U.S. patent application number 17/123332 was filed with the patent office on 2021-05-06 for portable drawn arc stud welder including a lithium ferrophosphate battery.
The applicant listed for this patent is Nelson Stud Welding, Inc.. Invention is credited to Stephen D. Brooks, Jeffrey Krupp, Scott J. Schraff.
Application Number | 20210129256 17/123332 |
Document ID | / |
Family ID | 1000005331794 |
Filed Date | 2021-05-06 |
![](/patent/app/20210129256/US20210129256A1-20210506\US20210129256A1-2021050)
United States Patent
Application |
20210129256 |
Kind Code |
A1 |
Schraff; Scott J. ; et
al. |
May 6, 2021 |
PORTABLE DRAWN ARC STUD WELDER INCLUDING A LITHIUM FERROPHOSPHATE
BATTERY
Abstract
A portable drawn arc stud welder apparatus with a lithium
ferrophosphate (LFP) battery and stud weld battery control system
(SWBCS) is provided for welding a stud onto a workpiece. The
portable drawn arc stud welder apparatus includes a housing, an LFP
battery disposed in the housing and including a plurality of LFP
battery cells, a weld stud gun configured to hold a stud and is
electrically connected to the LFP battery for receiving energy from
the LFP battery to pass a current through the stud and the
workpiece to form a weldment. The SWBCS is disposed in the housing
and electrically connected to the LFP battery of the portable drawn
arc stud welder apparatus. The SWBCS includes a computer, a memory,
and instructions therein to implement control and monitoring of the
operation of the portable drawn arc stud welder apparatus.
Inventors: |
Schraff; Scott J.; (Avon,
OH) ; Krupp; Jeffrey; (Vermillion, OH) ;
Brooks; Stephen D.; (Valley City, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nelson Stud Welding, Inc. |
Elyria |
OH |
US |
|
|
Family ID: |
1000005331794 |
Appl. No.: |
17/123332 |
Filed: |
December 16, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15924949 |
Mar 19, 2018 |
10906122 |
|
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17123332 |
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62472762 |
Mar 17, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23K 9/205 20130101;
B23K 9/202 20130101; B23K 9/207 20130101; B23K 9/1006 20130101;
H04W 52/0261 20130101; B23K 9/0953 20130101; B23K 9/1043
20130101 |
International
Class: |
B23K 9/20 20060101
B23K009/20; B23K 9/095 20060101 B23K009/095; B23K 9/10 20060101
B23K009/10 |
Claims
1. A portable drawn arc stud welder apparatus for welding a stud
onto a workpiece, the portable drawn arc stud welder apparatus
including: a housing; a lithium ferrophosphate (LFP) battery
disposed in the housing and including a plurality of LFP battery
cells; a weld stud gun configured to hold a stud electrically
connected to the LFP battery for receiving energy from the LFP
battery to pass a current through the stud and the workpiece to
form a weldment; a stud weld battery control system (SWBCS)
disposed in the housing electrically connected to the LFP battery
of the portable drawn arc stud welder apparatus, wherein the SWBCS
includes a processor, and a memory, and instructions therein, to
implement control and monitoring of the operation of the portable
drawn arc stud welder apparatus; the SWBCS configured to measure a
rate of change of a voltage of the LFP battery after a sequence of
consecutive welds and to determine whether the measured the rate of
change exceeds a predetermined rate of change level; the SWBCS
configured to balance the plurality of battery cells and then
measure a temperature of the LFP battery via temperature sensors
against a predetermined temperature range at least after the SWBCS
balances the plurality of battery cells; the SWBCS configured to
activate one or more fans disposed in the housing in response to
the measured temperature of the LFP battery exceeding a
predetermined temperature level and/or if a calculated welding rate
exceeds a predetermined welding rate; and the SWBCS configured to
selectively operate the one or more fans in response to the
measured temperature dropping below the predetermined temperature
level and/or if the calculated welding rate exceeds the
predetermined welding rate.
2. The portable draw arc stud welder apparatus as set forth in
claim 1 wherein the SWBCS is further configured to activate the one
or more fans if either a measured weld frequency exceeds a
predetermined weld frequency level, or a measured LFP battery
temperature rate of change exceeds a predetermined LFP battery
temperature rate of change level or if a measured average power of
the LFP battery exceeds a predetermined average power of the LFP
battery level or if the measured temperature of the LFP battery
exceeds a predetermined level, and if a measured LFP battery
current level exceeds a predetermined LFP battery current
level.
3. The portable draw arc stud welder apparatus as set forth in
claim 2, wherein the activation of the one or more fans includes a
variable speed relative to at least one of the predetermined weld
frequency level, the predetermined LFP battery temperature rate of
change level, the predetermined average power of the LFP battery
level, and the predetermined LFP battery current level.
4. The portable draw arc stud welder apparatus as set forth in
claim 1, wherein the SWBCS is further configured to activate the
one of more fans from a first speed to a second speed faster than
the first speed, if either a measured weld frequency exceeds a
predetermined weld frequency level, or a measured LFP battery
temperature rate of change exceeds a predetermined LFP battery
temperature rate of change level, or if the measured average power
of the LFP battery exceeds a predetermined average power level of
the LFP battery and the measured temperature of LFP battery 38
exceeds a predetermined temperature of the LFP battery.
5. The portable draw arc stud welder apparatus as set forth in
claim 4, wherein the activation of the one or more fans includes a
variable speed relative to at least one of the predetermined weld
frequency level, the predetermined LFP battery temperature rate of
change level, the predetermined average power level of the LFP
battery, and the predetermined temperature of the LFP battery.
6. The portable draw arc stud welder apparatus as set forth in
claim 1, wherein the SWBCS is further configured to activate the
one of more fans from a first speed to a second speed slower than
the first speed, if either a measured weld frequency is below a
predetermined weld frequency level, and a measured battery
temperature rate of change is below a predetermined temperature
rate of change level, and if a measured average power from LFP
battery is below a predetermined average power level and a measured
temperature of LFP battery is below the predetermined temperature
of LFP battery.
7. The portable draw arc stud welder apparatus as set forth in
claim 6, wherein the activation of the one or more fans includes a
variable speed relative to at least one of the predetermined weld
frequency level, the predetermined temperature rate of change
level, the predetermined average power level, and the predetermined
temperature of LFP battery.
8. The portable draw arc stud welder apparatus as set forth in
claim 1 wherein the SWBCS is further configured to deactivate the
one or more fans if either a measured weld frequency is below a
predetermined weld frequency level, and a measured battery
temperature rate of change is below a predetermined temperature
rate of change level, and if a measured average power of the LFP
battery is below a predetermined average power level and a measured
temperature of the LFP battery is below a predetermined temperature
of the LFP battery.
9. The portable draw arc stud welder apparatus as set forth in
claim 8, wherein the deactivation of the one or more fans includes
a variable speed relative to at least one of the predetermined weld
frequency level, the predetermined temperature rate of change
level, the predetermined average power level and the predetermined
temperature of the LFP battery.
10. The portable drawn arc stud welder apparatus as set forth in
claim 1 wherein the SWBCS is further configured to generate a
battery low error signal when a measured rate of change of the
voltage of the LFP battery exceeds a predetermined level.
