There have been a lot of attempts before, and many companies in the back have basically not adjusted their strategies according to their usual strategies.
1. Battery balance is limited, and the effect needs to be evaluated with certain parameters.
2. The battery is balanced in the HEV and EV, and there is a big difference.
3. The effect of battery balancing must be gamed and compromised with cost and additional energy consumption.
Reasons for balance:
Both EV and HEV require a large amount of transient current during the charging and discharging phases, and are represented by braking energy recovery during charging. For a lithium battery, such a large charging current may be that a partially full battery directly exceeds the damaged voltage range.
The discharge phase requires high instantaneous energy when the motor is started and the car is accelerating. A large discharge current may cause some batteries to be in a state of deep discharge, one affecting the output current and the other being the battery itself.
For the above-mentioned current calculation, it has a great relationship with the whole vehicle. I believe that after finding sufficient data and calculation formulas later, some calculation and evaluation formulas can be established for the parameters of the energy management unit power unit and the final vehicle body environment. In the comparison, when I sell some "electric vehicles", I can make some preliminary assessments.
This mechanism is still very useful on the HEV small battery, even to PHEV10Kwh is quite useful, to the large-capacity EV battery, the 150Ah and 200Ah really need other ideas.
Equilibrium strategy for 100mA and 30mA equalization current effects
The magnitude of the equalization current mainly affects the equalization time:
The equalization time is calculated as follows:
Equilibrium time T = equalization capacity / equalization current
For B01_Phase2, take the 5% SOC difference as an example:
Equilibrium capacity = ΔSOC* nominal capacity = 5%*5.2Ah = 260mAh
100mA equalization current equalization time = 260mAh/100mA = 2.6h;
30mA equalization current equalization time = 260mAh / 30mA = 8.7h;
Thermal design
Dissipative equalization circuit mainly studies the thermal design capability of equalization resistor
Component level: thermal resistance and junction temperature
System level: ambient temperature, cooling method, thermal performance of PCB
Resistance heat dissipation model:
To make the actual temperature Tj within a reasonable range, design:
a) reduce the ambient temperature;
b) reduce the thermal resistance of the components, such as selecting a large SMD package;
c) optimize the pads of the PCB, such as increasing the area and thickness of the copper foil;
d) reduce the power consumption of individual components, such as using multiple resistors in parallel;
Example:
a) Select vishay's chip resistor specification analysis, such as taking 2512 package / 1W specification:
Ta takes the battery with the highest temperature resistance of 65 ° C;
The junction temperature of the resistor is 155 ° C;
The resistance is 33.2 ohms, the operating current is 0.1 A, and the actual power consumption is 0.332 W.
Use mCu design (worst PCB design: 35um copper foil layer, 1.6mm PCB thickness, copper coverage ≤ 20%)
Actual temperature Tj=65 + 110*0.332= 101.52 °C
Meet below the junction temperature requirements;
If the PCB design is strengthened, such as using the sCu design, the actual temperature will be lower;
2. Cost and cycle
The application of resistor components is common, the cost difference is not significant, such as vishay's 1210 package size patch, the price is around 0.16 ¥, even if the selection package is larger 2512, the valuation will be within 0.3¥;
The design uses 矽 film heat conduction, with a size of 70mm*20mm*2mm, about 1.5¥. If the board is used, the piece will be OK, which will increase the cost by 1.5¥;
PCB optimization design, such as increasing the thickness of copper foil, 2OZ/4OZ, the PCB area cost is increased by about 30%; it is also possible to increase the thickness of the copper foil design, increase the exposed copper surface in the production process, and make the appropriate thickness of tin or steel mesh. The use of wave soldering and reflow soldering can be operated, and the production cost is not significantly increased, but the thermal conductivity of tin is lower than that of copper, but the cost can be well controlled;
The design development cycle is related to the design team's experience and capabilities. If the design parameters are uncertain, it is necessary to evaluate the feasibility of each program and extend the development cycle.
Consumer Electronic Cable Assembly
Consumer electronic Cable Assembly: The product is mainly used in the signal, power, power transmission machine control inside the home appliance.
Common consumer electronic cable assemblies include air conditioner power wiring harnesses, water dispenser wiring harnesses, computer internal power cords, coffee machines, egg beaters and other signal lines, TV wiring harnesses and other product wiring harnesses that we can call white goods. The wiring harness is the main body of the circuit network. There is no home appliance circuit without a home Wire Harness . At present, whether it is a high-end luxury home appliance or an economical ordinary home wire harness, the braided form is basically the same, which is composed of wires, connectors and wrapping tapes. Home appliance wires, also known as low-voltage wires, are different from ordinary household wires. Ordinary household wires are copper single-core wires with a certain hardness. The consumer electronic wire harnesses are all copper multi-core soft wires, some soft wires are as thin as a few hairs or even dozens of soft copper wires are wrapped in a plastic insulating tube (polyvinyl chloride), which is soft and not easy to break. Common specifications of wires in consumer electronics harnesses include wires with a nominal cross-sectional area of 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 4.0, 6.0, etc. square millimeters, each of which has an allowable load current value for use in different power electrical equipment. Different gauge wires.
The consumer electronics connection cable harness industry has had a profound impact on people's lives, cutting into all aspects of life from market conditions, industry services, service conditions, and market scale. Therefore, Kable-X has made an in-depth understanding of the consumer electronics industry to provide customers with better wiring harness.
In addition to Instrumentation Cable Assembly, we also have Vehicle cable assembly and Industrial Cable Assembly.
Consumer Electronic Cable Assembly,Power Cord Cable Assembly,Power Cord Cable For Sale,Cable Assembly Prototyping
Kable-X Technology (Suzhou) Co., Ltd , https://www.kable-x-tech.com