FIELD OF THE INVENTION
The present invention generally relates to a method for battery testing. More particularly, the present invention relates to a system for performing high rate discharge capacity test of batteries and a method for battery testing.
More particularly, the present invention relates to a system for performing high rate discharge capacity test of batteries and a method for battery testing.
BACKGROUND OF THE INVENTION
Storage batteries, such as lead acid storage batteries are long-known in the art. However, accurate testing of operational behaviour of such storage batteries during production, is quite difficult. There has been a long history of attempts to accurately test in the production line, the condition of storage batteries for starting and other high-rate applications.
Patent Publication No.W02004023580 discloses a method and apparatus for rapidly and safely estimating the high-rate load test voltage of a storage battery utilizing open-circuit voltage, temperature and a dynamic parameter such as conductance or resistance. An output indicative of the condition of the battery is provided as a function of the estimated load test voltage of the battery compared to industry standards without the necessity to charge the battery or discharge the battery with high-rate loads using bulky testing equipment.
Publication No. JP2002131402 relates to a tester for secondary battery which comprises a discharging means for giving a constant current load to a battery to be tested, a voltage measurement means for measuring the voltage during discharging of the battery to be tested, and a calculation means for estimating the life of the battery based on a voltage value difference measured at least at two points after elapsing of a specific time from the discharge initiation of the battery including discharge characteristic values set in advance.
Publication No. W09845722 discloses a multiple battery tester having a tray loaded with a set of batteries. The tray is placed in a receptacle and the terminals located at both ends move vertically to clamp a specific battery. The contacts bear on the battery, establishing a current flow path. This loop connects in charge/discharge system for testing. Test routines can be varied and data is recorded over time.
Publication No. GB1342110 relates to maintaining the discharge current of a battery constant by a servo system which includes a motor for adjusting a rheostat in the discharge current path. Signals respectively proportional to the desired and actual currents are compared in a differential amplifier and if their difference is too high, one or other of two zener diodes breaks down to energize a corresponding relay which in turn supplies power to the motor to drive it in the appropriate direction.
Publication No. TW224683 relates to a battery capacity tester including a test current source circuit, a microprocessor, a battery resistance table memory, a voltage measuring unit, and a display unit. The test current source circuit is connected at both ends of the battery to be tested. A battery resistance table for at least one type of battery is stored in the battery resistance table memory. In the battery resistance table, each type of battery has a battery resistance and each battery resistance has a corresponding battery capacity. In accordance with the obtained battery open-circuit voltage, load-end voltage, and test current, the microprocessor calculates the battery resistance of the battery before, based on the battery resistance, searching from the battery resistance table stored in the battery resistance table memory for the battery capacity corresponding with the battery resistance.
Publication No. CN2272141 discloses a computerized tester of battery parameters. The tester comprises a microprocessor, an A/D switching circuit, a plurality of inspection circuits, a sampling circuit, a battery discharging control circuit, a hardware watchdog circuit, an RAM power-down protecting circuit, a display circuit, and a keyboard. The tester utilizes a control data processing system which takes the single-chip microprocessor as the center to measure and monitor a plurality of parameters, such as voltage, electric current, and environment temperature of a battery pack to be monitored to achieve the computerization of measurement and monitoring of battery parameters.
Publication No. US 20060186890 teaches a method and an equipment for measuring internal impedance of a secondary battery which supplies loads with electric power, and a method for determining deterioration in charging capacity of the secondary battery.
Publication No. US 20090001934 describes a battery testing apparatus which includes a charge circuit, a discharge circuit, a computer, and a control circuit. The charge circuit is coupled to a direct current (DC) adapter, the DC adapter charges a battery through the charge circuit. The discharge circuit is coupled to the battery and configured to discharge the battery. The computer records charge/discharge time and charge/ discharge cycles of the battery and calculates capacity and cycle life of the battery according to the time and cycles of charge and discharge. The control circuit has an input terminal coupled to the computer, and a plurality of output terminals respectively coupled to the charge circuit and the discharge circuit. The control circuit controls the charge and discharge circuits charging and discharging the battery.
Publication No. CN 201122178 teaches an all-purpose tester device for a storage battery. The tester allows determining storage battery constant-current discharge including cell capacity judgment. The device comprises a discharge unit realizing the constant-current discharge, a monitoring unit providing comparison current for the discharge unit and monitoring battery capacity, and a data processing unit processing the data and generating a corresponding graph.

