Printed circuit board for secondary battery repeated pulse discharger

Abstract

To eliminate the effect of noise derived from a cooling Sirocco fan superimposing on an ADC reference voltage of a microcontroller module when measuring the voltage of the Secondary battery, if the drive power supply for the cooling Sirocco fan and the power supply for the microcontroller module are shared.SOLUTION: A Sirocco fan drive circuit, including GNDPWR, is isolated via a jumper switch and power is supplied from a separate power source.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention applies a repetitive pulse current load to a secondary battery using an analog switch time-controlled by a microcontroller module and an FET current-controlled by an operational amplifier, and measures the resulting voltage drop using an ADC. The main purpose is to conduct accelerated endurance tests under repetitive pulse loads on commercial secondary batteries and research prototype secondary batteries. When used as a continuous load, it can also function as a conventional electronic load device. [Background technology]

[0002] Using a printed circuit board makes it easy to wire multiple test circuits. The initial cost of printed circuit board manufacturing was a bottleneck for small-scale production, but as a result of competition for contracts between Chinese companies, even small Japanese companies can now place orders. It is also possible to design four-layer boards using open-source CAD. The design of this invention was carried out using the same type of software, KiCad (https: / / www.kicad.org / ).

[0003] The Arduino Nano is a microcontroller module used by hobbyists and researchers. Arduino has a wide range of libraries and is widely used. Arduino Nano is a registered trademark of Arduino SRL (Italy).

[0004] Sirocco fans used for cooling purposes in personal computers, etc. are electrically similar to DC fans in terms of rotors, and their drive voltage is typically 12V or 5V.

[0005] The fan's drive circuit is built into the fan itself and turns the excitation current on and off.

[0006] Researchers engaged in the research and development of secondary batteries regularly use lead wires with bagworm clips.

[0007] Commonly used electronic components are available through online shopping sites.

[0008] The Arduino Nano has a built-in regulator, and can output DC5V and DC3.3V when DC12V is input externally.

[0009] Arduino is I 2 There is a library for LCD drive that is compatible with C, and LCD display is possible using a 4P connector for power, GND, SCL, and SDA. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent Publication 2023-166943 Secondary battery repetitive pulse discharger

[0011] [Patent Document 2] Patent application 2023-56595 Secondary battery pulse load endurance tester board Summary of the Invention [Problem to be solved by the invention]

[0012] If the power supply for the sirocco fan is shared with the power supply for the secondary battery voltage measurement circuit, noise voltage induced by the sirocco fan may be superimposed on the reference voltage of the Arduino Nano's built-in ADC, affecting the secondary battery voltage measurement.

[0013] If you buy 10 meters of tinned copper wire online, 99% of it will be wasted. Furthermore, unless researchers themselves go to Akihabara in Tokyo or Nipponbashi in Osaka, it is difficult to obtain small amounts of extra-thick tinned copper wire for use in electronic components.

[0014] If the jumper wire is replaced with a twisted wire, the twisted wire is highly flexible and will deform even with a slight pulling force.

[0015] If the end of the insulated wire is stripped and soldered on the backside through a hole in the printed circuit board, the boundary between the wire insulated part and the bare wire will undergo bending fatigue while the lead wire is being routed, causing part of the stranded wire to break. As a result, the flowing current will become unstable and voltage measurements may be inaccurate.

[0016] In mass-produced PCB assemblies, hot melt adhesive is used to reinforce the openings in the coating to prevent bending of the coated copper wires, but most researchers are unfamiliar with using glue guns that melt and dispense resin.

[0017] As shown in Patent Document 1, if the device incorporates this board, simply pressing the tactile switch with the index finger will cause the device to tip over. Therefore, the device should be grasped along the thickness of the device and pressed with the thumb. However, because the device is vertically long, left-handed users are forced to operate it with their right hand.

[0018] If a dedicated LCD sold by a domestic electronic parts store is used as the standard, it may be difficult for overseas users to obtain the LCD directly because the store does not handle exports.

[0019] DIO input / output signals are required to display the device's operating status to a control device such as a PLC, or to perform durability cycle tests while monitoring the battery temperature. To achieve this, it is necessary to solder lead wires directly to the Arduino Nano terminals. However, when the device is disassembled and stored, storing the board with the lead wires attached is not neat. [Means for solving the problem]

[0020] Even if an inductor and capacitor are added to reduce the induced sirocco fan noise voltage, it is difficult to eliminate it due to the steep spike noise voltage. Therefore, the sirocco fan drive circuit, including GNDPWR, is cut off by a jumper switch and power is supplied from a separate power source.

[0021] Most laboratories have leftover insulated twisted wire. Furthermore, insulated twisted wire of around AWG22 is easily available from online retailers. By stripping the insulated wire, passing it through a hole in a printed circuit board, and soldering it, it can be used as a jumper wire. [Effects of the Invention]

[0022] The flexibility of the jumper wire made of twisted wire can be increased by heating it with a soldering iron and letting the solder flow through it, making it harder and more durable.

