Rebuilding one cell at a time

There’s plenty of life left in those dying EV and hybrid batteries, even after the warning lights have begun to flash on the dash - they just need a bit of rejuvenation.

So says MTA member Nalin Senanayake, who has the technology to rebuild them, just like they did with Steve Austin in the 1970s TV show, Six Million Dollar Man. Luckily, it’s not as expensive and has the bonus of saving them from the scrap heap.

Nalin sees it as doing his bit for the environment while providing a sought-after service.

“It really reduces the carbon footprint because rather than throwing it out or sending it to the recyclers, we put life back in, and there is still plenty of life in it.

“Costs have come down, the early EV Toyota batteries were $10,000 and they have come down a lot over the years,” he says.

Nalin was an early adopter of hybrid technology. He started working on Toyota’s first-generation Prius in 2002, qualifying with Toyota New Zealand and then going out on a limb building his own business, Ultimate EV, specialising in EV and hybrid battery reconditioning.

His business has grown with servicing, a car yard, and aftermarket new battery imports, along with specialty technicians rejuvenating used batteries.

“I would say the number of EVs coming in the door are doubling each year and to my knowledge we are the first business of its kind to be dedicated to EVs and hybrids,” Nalin says.

The process

Once the battery is out of the car and up on the test bench, technicians get to work and analyse it.

The faulty modules are identified and replaced, and the battery is balanced so the output from all the cells is equal.

“Some batteries have 96 modules and only six might be causing a problem and all that needs to be done is replace the six modules and balance them, so they are working at the same level,” he says.

There are several technical steps that need to be taken with the nickel-metal hydride batteries to get them back to good health, he says, and with lithium batteries a computer is used to rebalance them and analyse the cells or modules so any that are not performing well can be replaced.

“The state of health in the EV lithium batteries is important and we match each module in the battery, so it is even and then it is ready to go.”

Because of the number of Toyota hybrids in the country’s fleet, Nalin says it isn’t time-effective to recycle the original battery pack and put it back in the same vehicle, so it is exchanged with one that has already been reconditioned. The original battery is then tested and refurbished, ready to be exchanged.

Nalin also imports aftermarket batteries from China and says they are as good as, if not better than the original.

“When we get them, they only have storage capacity in them; we charge them and balance them before they are sold.”

If a battery is too far gone and it isn’t viable for rejuvenation, Nalin sends it off to a nominated recycler who extracts all the recoverable components, and what can’t be recycled is shipped overseas, he says.

NiMH versus Li-ion

Nickel-metal hydride (NiMH) batteries have long been a popular choice for hybrid cars and have also been utilised in some EVs. One of the primary advantages of NiMH batteries is their robustness and durability. These batteries have a long cycle life, which means they can endure many charge and discharge cycles before their performance begins to decline. Not only that, but NiMH batteries can deliver high levels of power output, enabling quick acceleration and overall strong performance in hybrid cars and EVs.

Some disadvantages associated with NiMH batteries when compared with other battery technologies are they have a lower energy density, meaning they store less energy per unit of weight or volume. This translates to reduced driving ranges, which can be a significant drawback for consumers concerned about range anxiety. And, NiMH batteries have a higher self-discharge rate than lithiumion batteries, which means they can lose a more significant portion of their stored energy when not in use. This characteristic can be particularly problematic for EVs that are parked for extended periods.

Lithium-ion (Li-ion) batteries have a higher energy density than typical lead-acid or nickel-cadmium rechargeable batteries. This means that battery manufacturers can save space, reducing the overall size of the battery pack.

Lithium is also the lightest of all metals. However, Li-ion batteries contain no lithium metal, they contain ions. For those wondering what an ion is, an ion is an atom or molecule with an electric charge caused by the loss or gain of one or more electrons.

Both NiMH and Li-ion batteries have their advantages and disadvantages in automotive applications. The choice between the two depends on factors such as cost, performance requirements, and the environmental considerations of the vehicle manufacturer. In recent years, the automotive industry has been leaning more towards using Li-ion batteries due to their higher energy density and improved performance for electric vehicles.

*Source. science direct.com