The device realizes the constant-current discharge through an inter-reaction of the discharge unit, the monitoring unit and the data processing unit, and can measure the capacity of a storage battery in real time and prevent the storage battery form over discharge.
US Patent No. 7,081,755 discloses a method and an apparatus for predicting as to how a vehicle battery would perform when used to start a vehicle. According to the cited disclosure, discharging voltage / current of the battery is predicted as a function of a battery dynamic parameter, an open circuit voltage of the battery, a battery temperature and a fixed current/voltage value at which the battery is to be discharged. This discharge voltage/current value is compared to a minimum starting voltage/current required to start the vehicle in which the battery is employed and an output indicative of a starting capability of the battery is provided.
Reference may be made to a non-patent literature entitle 'Production line high rate discharge testing for battery manufacturing' by Powercon Equipment (India) Pvt. Ltd. The article proposes a rapid, reliable high rate discharge (HRD) test, to meet simultaneous requirements of reliability and productivity. The system is fully automatic and can be optionally integrated with peripheral devices such as Barcode printers. The system is supplied as two parts - an 'Electronic' High Rate Discharge Tester, with its own electronic load, and a 'Mechanical' Conveyor Assembly, with its Discharge Probe Head, Battery Clamping arrangement and
Bypass Conveyor for rejected Batteries. The two units are integrated with each other via a Progrannmabie Logic Controller which controls the operation of the Equipment in fully automatic mode. On sensing the conditions that a battery is due to lead into the PLT, the Equipment automatically positions the probe head on to the Battery Terminals, performs OCV and HRD tests, and conveys the Tested Battery to the Accept or Reject outlets of the Machine depending on the result of the Test. Acceptance criteria can be set thorough the Program, and the test Results are stored for future reference. With the optional Bar code system, the PLT can perform automatic Program selection through an unattended Bar code scanner and store the Test Data against the Battery Serial Number with 100% traceability. It is configurable as per the layout of specific Production Lines. Test head is supplied to suit all standard battery top terminal arrangements, and (optionally) for side terminal arrangement. Height of the conveyor is adjustable to match the height of the feeding and exit conveyor in your Plant. It is capable of fully automatic as well as manual operation. The bar code integrated PLT can be supplied as an option.
Thus, the prior art battery testers determine whether a battery falls in a "good" or "bad" category. However, such general categorizations or test results are insufficient for predicting whether the battery is capable of providing sufficient voltage and/or current to an utility in which the battery is employed. The manufacturer of high performance batteries are facing continuously escalating demands on battery life and performance, it is important to make sure that every
battery produced in the factory meets stringent quality standards. Also the disadvantages of the prior art in calibration of IR and voltage calibration, can be eliminated.
Therefore, there exists a need for a high productivity, and reliable test process which can be integrated into the production line and proves to be cost effective.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to propose a system for performing high rate discharge capacity test of batteries which eliminates the disadvantages of prior art.
Another object of the present invention is to propose a method for battery testing in which internal impedance of a secondary battery is measured without affecting polarization in the measurement values.
A still another object of the present invention is to propose a system for performing high rate discharge capacity test of batteries, which is enabled to test batteries having variable selection of dischargeable current value.
Yet another object of the present invention is to propose a system for performing high rate discharge capacity test of batteries, which indicates discharging voltage of the battery in a graphical form.
Another object of the present invention is to propose a system for performing high rate discharge capacity test of batteries, which generates barcodes during battery testing for accepted batteries only.
Yet another object of the present invention is to propose a method for battery testing which is designed to test batteries conforming to battery standards and performs discharge capacity tests of batteries.
A further object of the present invention is to propose a system for performing high rate discharge capacity test of batteries which is cost effective and easy to operate.
A still further object of the present invention is to propose a method for battery testing which can be monitored and controlled remotely and/or locally.
Yet further object of present invention is to propose a system for performing high rate discharge capacity test of batteries which records and stores the testing results and generates reports at remote or local location.
SUMMARY OF THE INVENTION
Accordingly, there is provided a system for performing high rate discharge capacity test of batteries comprising a load assembly, a control unit, a mechanical assembly, and a communication means, wherein the load assembly constitutes a transistor assembly and provides discharge path to the system and consists of N transistors, and X-power transistors, the N-translstors connected In parallel configuration to carry (NxY) Amp current, wherein said each of said N-transistor carries current of Y Amp, wherein said X power transistors connected in parallel and Including at least one driver transistor, and wherein said control unit controls the discharge current through the transistor assembly. The invention further provides a method for battery testing. The system is designed to test batteries conforming to battery standards and performs discharge capacity tests of batteries. The system Incorporates conservatively rated components for exceptional long-term reliability.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the Invention may admit to other equally effective embodiments.
