
- a set of battery packs, the battery packs set including L elements, each battery pack of the battery packs set including a different number M of battery cells, where 2≦M≦N and where L≧2 and N>L,
- each battery pack of the battery packs set including a set of battery terminals, the battery terminals set including O elements, where O<N,
- a first subset of the battery terminals set, the first battery terminals subset including P elements, where 0≦P<O, each battery terminal of the first battery terminals subset coupled to a battery reference node, and
- a second subset of the battery terminals set, the second battery terminals subset including Q elements, where Q=O−P, each battery terminal of the second battery terminals subset coupled to a battery measurement node,
- a battery charger including a set of charger terminals, the charger terminals set including O elements, the battery charger configured to mechanically couple to each battery pack in the battery packs set such that each charger terminal mechanically and electrically couples to a corresponding battery terminal.
30. The battery pack and charger platform of claim 29, wherein the battery charger is configured to determine the number of battery cells in the battery pack coupled to the battery charger based on P.
Type: Application
Filed: Feb 20, 2014
Publication Date: Aug 21, 2014
Applicant: BLACK & DECKER INC. (Newark, DE)
Inventors: Brian K. Wohltmann (Shrewsbury, PA), Regina G.C. Cunanan (Baltimore, MD), Michael Cruz (Pasadena, MD), Geoffrey S. Howard (Columbia, MD)
Application Number: 14/185,420
International Classification: H02J 7/00 (20060101); G01R 31/36 (20060101);