[0023] If the power supply for the Sirocco fan is a separate power supply, it can be completely separated from the analog / digital circuit power supply, including GNDPWR. If the noise is within the allowable range, turning on the jumper SW and sharing the power supply will eliminate the need for a separate power supply for the Sirocco fan.

[0024] When the thickness of the printed circuit board copper foil is 35 μm, a tin-plated copper wire with a diameter of 0.9 mm corresponds to a pattern width of 18 mm. Therefore, connecting a tin-plated copper wire as a chamfered wire next to GNDPWR contributes to reducing impedance.

[0025] In the case of power sharing, the jumper in the ON state also functions as a supply voltage check pin.

[0026] When a tinned copper wire with bending rigidity is used as a jumper wire, there is an advantage in that it can be used as a single jumper wire without going through the jumper wire dividing hole in the middle of the GNDPWR attached jumper wire (13), thereby reducing the number of soldering points and improving the reliability of the circuit.

[0027] When replacing the positive lead wire of a secondary battery, if the connection with the circuit board is reinforced with a resin such as hot melt, it is necessary to locally raise the temperature to soften it. Softened resin tends to be stringy like natto, requiring skill, but U-shaped wiring makes replacement easy.

[0028] If the users of the device incorporating this printed circuit board are mixed left-handed and right-handed, attach the tactile SW to both. If there are no left-handed users, attach the tactile SW to the right. If only left-handed users are used, attach it to the left side to avoid wasting tactile SW. [Brief explanation of the drawings]

[0029] [Figure 1] A diagram of a pattern on the back of a printed circuit board for implementing the present invention. [Example]

[0030] The printed circuit board in question is a double-sided board with wiring laid on both sides of the board. The normal holes are through-holes that are electrically conductive on both sides. The numbers in parentheses are reference numbers in the figure. The top side of Figure 1 is the right side when the printed circuit board is incorporated into the device.

[0031] The stripped end of the positive lead wire is passed through an independent hole in the corner land of the positive lead wire connection part (19) with the coating still attached, turned in a U shape, passed through an adjacent hole, and soldered to the land on the front side of the printed circuit board.

[0032] When using a thin positive lead wire, the thin wire may be passed through a small hole perpendicular to the U-shaped hole to connect and fix the positive lead wire to the printed circuit board.

[0033] When an external LCD is used, the external LCD connector is soldered to the LCD connector mounting portion (17) on the front side of the printed circuit board.

[0034] The Arduino Nano's DIO external connection is achieved by mounting a connector housing in the DIO external connection hole on the back of the board. As shown in Figure 3 of JP 2023-166943, by placing the connector in the space on the back of the board, it does not interfere with the Arduino Nano on the front side, saving space.

[0035] The GNDPWR annex jumper wire attachment part (13) in the figure shows an example in which the wire is divided into two parts. [Explanation of symbols]

[0036] 11 Tactile SW right mounting part 12 GNDPWR 13 GNDPWR adjacent jumper wire mounting point 14 Fan jumper switch [PWRGND] mounting area 15 Fan jumper switch [12V] mounting area 16 DIO connector mounting area 17 LCD connector mounting area 18 Tactile SW left mounting part 19 Positive lead wire attachment part

Claims

1. A printed circuit board for a secondary battery repetitive pulse discharger equipped with a fan jumper SW [GNDPWR] (14) and a fan jumper SW [12V] (15) that allow the sirocco fan drive power supply and the electronic circuit power supply to be shared or separated.

2. A printed circuit board for a secondary battery repetitive pulse discharger having a printed wiring section GNDPWR (12) and a jumper wire with a bagworm clip hook arranged in parallel, and having a jumper wire mounting section (13) with GNDPWR, which also reduces the impedance of the GNDPWR.

3. When the jumper wire in the previous paragraph is a stranded wire, a printed circuit board for a secondary battery repeated pulse discharger in which wire holes are added and the wire length is shortened in multiple divisions

4. A printed circuit board for a secondary battery repeated pulse discharger, in which the positive electrode lead wire attachment portion (19) provides repeated bending fatigue resistance to the lead wire bending portion.

5. When the thickness direction of the device incorporating this board is held by hand and the tactile switch is pressed with the thumb, the mounting hole for the switch (18) is provided separately on the left side in consideration of left-handed people.

6. When using an external LCD with a general-purpose connector as a replacement for a standard LCD, a printed circuit board for a secondary battery repetitive pulse discharger is provided with an installation hole (17) for the external LCD connector in the area occupied by the display unit of the standard LCD.

7. When expanding the control program by utilizing an empty DIO terminal, the connector hole (16) connected to the terminal and pattern wiring is located within the area occupied by the controller module, and the printed circuit board for a secondary battery repeated pulse discharger is designed to save space on the backside for mounting the connector.

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