Figure 1 shows a block diagram of a system for performing high rate discharge capacity test of batteries;
Figure 2 shows a plurality of proximity sensors according to the present invention;
Figure 3 shows a flow chart depicting the method according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference is made to figure 1 which shows a block diagram of the high rate discharge (HRD) system according to the present invention. The system comprises a load assembly 1, a control unit 2, a mechanical assembly 3A & 3B and a communication means 4, one each voltage / current / IR meter 5A, 5B, 5C, and sensors I, II. The system is designed to test batteries conforming to battery standards and performs discharge capacity test of batteries.
Discharge operation of the HRD tester is implemented under constant current with forced air-cooled power transistors which allows selected of any battery type. Normally discharge rates constitute selectable test conditions which are displayed, and include open circuit voltage (OCV), discharge current and discharge voltage. In case of rejection during testing, the rejected batteries are separated to a separate conveyor.
The load assembly generally comprises a transistor assembly which provides discharge path to the system. It consists of N transistor assemblies connected in parallel configuration to carry (NxY) Amp current. Each transistor assembly carries current of Y Amp. It consists of X power transistors connected in parallel and at least one driver transistor assembly. Discharge current through the transistor assembly is controlled by the control section. A diode Dl or MOSFET with internal diode is provided in the transistor assembly to protect the transistor assembly in case of reverse connection of battery. The following is an example of the assembly.
Example 1: The transistor assembly consists of at least 42 transistor assemblies connected in parallel configuration to carry lOOOAmps current. Each transistor assembly carries current of 25A. It consists of at least eight power transistors connected in parallel and at least one driver transistor assembly. Discharge current through transistor assembly is controlled by control electronics A diode Dl is provided in the transistor assembly to protect the transistor assembly in case of reverse connection of battery.
The control unit consists of such as but not limited a microcontroller, a PLC, an ASIC, and FPGA or any such system with Digital / analog input, / Digital / analog output and potential free contact. It controls the complete system to test the battery. All conveyers, clamping, declamping, upper cylinder and stopper are controlled through the controller. All data measured by the system is transmitted
to the computer with the help of the controller. A touch screen display is provided on the front panel to enter and display data. In an embodiment, the associated data can be displayed. The digital and analogue inputs / outputs are variables and can be changed as per the user's requirements.
The machine comprises a main conveyor having an arrangement to transport the batteries which are under test to a test clamp assembly. The batteries are then transferred to a next production conveyor or to a reject conveyor depending upon the test-result (accept or reject). The conveyor is driven by the motor which is connected to a reduction gear box and further to a chain drive to achieve the required conveyor speed. Speed of the conveyor motor is controlled through a VFD. The clamping assembly has two leads which are connected directly to the output of the electronic discharger unit. The leads position is adjusted according to the battery size. The clamp moves down when the battery under test is sensed and then touches battery lead to make a rigid contact to carry the required discharge current. A plurality of cylinders for example, a top clamping cylinder, a stopper cylinder, a battery clamping cylinder 1, a rejection cylinder, a stopper cylinder 2 are provided with the system. A multiplicity of Proximity switches (as shown in figure 2) are provided in the system to sense the following:
a) Proximity sensor 1 senses the input battery entering
b) Proximity sensor 2 senses the battery is in position under the top clamping cylinder.
c) Proximity sensor 3 senses that the battery going out of the main conveyor or is in the right position for rejection cylinder to push it to the rejection conveyor.
d) Proximity sensor 4 senses the number of batteries in the rejection conveyor and senses the accumulation of batteries in rejection conveyor.
e) Reed switches are magnetic switches which are connected on every cylinder. These switches sense the position of the cylinder either home position or extended position.
The system has variable selection of current value at which battery will discharge. The voltage trends are represented in graphical form to show when the battery is discharging, Barcodes are generated for accepted batteries only. Daily count of accepted and rejected batteries during the test including a temperature graph is displayed. Reports are generated showing voltage, current, discharging current, delta T & V. Current Vs voltage graph is also displayed. The reports are printed in a printer 7. According to the present invention, calibration is also possible through error correction feature for parameter such as voltage, current & internal resistance. According to the present invention, calibration factor can be adjusted by the user after every 2-3 months Barcodes are generated after every battery is accepted in the test process.