11. The portable drawn arc stud welder apparatus as set forth in
claim 10 wherein the SWBCS is further configured to generate a
battery low error signal when the SWBCS determines that a
difference between a predetermined weld current setpoint and a
measured weld current exceeds a predetermined weld current
value.
12. The portable drawn arc stud welder apparatus as set forth in
claim 11, wherein the SWBCS is further configured to generate a low
battery error signal when the SWBCS measures the voltage of the LFP
battery and determines whether the measured voltage of the LFP
battery is below a predetermined voltage value.
13. The portable drawn arc stud welder apparatus as set forth in
claim 12, wherein the SWBCS determines a state of charge of the LFP
battery by measuring the voltage of the LFP battery and comparing
it to a predetermined LFP battery voltage level.
14. The portable drawn arc stud welder apparatus as set forth in
claim 13, wherein the SWBCS is configured to measure a charging
current of the LFP battery and determines if the measured charging
current of the LFP battery is above a predetermined charging
current level of the LFP battery.
15. The portable drawn arc stud welder apparatus as set forth in
claim 1, wherein the LFP battery includes: a plurality of battery
cells electrically connected to a plurality of battery cell busbars
for the transmission of electrical energy to and/or from the
plurality of battery cells; a plurality of battery terminal busbars
electrically connected to the plurality of battery cell busbars for
the transmission of electrical energy to and/or from the LFP
battery; a plurality of thermally conductive, electrically
insulating pads disposed between the plurality of battery cells; a
housing of the LFP battery wherein at least a portion of the
housing is configured as a heat sink; a plurality of temperature
sensors disposed about the housing of the LFP battery; and at least
one cooling duct disposed in the LFP battery and in fluid
communication with the at least one or more fans.
16. The portable drawn arc stud welder apparatus as set forth in
claim 1, wherein the SWBCS is configured to measure a voltage of
each of the plurality of battery cells of the LFP battery to
determine if the voltages of each of the plurality of battery cells
of the LFP battery is within a predetermined voltage range.
17. The portable drawn arc stud welder apparatus as set forth in
claim 16, wherein the SWBCS is configured to compare the measured
voltages of the plurality of battery cells of the LFP battery to a
predetermined voltage range of the plurality of battery cells to
deter the LFP battery mine if any of the plurality of battery cells
of the LFP battery has a measured voltage above and/or below the
predetermined voltage range.
18. The portable drawn arc stud welder apparatus as set forth in
claim 17, wherein the SWBCS is configured to balance the charge
levels of the plurality of battery cells of the LFP battery to the
predetermined voltage range if any of the plurality of battery
cells of the LFP battery has a measured voltage above and/or below
the predetermined voltage range.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent
application Ser. No. 15/924,949, filed on Mar. 19, 2018, and
entitled a "Portable Drawn Arc Stud Welder Including a Lithium
Ferrophosphate Battery", which claims priority to U.S. Provisional
Patent Application Ser. No. 62/472,762, filed on Mar. 17, 2017, the
entire disclosures of which are hereby incorporated by reference as
though set forth fully herein.
BACKGROUND OF THE DISCLOSURE
[0002] The present disclosure relates to a stud welder, and more
particularly to a lithium ferrophosphate battery-powered, portable
drawn arc stud welder.
[0003] Stud welding is a technique for welding a fastener, such as
stud or other fastener, to a base metal of a workpiece. It should
be understood that the term "stud" is used herein to refer to studs
and other fasteners in general, and is only exemplary and not
limiting. Various stud welder systems are known in the art for this
purpose. One such type of stud welder system is known as a
capacitive discharge (CD) system, which may include a charging
circuit, an energy storage device (e.g., one or more capacitors),
and a discharge circuit which extends through a weld stud gun. The
power supply for such welding systems is normally an external
source of AC power. In operation, the energy storage device is
discharged to create an arc between a stud that is connected to the
weld stud gun and the workpiece, thereby heating up the stud and
the workpiece. When the arc is complete, the weld stud gun plunges
the stud into the heated area on the workpiece to create a
weldment. However, these stud welder systems must be tethered to an
external power supply (i.e., AC power), during operation, and thus
are not portable. Also, the capacitive discharge process that these
systems use is recognized in the art, and by key regulatory codes
such as the American Welding Society (AWS) D1.1, as being
unsuitable for full strength welds required in structural
applications.
[0004] To produce full strength welds suitable for structural
applications, it is known in the art, and required by AWS D1.1
welding code, to apply a drawn arc stud welding system. A drawn arc
stud welding system may include a high capacity electrical power
converter, which may use a single phase or three phase industrial
AC power supply as an input, and may produce a high current DC
welding output. For a drawn arc system capable of welding a stud of
1.27 cm (0.5 in) diameter, this DC welding output current should be
between 800 to 900 amps, for a duration of 500 to 600
milliseconds.
[0005] Drawn arc stud welding systems may be battery powered to
achieve true portability, not needing to be connected to an input
power cable, and being small and lightweight for easy transport.
For these portable battery powered systems, the challenge for an
optimally-applied battery is to repeatedly provide the required
high weld currents, and a suitably high weld voltage, while being
as small and as light as possible.
[0006] Drawn arc stud welding systems including a battery should to
be able to produce stud welds at a rate (e.g., stud welds per
minute), that meets the expectations of experienced welders (i.e.,
operators/users). This requirement leads to the need for the
battery of the drawn arc stud welding system to have excellent
thermal management capability and to avoid overheating. The battery
needs to be intrinsically safe from commonly-understood hazards,
including exothermic runaway events, caused by overheating during
use, or impacts/punctures that may cause internal short circuits,
leading to overcurrent/overheating of the internal structure of the
battery.
[0007] Some existing portable battery-powered drawn arc stud
welding systems rely on several types of batteries, each of which
has its own application tradeoffs. For example, an existing
portable battery-powered drawn arc stud welding system may use
multiple lead acid batteries, resulting in a relatively large and
heavy portable welding system. The use of multiple lead acid
batteries, which have a relatively low specific energy (Wh/kg),
results in a portable welding system that is difficult to transport
and therefore has limitations on its applicability. The existing
portable battery-powered drawn arc stud welding system may use four
(4) 12 volt DC lead acid batteries that are each permanently
disposed with the portable battery powered drawn arc stud welding
system housing to provide the high current capacity needed for
drawn arc stud welding. The existing portable battery-powered drawn
arc stud welding system including lead acid batteries may include
an internal battery charger which further increases the size and
weight of the resultant portable battery-powered drawn arc stud
welding system. As lead acid batteries may require a relatively
long recharge period, such a system may suffer from extended
periods of lost operational time due to this limitation. Aside from
the aforementioned limitations of lead acid batteries, additional
limitations include battery degradation due to excessive heat,
battery aging, excessive discharge, slow rate of charge, short
cycle life, and possible hazardous conditions due to leakage of
acid and/or hydrogen gas. In addition, lead is a toxic metal, which
creates additional hazards for environmentally appropriate
disposal.
[0008] Other battery types for portable battery-powered drawn arc
stud welding systems have negative attributes that limit their
applicability in portable battery-powered drawn arc stud welding
systems. Nickel cadmium (NiCd) batteries may lose their charge
rapidly when not in use. NiCd batteries may also need to be
completely discharged/charged to prevent an effect known as the
memory effect, wherein NiCd batteries gradually lose their maximum
charge capacity if not fully discharged before recharging. This
effect only increases over time. Finally, NiCd batteries contain
toxic cadmium which, like lead acid batteries, create additional
hazards for environmentally appropriate disposal. (Battery type
characteristics information source:
http://batteryuniversity.com/learn/article/secondary_batteries).
