Repair of high-voltage batteries of Toyota hybrid cars

Failure of Toyota hybrid batteries is a common problem that our customers come to us with. The battery cells degrade, making it impossible for the car to operate normally. We solve the problem in several ways: by installing a new high-voltage battery assembly or by checking the condition and replacing only the faulty modules.

Although the degradation of the high-voltage battery cells of a hybrid car is a natural and inevitable process, for the car owner, its failure always occurs "unexpectedly". However, this is not a death sentence for the car itself - the main thing is to contact professionals for repair, or rather, us at STS.Electro, because it is here that the best electric vehicle and hybrid specialists in Warsaw work. Let us tell you how we restored the batteries on Toyota Prius and Camry cars.

Replacing the Toyota Prius 30 high-voltage battery

We received a third-generation Toyota Prius (ZVW30). The owner was bringing the car in to have the high-voltage battery replaced, as the one that was on the car was no longer working properly. Before replacing the battery, we connected the car to the diagnostic system. However, we were unable to find any errors - apparently, the owner of the car had removed them using a portable scanner connected to a smartphone. Obviously, this was done in order to get to the service on his own.

Despite the fact that the nature of the work was known, we still decided to find out the state of the battery. To do this, we started the internal combustion engine and put the gearbox in N (neutral). Unlike in P (park), the high-voltage battery is not charged, but rather discharged. To enhance the effect, we switched on the air conditioning - so it will discharge more.

Purpose: we need to cause an error to appear in order to correctly diagnose the fault, to determine which module in the battery is faulty. And they appear only when there is a certain voltage difference between the modules.

It should be noted that in Toyota hybrid cars, a conventional engine starts only when the battery charge level is 30% or higher. Here, it is not a conventional starter that starts it, but the hybrid's electric motor. Therefore, you need to monitor the battery discharge level. It should also be noted that the system is insidious: if the battery is low, or the petrol engine cannot start (for example, due to problems with the fuel pump), the car starts for a short time, 10-15 seconds, runs and stalls. This finally discharges the high-voltage battery.

 

So, we managed to check the battery in the end, and the central modules turned out to be unsuitable for further use. The battery was completely disassembled, and new batteries similar to the factory ones were installed. We reassembled it using the accessories that came with the kit: temperature sensors, balance wires, tyres, and fasteners. In addition, we cleaned the insides of the battery fan while it was removed so that the debris that accumulates there does not interfere with the operation: it does not create imbalances and extraneous sounds.

The battery was assembled and installed on the car. It starts up, everything is fine, there are no errors. We trained the current sensor through the diagnostic system, recharged the battery, and made a test drive. The car can be handed over to the client.

Replacing Toyota Camry Hybrid battery cells

A 2015 car came to us with a similar problem - a complaint about the hybrid system. But here the owner did not offer a solution, we had to find it. However, everything else was the same: the errors were also removed using a portable scanner, which made our work much more difficult.

We removed the battery from the car to diagnose it on a special stand developed by our own brand. It is very convenient and informative, as this equipment allows you to check the capacity and charge each individual cell at the same time, which reduces the operating time and improves the quality of work and reduces the likelihood of errors.

After several charging/discharging cycles, it was found that only 9 out of 34 battery cells were suitable for further use. The rest had to be replaced. For this purpose, we used tested and refurbished batteries from our exchange fund. We assembled the battery and tested it again. The device showed a slight difference between the cells - such a high-voltage battery will work no worse than a new one.

We assembled the battery, installed it on the car, and made a test drive. The car is ready to be handed over to the customer.

In conclusion, here are some tips on how to extend the life of a hybrid car's high-voltage battery.

1. Such cars do not like long downtime, it is advisable to use hybrids constantly, as often as possible.
2. High temperatures are more harmful to batteries than low temperatures. Especially for those models where cooling is air, as in the above cases.
3. High-tech equipment is damaged by unskilled repairs. Even a simple reset error can seriously complicate diagnosis.

That's why don't hesitate to contact us at STS with all the problems related to the hybrid system, as well as other malfunctions. We will return your car to its factory condition.