Figure 3 shows a control flow chart according to the present invention. The system implementing the control process, is a mechanical system with digital input and output capability. All the generated signals from the sensors go to a control unit which inter alia provide feed back of the operational parameters of the system. It is possible to feed and display value of current, voltage and resistance on a touch screen as well as on the computer apparatus. The control unit communicates with the touch screen display on MODBUS communication and to the computer apparatus through Ethernet. The speed of the conveyer is adjusted through AC variable frequency drive. Mechanical adjuster helps in adjusting the width and height. Transistorized load discharges the battery upto (NxY)A of current.
As the battery moves on the conveyor, sensor I allows the battery to move for testing upon sensing that there is no battery under test. Sensor II informs the control unit that the battery is at the designated place and the battery is clamped with the pneumatic cylinder at positive and negative terminals. Then the current, discharge voltage and voltage is measured and the measured parameters are stored in the control unit. The present invention tests the variable load upto N times. The tested data is then calibrated with specific range. Battery is declamped from the system. If the tested parameters are in the predefined range, the battery moves on to the next stage otherwise it moves out from the conveyor by pneumatic cylinder.
The inventive system also measures the internal resistance of the battery. All the details are sent through the communication channel and reports are generated. This system provides the complete details of the batteries for example, type including test-results and generates the number of batteries accepted and/or rejected.
Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

WE CLAIM:
1. A system for performing high rate discharge capacity test of batteries, comprising:
a load assembly, a control unit, a mechanical assembly and a communication means, wherein the load assembly constitutes a transistor assembly and provides discharge path to the system and consists of N transistors, and X-power transistors, the N-transistors connected in parallel configuration to carry (NxY) Amp current, wherein said each of said N-transistors carries current of Y Amp, wherein said X power transistors connected in parallel and including at least one driver transistor; and wherein said control unit controls the discharge current through the transistor assembly.
2. A system for performing high rate discharge capacity test of batteries as claimed in claim 1, wherein the mechanical assembly comprises a plurality of cylinders, a multiplicity of switches, a conveyor to transport the batteries which are under test to a test clamp and then transferred to an adjacent production conveyor or to a reject conveyor corresponding to test the result, clamping assembly having two leads connected to the output of the electronic discharger unit and wherein position of the leads
is adjusted according to the battery size, said test clamp moves downward direction when the battery under test is sensed and then touches the battery lead to make a rigid contact to carry the required discharge current.
3. A system for performing high rate discharge capacity test of batteries as claimed in claim 2 , wherein the plurality of cylinders comprises one each top clamping cylinder, stopper cylinder, battery clamping cylinder, battery clamping cylinder, rejection cylinder, and stopper cylinder.
4. A system for performing high rate discharge capacity test of batteries as claimed in any of the preceding claims, wherein the multiplicity of switches comprises proximity switches and reed switches, wherein the proximity switches are enabled to activate the sensors to sense the input battery wherein entering for testing, positioning of the battery under the top clamping cylinder, positioning of the battery on the main conveyor, position of the battery to allow the rejection cylinder to push it to the rejection conveyor, and wherein the reed switches are enabled to test the position of the cylinders.
5. A system for performing high rate discharge capacity test of batteries as claimed in any of the preceding claims, wherein the said transistor assembly is operable with digital and analogue inputs/outputs including a
diode (D1), or a MOSFET with internal diode to protect the transistor assembly in case of reverse connection of battery.
6. A system for performing high rate discharge capacity test of batteries as claimed in any of the preceding claims, wherein the discharge operation being implemented with constant current including forced air-cooled power transistors, any battery typed can be tested.
7. A system for performing high rate discharge capacity test of batteries as claimed in any of the preceding claims, wherein in case of rejection, the rejected batteries are transferred to a separate conveyor.
8. A system for performing high rate discharge capacity test of batteries as claimed in any of the preceding claims, wherein the control unit comprises one of a microcontroller, a PLC, ASIC, FPGA.
9. A system for performing high rate discharge capacity test of batteries as claimed in any of the preceding claims, wherein the inputs and output of the system is digital and analogue, which are variables according to user's requirements
10. A system for performing high rate discharge capacity test of batteries as claimed in any of the preceding claims, wherein said assembly is one of a transistor assembly, an electronic circuit which may be passive or other such kind.
11. A system for performing high rate discharge capacity test of batteries substantially as herein described and illustrated with reference to the accompanying drawings.