[0009] Nickel metal hydride (NiMH) batteries may lose their charge
even more than NiCd batteries when not in use. NiMH batteries also
have a shorter cycle life (total number of charge/discharge cycles
lifetime) when compared to NiCd batteries. Finally, NiMH batteries
require double the recharging time of NiCd batteries.
[0010] Other lithium ion battery chemistries, including lithium
cobalt oxide (LiCoO.sub.2), lithium manganese oxide
(LiMn.sub.2O.sub.4), and lithium nickel manganese cobalt oxide
(LiNiMnCoO.sub.2, or "NMC") may be vulnerable to thermal runaway
from overcurrent and/or overheating, that could result in fires or
other hazardous situations. Finally, cobalt is a toxic metal, like
lead and cadmium, creating additional hazards for environmentally
appropriate disposal.
[0011] In view of the foregoing, there remains a need for a low
cost, portable, drawn arc stud welding system.
SUMMARY OF THE DISCLOSURE
[0012] The subject disclosure is directed to a portable battery
powered drawn arc stud welding system with an LFP battery and a
stud weld battery control system provides these benefits.
Specifically, a portable drawn arc stud welder apparatus with a
lithium ferrophosphate (LFP) battery and stud weld battery control
system (SWBCS) is provided for welding a stud onto a workpiece. A
portable drawn arc stud welder apparatus includes a housing, an LFP
battery disposed in the housing, a plurality of LFP battery cells,
a weld stud gun configured to hold a stud and electrically
connected to the LFP battery for receiving energy from the LFP
battery to pass an electric current through the stud and the
workpiece to form a weldment. The SWBCS is disposed in the housing
and electrically connected to the LFP battery of the portable drawn
arc stud welder apparatus. The SWBCS includes a computer (e.g.,
digital controller), a memory, and instructions therein to
implement control and monitoring of the operation of the portable
drawn arc stud welder apparatus, as will be described below.
[0013] A portable drawn arc stud welder apparatus with an LFP
battery and stud weld battery control system (SWBCS) is provided
for welding a stud onto a workpiece. The portable drawn arc stud
welder may include a housing, a lithium ferrophosphate (LFP)
battery that may disposed in the housing and may include a
plurality of LFP battery cells, a weld stud gun configured to hold
a stud electrically connected to the LFP battery for receiving
energy from the LFP battery to pass an electric current through the
stud and the workpiece to form a weldment, a stud weld battery
control system (SWBCS) disposed in the housing electrically
connected to the LFP battery of the portable drawn arc stud welder
apparatus. The SWBCS includes a computer, including a processor and
a memory, and instructions therein, to implement control and
monitoring of the operation of the portable drawn arc stud welder
apparatus. The SWBCS is configured to measure a temperature of the
LFP battery via the temperature sensors against a predetermined
temperature level. The SWBCS is configured to activate one or more
fans disposed in the housing if the measured temperature of the LFP
battery exceeds the predetermined temperature level, and/or based
on other control variables described herein. The SWBCS is
configured to deactivate the one or more fans when the measured
temperature drops below the predetermined temperature level, and/or
based on other control variables described herein.
[0014] The advantages of incorporating an LFP battery in a portable
drawn arc stud welder apparatus include at least that the portable
drawn arc stud welder apparatus delivers full strength stud welds
for structural applications. The portable drawn arc stud welder
apparatus meets the requirements of AWS D1.1, in a small,
lightweight package that a single user/operator can easily move.
The portable drawn arc stud welder apparatus is capable of welding
over one hundred (100) 1.27 cm (0.5 in) stud welds without the need
to recharge the LFP battery. The portable drawn arc stud welder
apparatus incorporating an LFP battery has a number of unique
battery performance attributes, including the capability to be
trickle (i.e., slow) charged continuously without damage to the LFP
battery, the trickle charge rate exceeds the weld discharge rate
(i.e., welding will not overtake the trickle charging late to
eventually discharge the LFP battery), no battery memory issues
necessitating full discharge before recharging, is intrinsically
safe from thermal runaway conditions, and creates no toxic or
hazardous waste at disposal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Other advantages of the present disclosure will be readily
appreciated, as the same becomes better understood by reference to
the following detailed description when considered in connection
with the accompanying drawings wherein:
[0016] FIG. 1 is a perspective side view of a portable drawn arc
stud welder according to an aspect of the disclosure, illustrating
at least a housing with a handle for allowing the portable drawn
arc stud welder to be easily carried by an operator/user;
[0017] FIG. 2 is a perspective view of a portable drawn arc stud
welder with a housing removed according to an aspect of the
disclosure, illustrating at least an LFP battery, a gun coil
capacitor, a stud welder battery control system (SWBCS) board, a
weld stud gun control board, an input control system board, a video
display board, and an LCD display;
[0018] FIG. 3 is a side view of the portable drawn arc stud welder
of FIG. 2;
[0019] FIG. 4 is the other side view of the portable drawn arc stud
welder of FIG. 2;
[0020] FIG. 5 is a top view of the portable drawn arc stud welder
of FIG. 2;
[0021] FIG. 6 is an exploded view of the portable drawn arc drawn
arc stud welder of FIG. 2;
[0022] FIG. 7 is a side view of the LFP battery of the portable
drawn arc stud welder of FIG. 2;
[0023] FIG. 8 is a schematic of the portable drawn arc stud welder
of FIG. 2;
[0024] FIGS. 9A-9F are flowcharts illustrating some embodiments of
control logic, including that within the SWBCS, of the portable
drawn arc stud welder of FIG. 2; and
[0025] FIG. 10 is an exemplary screenshot of an LCD user interface
of the portable drawn arc stud welder of FIG. 2.
DESCRIPTION OF THE EMBODIMENTS
[0026] Referring to the Figures, wherein like numerals indicate
corresponding parts throughout the several views, portable drawn
arc stud welder apparatus 20 is generally shown for welding a stud
onto a workpiece. A portable drawn arc stud welder apparatus 20
includes a housing 22 that generally has a cuboid shape and
includes a front wall 24, a back wall 26, a top wall 28, a bottom
wall 30, a first side wall 32 and a second side wall 34. As best
illustrated in FIGS. 1-6, the portable drawn arc stud welder
apparatus 20 includes a LFP battery 38, a SWBCS 42, a weld gun coil
capacitor 46, a weld current sensor 52, a weld gun control system
board 54, an input sensing control system board 62, a switching
transistor (e.g., an insulated gate bipolar transistor (IGBT)) 66,
a pair of weld terminals 68, an LCD user interface 80, at least a
pair of cooling fans 84, a charge port 86, a power switch 88, a
weld gun control connector 92, a handle 94, feet 96, and a LCD user
interface board 98.
[0027] FIGS. 2-6 illustrate an embodiment of portable drawn arc
stud welder apparatus 20 with housing 22 removed. First side wall
32 includes a pair of weld terminals 68. Weld terminals 68 include
a negative ("-") terminal 68A and a positive ("+") terminal 68B.
