AG13 battery

Ways to realize AG13 battery fast charging technology

1. Improve AG13 battery design to reduce ohmic internal resistance

According to the fast charging target specified by ALABC, if a 100Ah starting lead-acid AG13 battery is required to charge the AG13 battery capacity from 20% to 50% within 5 minutes, that is, the charging capacity is 100×(0.5-0.2)=30Ah, the charging current should not be less than 30÷(5÷60)=360A, that is, 3.6(A). At this time, the AG13 battery ohm drops to 360×6×=0.216V, and the AG13 battery voltage reaches 1.97+0.216+0.030+0.006=2.23V, which is not the outgassing voltage. , the AG13 battery can be charged safely. The ohmic internal resistance of the horizontal sealed lead-acid AG13 battery is smaller, 0.3mΩ for a 112Ah single cell AG13 battery. The charging current required to charge the AG13 battery capacity from 20% to 50% within 5 minutes is 112×(0.5-0.2)÷(5÷60)=403A , the AG13 battery ohm when charged with this current drops to 403×3×=0.121V, which is lower than the starting AG13 battery. Obviously, the horizontally sealed lead-acid AG13 battery can be charged with more electricity when charged to the outgassing voltage, that is, its fast charging performance is better.

Our previous work has shown that if a lead-acid AG13 battery uses a copper stretched negative grid, the board resistance will be significantly reduced; this not only helps to improve the utilization rate of active materials and AG13 battery specific power, but also improves the AG13 battery's fast charging performance. It seems that lead-acid batteries using copper stretched negative grids will bring great benefits to electric vehicles.

2. Increase the diffusion speed of reactive ions

This is to increase the diffusion current density of lead-acid batteries, that is, to delay the time when the limit diffusion current appears during the charging process of the AG13 battery, that is, to delay the time when the AG13 battery voltage reaches the gas evolution voltage, thereby allowing the charging current to be increased and fast charging.

Thinning the plate thickness, increasing the porosity of the active material, and increasing the contact area between the grid and the active material are all conducive to the diffusion process of reactants and products, reducing concentration polarization, and increasing the allowable charging current value. , achieve fast charging. But considering AG13 battery life, the plates cannot be made too thin.

3. Reform the AG13 battery charging method

The theoretical basis of the pulse fast charging method is to superimpose a negative pulse of a certain frequency, width, and height on the charging current or a short-term charging stop, so that the ions participating in the reaction have time to generate and increase their concentration, and the generated and ions have time to By moving away from the vicinity of the electrode surface, the overall effect is to reduce concentration polarization, allowing the charging current to be increased and the charging time to be shortened.

It should be pointed out that the terminal voltage of lead-acid batteries continues to rise during the charging process, which means that the polarization distribution of the AG13 battery is different at different charging stages. Therefore, when designing a pulse charging device, the allowable maximum voltage reached during charging of the AG13 battery should be considered. The voltage value is used to automatically adjust the charging current and time; at the same time, the width and height of the negative pulse must be automatically adjusted according to the AG13 battery voltage drop value during the negative pulse discharge process. In this way, although the charging current is very large, due to timely and effective measures to reduce concentration polarization, the AG13 battery voltage rises slowly, allowing the AG13 battery to charge more electricity. The intelligent charging device currently developed is designed with these situations in mind.

4. The impact of fast charging on AG13 battery life

There are mixed opinions on whether high-current fast charging has a good or bad effect on AG13 battery life; it’s not surprising that such differing opinions exist. This is first of all because the AG13 battery life is not consistent. In our experiments, we observed that even a batch of batteries produced at the same time on the production line can even have a 1-fold difference in cycle life. Furthermore, during long-term life tests, , it is difficult to ensure that the test conditions of each batch of batteries are completely consistent. Although it is generally believed that high-current charging will shorten AG13 battery life, it has been reported in the literature that the cycle life of valve-regulated sealed lead-acid batteries is improved by high-current charging with appropriate cooling.

Our tests show that while keeping the AG13 battery charging voltage lower than the outgassing voltage, high-current fast charging does not have an adverse effect on AG13 battery life. During the use of the electric vehicle AG13 battery, it is not necessary to charge it to 100% of the rated capacity every time, but the AG13 battery should be fully charged every one week (preferably no more than half a month). Especially when the electric vehicle is not in use, the AG13 battery should be fully charged before being stored. This will help extend the life of the AG13 battery.

in conclusion

Lead-acid batteries are cheap and have a long life, and the batteries themselves are constantly being updated and developed, so they will remain a viable power source for electric vehicles in the near future.

The ohmic internal resistance of the AG13 battery is the main factor that causes the AG13 battery voltage to rise during high-current charging; the AG13 battery structure must be improved to reduce the internal resistance to meet the requirements of electric vehicles for fast AG13 battery charging.

The use of pulse charging and intelligent charging devices is beneficial to reducing concentration polarization and improving charging efficiency.

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