Also disposed on first side wall 32 is an LCD user interface 80
(see, for example, FIG. 11). LCD user interface 80 is a capacitive
touch screen with which an operator/user can operate portable drawn
arc stud welder apparatus 20 and adjust various characteristics of
the operation of portable drawn arc stud welder apparatus 20. First
side wall 32 also includes a power (on/off) switch 88. First side
wall 32 also includes a weld gun control connector 92. Weld gun
control connector 92 is configured to receive a weld gun 82 (as
shown in FIG. 9). First side wall 32 includes vents 102 that are
configured to facilitate air flow into and/or out of housing 22 and
are configured with fans 84.
[0028] A component shelf 100 is attached to front wall 24 and/or
back wall 26, and includes mounting locations for one or more
components of portable drawn arc stud welder drawn arc 20. In
embodiments, component shelf 100 includes (i.e., support) SWBCS 42.
SWBCS 42 is configured as one or more printed circuit boards (PCBs)
that includes one or more computer components (e.g., a processor,
memory, and/or systems on a chip). SWBCS 42 is connected via
component shelf 100 to one or more other components of portable
drawn arc stud welder apparatus 20, such as by wiring or other
electrical interfaces. Component shelf 100 includes weld gun coil
capacitor 46. Weld gun coil capacitor 46 is connected via component
shelf 100 to one or more other components of portable drawn arc
stud welder apparatus 20. Component shelf 100 includes weld current
sensor 52. Weld current sensor 52 is configured as one or more
printed circuit boards (PCBs) that include one or more computer
components (e.g., a processor, memory, and/or systems on a chip).
Weld current sensor 52 is connected via component shelf 100 to one
or more other components of portable drawn arc stud welder
apparatus 20, such as by wiring. Component shelf 100 includes weld
gun control system board 54. Weld gun control system board 54 is
configured as one or more printed circuit boards (PCBs) that
include one or more computer components (e.g., a processor, memory,
and/or systems on a chip). Weld gun control system board 54 is
connected via component shelf 100 to one or more other components
of portable drawn arc stud welder apparatus 20. Component shelf 100
includes input sensing control system board 62. Input sensing
control system board 62 is configured as one or more printed
circuit boards (PCBs) that include one or more computer components
(e.g., a processor, memory, and/or systems on a chip). Input
sensing control system board 62 is connected via component shelf
100 to one or more other components of portable drawn arc stud
welder apparatus 20. Component shelf 100 includes a switching
transistor (e.g., an integrated bipolar gate transistor (IGBT)) 66.
The IGBT 66 is configured as a switching transistor in order to
perform its needed role to regulate weld discharge current for
drawn arc stud welding, while additionally providing a means to
disable battery discharge current when required by SWBCS 42. The
IGBT 66 replaces by its integration with SWBCS 42, a large, bulky
relay (e.g., 900 .ANG. relay), or an expensive and/or large and
heavy transistor. The IGBT 66 is connected via component shelf 100
to one or more other components of portable drawn arc stud welder
apparatus 20. Component shelf 100 includes an LCD user interface
driver board 98 for the LCD user interface 80. LCD user interface
driver board 98 is configured as one or more printed circuit boards
(PCBs) that include one or more computer components (e.g., a
processor, memory, and/or systems on a chip). LCD user interface
driver board 98 is connected via component shelf 100 to one or more
other components of portable drawn arc stud welder apparatus
20.
[0029] A back wall 26 is also be connected to component shelf 100.
Back wall 26 includes a charge port 86 and vents 102. Charge port
86 is configured to receive a charging cord (not shown) and vents
102 is configured to engage one or more fans 84. Vents 102 that is
configured to facilitate air flow into and/or out of housing 22 via
one or more fans 84. First side wall 32 and second side wall 34 is
configured to engage a bottom wall 30. Bottom wall 30 includes
support for LFP battery 38, one or more fans 84, and one or more
feet 96.
[0030] Referring now to FIG. 7, an embodiment of LFP battery 38 of
portable drawn arc stud welder apparatus 20 is shown. LFP battery
38 includes a plurality of individual LFP battery cells 70. As
discussed herein, LFP battery cells 70 are arranged in arrays of
LFP cells 70, and the arrays of LFP cells 70 are combined (i.e.,
physically and/or electrically) to form LFP battery 38. In
embodiments, LFP battery cells 70 are connected (i.e., combined),
electrically in series. For example, a positive terminal of a first
LFP battery cell 70 is connected to a negative terminal of a second
LFP battery cell 70. This configuration may be repeated until, for
example and without limitation, sixteen (16) LFP battery cells 70
are joined in series. Additionally and alternatively, LFP battery
cells 70 are connected electrically in parallel.
[0031] In embodiments, LFP battery cells 70 are of a shape/size
such as 26 mm diameter.times.65 mm long. It should be understood
that other sizes and/or shapes of LFP battery cells 70 are
contemplated, and the characteristics of LFP battery cells 70
described herein are exemplary and not limiting. LFP battery cells
70 have the characteristics of LFP batteries as described herein,
such as a specific energy of 90-120 Wh/kg, a very low internal
resistance, a cycle life of 1000-2000 cycles. (based on 80% depth
of discharge), a charge time of 1-2 hr., a less than a 5% rate of
self-discharge/month (at room temperature), a nominal cell voltage
of 3.2-3.3 V, a charge cutoff voltage of 3.60 V/cell, a discharge
cutoff voltage of 2.50 V/cell.
[0032] Returning to FIG. 7, LFP battery cells 70 are shown arranged
in arrays (i.e., rows), of nine (9) LFP cells connected
electrically in parallel to each other by a cell buss bar 76. Cell
buss bar 76 is configured such that a first end of a cell buss bar
76 is connected to a first LFP battery cell 70 and subsequent
terminals of cell buss bar 76 (not shown) electrically connect LFP
battery cells 70 two through nine, forming a row of LFP battery
cells 70 as shown in FIG. 7. Disposed around LFP battery cells 70,
such as, but not limited to on top of and underneath LFP battery
cells 70 are insulation/thermal pads 74. Insulation/thermal pads 74
provide thermal conduction for cooling LFP battery cells 70.
[0033] Battery terminal buss bar 78 is shown electrically connected
to LFP battery cells 70. Battery terminal buss bar 78 includes a
terminal end portion 79 that is configured to distribute electrical
energy stored within LFP battery cells 70 and/or receive electrical
energy from charge port 86 via at least SWBCS 42.
[0034] LFP battery 38 includes heat sink walls 72 that are
configured to receive LFP battery cells 70, insulation/thermal pads
74, cell buss bars 76, battery terminal buss bars 78, and/or
temperature sensors 44. Heat sink walls 72 are constructed of a
material with a high thermal conductivity, such as aluminum, as
heat sink walls 72 function as an integral means to transfer heat
from LFP battery cells 70 into the forced air stream moving through
designed duct spaces on all sides of LFP battery 38, including at
least a central duct D through LFP battery 38, as shown in FIG. 7.
Heat sink walls 72 are configured with components (not shown) to
allow heat sink walls 72 to be securely attached to portable drawn
arc stud weld apparatus 20, such as bottom wall 30. Heat sink walls
72 include openings (i.e., apertures), to facilitate air flow from
fans 84 and/or heat dissipation from and around LFP battery cells
70. Heat sink walls 72 are configured to receive one or more
temperature sensors 44, such as, but not limited to, on the top and
bottom surfaces of heat sink walls 72 as shown in FIG. 7.
[0035] FIG. 8 is a schematic diagram of an embodiment of portable
drawn arc stud weld apparatus 20. Housing 22 includes LFP battery
38 including a plurality of LFP battery cells 70. Temperature
sensors 44 are disposed on LFP battery 38 as shown in FIG. 7. Both
LFP battery 38 and temperature sensors 44 are electrically
connected to SWBCS 42. In embodiments, SWBCS 42 is configured to
measure one or more temperatures of LFP battery 38 via temperature
sensors 44 against one or more predetermined temperature levels or
ranges stored in SWBCS 42 before, during, or after SWBCS 42
balances voltage level the plurality of LFP battery cells 70. SWBCS
42 is configured to selectively control one or more fans 84
disposed in housing 22 if the measured temperature of LFP battery
38 exceeds the predetermined temperature level or range stored in
SWBCS 42, and/or in response to other control variables described
herein. SWBCS 42 is configured to selectively control one or more
fans 84 via fan control module 106 when the measured temperature
drops below the predetermined temperature level or range stored in
SWBCS 42, and/or in response to other control variables described
herein.
[0036] LFP battery 38 is charged via charge port 86 disposed on
housing 22. Charge port 86 is electrically connected to SWBCS 42.
SWBCS 42 includes charge current sensor 50 to monitor, measure,
and/or regulate the current provided to LFP battery cells 70 of LFP
battery 38. A charge relay 104 is included in the LFP battery 38
charge circuit. Charge relay 104 is activated by SWBCS 42 during a
charge cycle, such as when SWBCS 42 determines via thermal sensing
module 108 and/or temperature sensors 44 that the measured
temperatures of LFP battery 38 are above a predetermined
temperature level stored in SWBCS 42. Additionally and
alternatively, charge relay 104 is activated by SWBCS 42 during a
charge cycle, such as when SWBCS 42 determines, via cell sensing
and balancing module 110, that the charge level of LFP battery
cells 70 of LFP battery 38 is measured to be above a predetermined
charge level stored in SWBCS 42. It should be noted that SWBCS 42
can monitor, measure, and/or regulate LFP battery 38 whether or not
power switch 88 is turn on (i.e., activated by a user).
[0037] Power switch 88 is configured with a power enable module
112. Power enable module 112 is included within SWBCS 42 to
determine the position of power switch 88 disposed on housing 22.
For example, power enable module 112 provides a signal to SWBCS 42
as to the status of power switch 88. This signal is used by SWBCS
42 to determine whether portable drawn arc stud weld apparatus 20
is in an off state, a charge only state, a charge and weld state,
or a weld state.
[0038] SWBCS 42 is configured with cell sensing and balancing
module 110. Cell sensing and balancing module 110 includes current
and voltage measurement devices and/or applications to monitor,
measure and/or regulate the levels of voltage and current of LFP
battery cells 70 of LFP battery 38. In embodiments, cell sensing
and balancing module 110 performs battery balancing on LFP battery
cells 70. Battery balancing includes determining the voltage level
of each LFP battery cell 70, comparing the determined voltages, and
adjusting the voltages according to predetermined voltages stored
in SWBCS 42. For example, a predetermined voltage for LFP battery
cells 70 may be 3.0 V. A measurement of LFP battery cells 70 by
SWBCS 42 determines that some LFP battery cells 70 are above 3.0 V,
some are below 3.0 V, and some are at 3.0 V. In embodiments, cell
sensing and balancing module 110 of SWBCS 42 discharges energy from
LFP battery cells 70 that are over 3.0 V to balance them with LFP
battery cells 70 that are below 3.0 V. In embodiments, cell sensing
and balancing module and/or SWBCS 42 displays one or more messages
on LCD user interface 80 for the operator/user, describing the
status of LFP battery cells 70 of LFP battery 38.
[0039] SWBCS 42 also includes a power supply 58 configured as a
plurality of DC/DC converters linked together, or "daisy-chained"
to a single DC/DC converter, the single DC/DC converter having a
larger capacity than the plurality of DC/DC converters. The single
DC/DC converter is configured with a broader operating range than
the plurality of DC/DC converters to process the varying voltage
from battery terminal buss bars 78 of LFP battery 38. Additionally,
the single DC/DC converter is equipped with an enable input pin
(not shown) that is activated by operation of power switch 88
and/or power enable module 112. By using the single DC/DC converter
of power supply 58, the current through power switch 88 is kept at
a lower level for operator/user safety and/or for automatic
activation by charging using charge port 86 or other peer welders
of the same type as portable drawn arc stud welder 20. Power supply
58 also is connected to a weld power switching power supply 60.
Weld power switching power supply 60 is connected to IGBT 66, part
of weld discharge circuit 114.
[0040] SWBCS 42 also includes a boost charge module 48 connected to
weld gun coil capacitor 46, weld gun control system board 54,
and/or weld gun 82. Boost charge module 48 is configured, through
SWBCS 42, to provide the current to charge weld gun coil capacitor
42 up with energy adequate to supply the solenoid of weld gun 82
for a stud weld.
[0041] SWBCS 42 is connected to input sensing control system board
62 that is also connected to weld current sensor 52, weld gun
control system board 54, LCD user interface 80, and weld discharge
circuit 114.
[0042] Weld discharge circuit 114 of portable drawn arc stud welder
20 includes a weld current sensor 52, a capacitor 56, weld choke
64, an IGBT 66, and weld terminals 68. Weld current sensor 52 is
configured as a Hall Effect transducer, with high frequency
response characteristics to detect high speed pulses that enable
SWBCS 42 to rapidly respond to overcurrent conditions, for example.
Weld current sensor 52 is configured to isolate SWBCS 42 from the
welding circuit (i.e., weld discharge circuit 114). Weld current
sensor 52 is configured as a Hall Effect transducer that also
provides a protective barrier preventing electrical noise from
interfering with SWBCS 42.
[0043] Referring to FIG. 9A, a flowchart details the operation of
SWBCS 42 and its programming. As described herein, SWBCS 42 is
implemented in a computer including at least a processor and a
memory. Non-limiting examples of a computer are a system-on-a-chip
and a digital controller.
[0044] After initialization, SWBCS 42 performs a number of system
level tasks. These system level tasks of SWBCS 42 are executed
simultaneously, linearly, or in a combination thereof. In
embodiments, some system level tasks are not executed, depending at
least upon the operational status of welder 20 and/or SWBCS 42.
[0045] In FIG. 9B, the first of a number of a system level tasks
that are executed by SWBCS 42. The first task is Measure Battery
Voltage. SWBCS 42 measures the voltage of LFP battery 38. The
measurement of the voltage of LFP battery 38 includes multiple
sampling averaged over time for each LFP battery cell 70 of LFP
battery 38. If the voltage of LFP battery 38 is below a
predetermined threshold (such as programmed into control system
42), a low LFP battery voltage signal is produced and is displayed
on LCD user interface 80. If the voltage of LFP battery 38 is at a
predetermined threshold, an OK LFP battery voltage signal is
produced and is displayed on LCD user interface 80.
[0046] As further described in FIG. 9E, system level task Measure
Battery Voltage involves several state of charge (SOC)
detections/reactions by at least SWBCS 42 and/or other components
of welder 20. When the rate of change of a measured LFP battery 38
voltage from a sequence of consecutive welds exceeds a
predetermined level, a Battery Low error is generated. Or, if the
difference between the weld current setpoint and the actual weld
current exceeds a predetermined value, and the measured LFP battery
38 voltage is below a predetermined voltage level, a "Battery Low"
error message is generated at least by SWBCS 42, and is displayed
on LCD user interface 80. Additionally and/or alternatively, SWBCS
42 measures the voltage of LFP battery 38 and determines a state of
charge (SOC) of LFP battery 38 that is displayed on LCD user
interface 80. Additionally and/or alternatively, SWBCS 42 measures
charging current for LFP battery 38 and/or determines if the
measured charging current of LFP battery 38 is above a
predetermined charging current level. The measured charging current
(and/or other relevant data) of LFP battery 38 is displayed on LCD
user interface 80.
[0047] Another system level task is Measure Individual Cell
Voltage. SWBCS 42 is configured to measure the voltage of each bank
of parallel-connected LFP battery cells 70 of LFP battery 38. After
obtaining a measurement of the voltage of each bank of
parallel-connected LFP battery cells 70 of LFP battery 38, SWBCS 42
compares the individual banks of LFP battery cells 70 to each other
to determine if balancing is required. Battery balancing involves
transferring energy from banks of LFP battery cells 70 of LFP
battery 38 until the voltage level of all of the banks of LFP
battery cells 70 of LFP battery 38 have a voltage level that is
within a predetermined narrow range, for example. SWBCS 42 is
configured to continue balancing while completing other system
level tasks.
[0048] If battery balancing is required (i.e., the voltage of the
cells of LFP battery 38 is unbalanced and/or unequal), SWBCS 42 is
configured to transfer energy from cells until the LFP battery
cells 70 of LFP battery 38 are balanced (i.e., are within a
predetermined balance range). If battery balancing is not required
(i.e., the cells of LFP battery 38 are balanced), SWBCS 42 will not
perform this task.
[0049] Another system level task of SWBCS 42 is Measure Battery
Cell Thermal Sensors. SWBCS 42 uses temperature sensors 44 to
measure temperatures of LFP battery 38. Temperature sensors 44 may
be, for example, thermocouples, or negative temperature coefficient
(NTC) thermistors configured to measure temperature using
electrical energy. Temperature sensors 44 are disposed at least
about LFP battery 38 of welder 20. Temperature sensors 44 are also
disposed about housing 22, for example. As described herein,
temperature sensors 44 are disposed within LFP battery 38, such as
around or near one or more cells of LFP 38.
[0050] SWBCS 42, using temperature sensors 44, receives temperature
measurements (i.e., readings), of temperatures at the various
locations of temperature sensors 44, including, but not limited to,
LFP battery 38. Upon receiving the temperature measurements from
temperature sensors 44, SWBCS 42 determines, using application
software, for example, whether LFP battery 38 (or other components
of welder 20) require cooling (i.e., a reduction in temperature or
whether the welding process should be ended).
[0051] If SWBCS 42, through the data obtained from temperature
sensors 44 determines that the temperature measurements from
temperature sensors 44 are within a predetermined temperature range
(i.e., temperature "OK"), then SWBCS 42 turns off (or selectively
controls) one or more fans 84 of welder 20. In embodiments, SWBCS
42, upon startup, activates fans 84 automatically, before
performing the system level task Measure Battery Cell Thermal
Sensors. This activation occurs to lower the temperature of LFP
battery 38 and/or other components of welder 20, such as a
situation where welder 20 is in a hot environment (e.g., closed
vehicle on a hot day, sun soak, or as a pre-emptive action in
response to a high weld rate before sensing a high temperature via
temperature sensors 44).
[0052] If SWBCS 42, through the data obtained from temperature
sensors 44 determines that the temperature measurements from
temperature sensors 44 are not within a predetermined temperature
range (i.e., temperature "too high"), SWBCS 42 activates one or
more fans 84 of welder 20.
[0053] SWBCS 42 continues to obtain data from temperature sensors
44 for a predetermined time period, such as during which time
welder 20 is powered on, or while welder 20 is powered on and
operating in welding mode (i.e., discharging current to a
workpiece, or while charging).
[0054] As further described in FIG. 9D, system level task Measure
Battery Cell Thermal Sensors involves thermal
measurements/determinations by at least SWBCS 42 and/or other
components of welder 20.
[0055] As described herein, welder 20 includes one or more fans 84.
Fans 84 are configured to operate at one or more speeds and/or to
operate at variable speeds (e.g., selectively control). For example
and without limitation, a first fan 84 is configured to operate at
a "low" and a "high" speed, with the speed (i.e., rpm), of the
first fan 84 at a low speed may be approximately 500 rpm, while the
high speed may be approximately 1000 rpm. A second fan 84 is
configured to operate at variable speeds throughout the operating
range of the second fan 84. Additional fans 84 may be included in
welder 20 and may be configured to operate with vents 102 and/or
other air flow management devices (not shown).
[0056] A first thermal measurement/determination includes a
transition of fans 84 from "off" to a first speed (e.g., "low"). If
either a measured weld frequency exceeds a predetermined weld
frequency level, or a measured battery temperature rate of change
exceeds a predetermined temperature rate of change level, or if the
measured average power from LFP battery 38 exceeds a predetermined
average power level and if the measured temperature level of LFP
battery 38 exceeds a predetermined level, fans 84 are configured
from "off" to a first speed. In alternative embodiments, a
configuration from "off" is to a variable speed, that may be
proportional (or have another relationship) to the amount(s)
exceeding the respective predetermined level(s).
[0057] A second thermal measurement/determination includes a
transition of fans 84 from a first ("low") speed to a second
("high") speed. If either a measured weld frequency exceeds a
predetermined weld frequency level, or a measured battery
temperature rate of change exceeds a predetermined temperature rate
of change level, or if the measured average power from LFP battery
38 exceeds a predetermined average power level and the measured
temperature of LFP battery 38 exceeds a predetermined temperature
of LFP battery 38, fans 84 are configured from the first "low"
speed to the second "high" speed. In alternative embodiments, a
configuration from a first variable speed to a second variable
speed, each of which may be proportional (or have another
relationship) to the amount(s) exceeding the respective
predetermined level(s).
[0058] A third thermal measurement/determination includes a
transition of fans 84 from a first ("high") speed to a second
("low") speed. If a measured weld frequency is below a
predetermined weld frequency level, and a measured battery
temperature rate of change is below a predetermined temperature
rate of change level, and if the measured average power from LFP
battery 38 is below a predetermined average power level and the
measured temperature of LFP battery 38 is below a predetermined
temperature of LFP battery 38, fans 84 are configured from the
first "high" speed to the second "low" speed. In alternative
embodiments, a configuration from a first variable speed to a
second variable speed, each of which may be proportional (or have
another relationship) to the amount(s) below the respective
predetermined level(s).
[0059] A fourth thermal measurement/determination may include a
transition of fans 84 from a "low" speed to off (i.e., inactive).
If a measured weld frequency is below a predetermined weld
frequency level, and a measured battery temperature rate of change
is below a predetermined temperature rate of change level, and if
the measured average power from LFP battery 38 is below a
predetermined average power level and the measured temperature of
LFP battery 38 is below a predetermined temperature of LFP battery
38, fans 84 are configured from the "low" speed to off. In
alternative embodiments, a configuration from a variable speed to
off, which may be proportional (or have another relationship) to
the amount(s) below the respective predetermined level(s).
[0060] Another system level task is Measure Gun Capacitor. SWBCS 42
determines whether weld gun coil capacitor 46 is fully charged. If
SWBCS 42 determines that weld gun coil capacitor 46 is not fully
charged, SWBCS 42 activates boost charge module 48 to fully charge
weld gun coil capacitor 46 to a predetermined voltage level (a
predetermined level determined by welder 20). When weld gun coil
capacitor 46 is fully charged, as determined by SWBCS 42, SWBCS 42
moves to the next system level task, Thermal Overload Sensor Input.
Similarly, if SWBCS 42 determines that weld gun coil capacitor 46
is already fully charged (i.e., no further charge is needed based
on a predetermined level).
[0061] Another system level task is Power Saving. Power Saving
includes a determination by SWBCS 42 (and/or other components of
welder 20) if timer 134 is initially activated (i.e., welder 20 is
turned "on") or if an encoder of welder 20 is turned, or if LCD
user interface 80 is activated (i.e., touched by an operator/user),
then the condition of LCD user interface 80 is configured from a
power saving condition (i.e., dimmed), to a full power condition
(i.e., full brightness).
[0062] A second Power Saving task includes a determination by SWBCS
42 (and/or other components of welder 20) if a measured state of
charge (SOC) is less than a predetermined SOC level or if a
measured weld frequency decreases below a predetermined weld
frequency level or if an encoder of welder 20 is determined by
SWBCS 42 (and/or other components of welder 20) to have been
inactive for a predetermined time period or if LCD user interface
80 is determined by SWBCS 42 (and/or other components of welder 20)
to have been inactive (i.e., not touched by an operator/user) for a
predetermined time period and if welder 20 has been configured (by
the operator/user and/or SWBCS 42) to a power saving configuration
then the condition of LCD user interface 80 is configured from a
full power condition (i.e., full brightness) to a power saving
condition (i.e., dimmed).
[0063] A third Power Saving task includes SWBCS 42 (and/or other
components of welder 20) configuring LCD user interface 80 to
display, for an operator/user, a state of charge (SOC) icon (e.g.,
a stylized battery), and/or provide an estimate (based at least in
part on a determination by SWBCS 42) of a number of welds at the
operator/user's set point. The operator/user may use this
information to determine how to utilize the remaining charge of LFP
battery 38 (e.g., perform more welds at a lower power setting).
[0064] A fourth Power Saving task includes a determination by SWBCS
42 (and/or other components of welder 20) if a measured weld
frequency is below a predetermined weld frequency threshold and if
welder 20 is configured to automatically turn off (i.e., auto power
off), and a measured time since the last weld operation exceeds a
predetermined time period and an encoder of welder 20 has not been
activated and LCD user interface 80 has not been touched (i.e.,
touch screen time-out has not expired) or the measured state of
charge (SOC) of LFP battery 38 is below a predetermined SOC level,
then welder 20 shuts down automatically. In the situation of the
measured SOC of LFP battery 38 resulting in welder 20 shutdown, the
shutdown is for protection of LFP battery 38 (i.e., prevent damage
to LFP battery 38). In the other situations described in the fourth
Power Saving task, the shutdown is for convenience of the
operator/user (i.e., temporarily leaving welder 20 but intending to
return and resume welding).
[0065] In system level task Thermal Overload Sensor Input, SWBCS 42
determines the status (i.e., operating condition), of temperature
sensors 44. As discussed herein, monitoring the temperature of LFP
battery 38 is an important factor in the operation of welder 20. As
a result, SWBCS 42 determines the status of each of temperature
sensors 44 monitoring LFP battery, as well as any other temperature
sensors 44 disposed in welder 20. SWBCS 42 determines the status of
temperature sensors 44 by measuring a return voltage or signal
provided by temperature sensors 44, for example. SWBCS 42, upon
determination of at least one error in temperature sensors 44
(i.e., thermal overload sensor input), deactivates welder 20 or
otherwise alter the operation of welder 20, such as to protect LFP
battery 38. If SWBCS 42 determines that there are no errors in
temperature sensors 44 (i.e., predetermined or expected voltages or
signals are returned).
[0066] In system level task Measure Battery Charge Current, SWBCS
42 may determine, using battery charge current sensor 50 and
voltage measuring circuitry, whether the current and voltage levels
are in predetermined current and voltage ranges. If, for example, a
bank of LFP battery cells 70 voltage is too low while charging,
SWBCS 42 may open charge relay 104 to break the charge path and end
the battery charging process and display an error message on LCD
user interface 80.
[0067] In system level task Contact Input, SWBCS 42 determines,
using weld gun 82, whether contact has been made by the stud held
by the weld gun 82 and with a workpiece, completing a circuit and
providing the conditions for a drawn arc weld process to occur. If
SWBCS 42 determines that contact has not been made by the stud held
by the weld gun 82 and with the workpiece, the system level tasks
are ended, and the drawn arc weld process does not occur. If SWBCS
42 determines that contact has been made by the stud held by the
weld gun 82 and with the workpiece, SWBCS 42 allows the weld
process to occur.
[0068] In system level task Gun Trigger Input, SWBCS 42 determines,
using weld gun control system board 54, whether the trigger of weld
gun 82 has been pressed (by an operator/user). If SWBCS 42
determines that the trigger of weld gun 82 has not been pressed,
the system level tasks are ended, and the drawn arc weld process
does not initiate. If SWBCS 42 determines that the trigger of weld
gun 82 has been pressed, SWBCS 42 then determines whether there are
errors present (e.g., temperature error, low battery charge, weld
gun coil short, etc.). If there are no errors present and workpiece
contact is made, SWBCS 42 allows the drawn arc weld process to
initiate, and after the weld routine executes and finishes the
system level tasks end. If there are errors present, the system
level tasks are ended, and the drawn arc weld process does not
initiate, and the system level tasks end.
[0069] Referring to FIG. 9C, the weld process of SWBCS 42 is
described. The first step is Enter Weld Process. The weld process
begins after an operator/user brings a stud into contact with a
workpiece, presses the trigger of weld gun 82, a solenoid of weld
gun 82 lifts the stud, stud draws an arc, and after a predetermined
arc time elapses, the solenoid of weld gun 82 is de-energized, and
the gun spring plunges the stud into the molten pool formed in the
workpiece.
[0070] The next step, Pause Cell Balancing and Charging, occurs as
a result of the initiation of the weld process. At this time, any
cell balancing (as described herein) by SWBCS 42 may be paused, or
halted. This pausing or halting allows for LFP battery 38 to
deliver weld current independently, without drawing current from
the charging system, or from the SWBCS.
[0071] The next step, Regulate Low Current (high gain) occurs as a
relatively low current, called the pilot current, is passed into
the short circuit by weld gun 82, and is maintained (i.e.,
regulated), by SWBCS 42 when the stud is lifted by a small distance
from the workpiece, in the next step.
[0072] The Lift Stud (energize gun solenoid) step occurs once the
low current (pilot current) flow is established between the stud
and the workpiece. Weld gun 82 is energized, resulting in an arc
forming in the small distance between the stud and the workpiece.
SWBCS 42 determines whether an arc is formed or not, such as by
determining (i.e., monitoring), the flow of weld discharge current
and the arc weld voltage. If SWBCS 42 determines that an arc has
been drawn by measuring arc voltage and weld current via weld
current sensor 52, the process continues to the next step.
[0073] In the next step, Regulate Setpoint Current (lower gain),
occurs after a pilot arc has been drawn. SWBCS 42 utilizes a timer
function that is set internally (i.e., a predetermined time) or by
an operator/user using LCD user interface 80 to set weld time. Weld
time is displayed on LCD user interface 80. SWBCS 42 thus controls
the length of time the weld arc is drawn (or present) between the
stud and the workpiece, and when the arc ends. SWBCS 42, for
example, controls a length of weld arc time as short as 100
milliseconds. Once SWBCS 42 determines that the programmed time has
elapsed, the process moves to the next step, Drop Stud (de-energize
gun solenoid).
[0074] In the Drop Stud (de-energize gun solenoid) step, another
timer function is used by SWBCS 42 to determine the length of time
that current is maintained after the stud is plunged into the
workpiece. The time that current flows through the stud into the
workpiece is monitored by SWBCS 42. Once that time has expired,
SWBCS 42 stops current flow through the stud to the workpiece and a
weld is formed, joining the stud and the workpiece.
[0075] At this point SWBCS 42 determines whether there is contact
between the gun chuck and the welded stud based on the contact
detect functions on the input sensing control system board 62.
SWBCS 42 continues to determine if the chuck of weld gun 82 is
still in contact with the welded stud. If weld gun 82 is no longer
in contact with the welded stud, SWBCS 42 then determines if the
trigger of weld gun 82 has been released (such as by an
operator/user). If the trigger of weld gun 82 has been released,
the weld process of SWBCS 42 ends.
[0076] FIG. 10 illustrates an exemplary visual readout of LCD user
interface 80. LCD user interface 80 includes a plurality of touch
screens, one of which is illustrated in FIG. 10. The information
displayed on LCD user interface 80 is at least provided to LCD user
interface board 98 for display on LCD user interface 80 by SWBCS
42, though other components of welder 20 also utilize LCD user
interface 80 and/or LCD user interface board 98 alone or in
conjunction with SWBCS 42. It is also contemplated that LCD user
interface 80 includes supplemental controls disposed about welder
20 that are used in conjunction with or solely to interact with LCD
user interface 80. In the exemplary touch screen shown in FIG. 10,
an adjust weld current control 120 is provided. By pressing on
adjust weld current control 120, an operator/user raises or lowers
the current used in the next weld and shown on LCD user interface
80 as current level 132.
[0077] A system setting control 122 is provided on LCD user
interface 80. In this embodiment, system setting control 122 is
represented by a geared wheel, though other icons may be used. By
pressing on system setting control 122, an operator/user causes one
or more additional touch screens to appear on LCD user interface
80. These additional screens include, for example, a total weld
counter which tracks the total number of weld processes of welder
20; a user weld counter which tracks the total number of weld
processes by a particular operator/user and includes a reset option
(such as to track a number of welds by an operator/user for a
particular task); a factory default option, which returns welder 20
to factory default settings; a service settings password entry
option, which is used by an authorized service technician to
perform service and/or maintenance on welder 20; and a display
voltage option, which allows the operator/user to toggle between
displaying the weld voltage on LCD user interface 80.
[0078] An error/notification control 124 is provided on LCD user
interface 80. In this embodiment, error/notification control 124 is
represented by a bell, though other icons may be used. By pressing
on error/notification control 124, an operator/user causes one or
more additional touch screens to appear on LCD user interface 80.
These additional screens include, for example, details of any error
messages or other notifications regarding the operation of welder
20 and provide the operator/user with additional information or
requests for the operator/user to respond.
[0079] A lock/unlock control 128 is provided on LCD user interface
80. In this embodiment, lock/unlock control 128 is represented by
padlock, though other icons may be used. By pressing on lock/unlock
control 128 an operator/user causes one or more additional touch
screens to appear on LCD user interface 80. These additional
screens include, for example, a lock/unlock toggle control that if
activated by the operator/user, to lock the LCD user interface 80
to prevent any undesired changes to settings made by the
operator/user, such as due to an accidental contact of LCD user
interface 80 by the operator/user during a welding process.
[0080] A preset control 130 is provided on LCD user interface 80.
In this embodiment, preset control 130 is represented by a three by
three cube, though other icons may be used. By pressing on preset
control 130, an operator/user causes one or more additional touch
screens to appear on LCD user interface 80. These additional
screens include, for example, a preset control screen that includes
controls for the operator/user to store and/or recall presets
stored in welder 20. For example, weld settings include, but are
not limited to, weld time, weld current, lift height, and plunge
depth that may be saved and/or recalled by the operator/user.
[0081] An adjust weld time control 144 is provided on LCD user
interface 80. By pressing on adjust weld time control 144, an
operator/user raises or lowers the weld time for the next weld and
shown on LCD user interface 80 as timer 134.
[0082] A battery charge level 136 is provided on LCD user interface
80. In this embodiment, battery charge level 136 is represented by
a stylized battery, though other icons may be used. Battery charge
level 136 is displayed to the operator/user by selectively
displaying the interior of the stylized battery to represent the
battery charge level (e.g., an interior that is half-full
represents a half level battery charge).
[0083] A weld results control 138 is provided on LCD user interface
80. In this embodiment, weld results control 138 is represented by
graphs, though other icons may be used. By pressing on weld results
control 138, an operator/user causes one or more additional touch
screens to appear on LCD user interface 80. These additional
screens include, for example, a screen detailing the details of the
previous weld for the operator/user to review.
[0084] A weld process monitor 140 is provided on LCD user interface
80. In this embodiment, weld process monitor 140 is represented by
graphs, though other icons may be used. By pressing on weld process
monitor 140, an operator/user causes one or more additional touch
screens to appear on LCD user interface 80. These additional
screens include, for example, a chart providing for the
operator/user a view of the weld waveform as the result of the
previous weld. The chart may include an overlay of the weld current
and the weld gun motion.
[0085] A weld gun status indicator 142 is provided on LCD user
interface 80. In this embodiment, weld gun status indicator 142
displays contact status (with the workpiece), gun trigger status,
and/or coil status, by illuminating their respective sections on
the graphic indicator.
[0086] A Stud Expert control 143 is provided on LCD user interface
80. By pressing on the Stud Expert control 143, an operator/user
causes one or more additional touch screens to appear on LCD user
interface 80. These additional screens include, for example, a
screen which allows the operator/user to input a stud diameter, and
to receive the correct settings for weld time and weld current
corresponding to the input stud diameter.
[0087] Obviously, many modifications and variations of the present
disclosure are possible in light of the above teachings and may be
practiced otherwise than as specifically described while within the
scope of the appended claims. These antecedent recitations should
be interpreted to cover any combination in which the inventive
novelty exercises its utility.
* * * * *
References