Following on from the article on ‘Batteryfication’ a previous edition, Peter Vandenheuvel believes now is the time for a broad-brush overview of some of the hazards that could befall the under-prepared battery Installers.

Would you like to be held accountable for a serious injury to you or another installer working for you? Or for injury to the installation owner and their family? Or for the total destruction of a home, other premises or even a multi-storey, from a battery-initiated fire?

No? Then please read on:

DC vs AC hazards

The previous ‘Batteryfication’ article noted – if managed correctly – the overall risk from lithium-ion batteries (LIBs) is low.

But with so many different lithium-ion hazards coming from different directions, it can be very difficult for both installer companies and individuals ‘at the coal face’ to be across them all.

Why? Because, to the uninitiated, the hazards may look the same as those for your usual AC installation.

However, dealing with DC can be an entirely new world for those not trained in working with it, on at least four fronts;

• The potential for an unexpected and possibly catastrophic energy release in milliseconds if a battery fails for any reason.
• Having to work with DC voltages higher and more lethal than on typical 240/400V AC systems.
• The risk of working live on parts of the installation where the battery can’t readily be isolated.
• The behaviour of DC vs AC because DC faults can be sustained for much extended periods compared to AC.

After all, any mishap arising from your lack of training, unsafe or inadequate work practices, inappropriate design, poor equipment selection, unsuitable location and the like, could result in a catastrophic outcome from which any or all involved may never fully recover.

And with the trend to install more and more – and larger capacity – batteries, the problems won’t be going away any time soon.

So who’s responsible?

You guess! The first thing whoever is injured or has suffered a fire (or any other loss) will be looking for is someone, like you the installer, to blame. And it only becomes worse if their insurance or lawyers get involved.

So, all of a sudden, the claim of negligence – your negligence – will be featured very prominently in any discussions.

And, as a catastrophic outcome is usually the irrefutable proof of someone having done something wrong, that negligence will be very difficult to disprove.

It would be very wise for you to have indisputable proof you have done all the due diligence and taken all steps to deal with all the hazards and ensured yours was a ‘safe place of work’ with ‘safe working methods’ with all potential risk areas identified and under control.

And although your arc flash suit may not be needed just yet, your undivided attention here may well be worthwhile, as being forewarned is being forearmed and, where needed, the suit or other PPE will – in that case – be at hand to avoid the disaster.

Some background

Batteries have come a long way since being first invented by Alessandro Volta in 1799; almost 225 years ago. And since that time, they have undergone many revolutionary and innovative changes, in both design and cell-voltage outputs.

They have become indispensable for every bit of technological kit needing off-line electrical support. And are now also seen as the quick fix to reduce the ever-upward spiralling electricity costs the politicians have sprung on us. So much for the costs going down by us getting on the ‘renewables’ wagon.

But which batteries?

Technically, with the right controls almost any rechargeable battery type could be used.

But the currently best-performing and technically advanced batteries are the LIBs. This is because their kilowatt-hour (kWh) per kilogram energy density is much greater than its nearest rival.

And they are fast becoming the battery of choice for static-battery applications.

So, this article is mainly focused on the LIBs, as most of us are already familiar with the other types that have been around a long time and are much better understood.

Because the increased use of these lithium-ion types as stationary batteries has generally only been taken up in more recent times, their performance as they are installed, operated and at the end of their lifecycle, in terms of safety and the hazards encountered, is still being evaluated.

Therefore, all the more reason to take extra care doing so.

There are current warnings

It should be noted warnings on their hazards both in Australian and overseas jurisdictions are in place. Attention is also drawn to an ERAC document (see later under Standards to reference) that will be of interest to current and would-be installers.

Also, this article is not intended to be an ‘all you ever wanted to know’ one, but more focused on making installers aware of some of the more important safety and hazard issues and how to mitigate them.

This recognises also that each installation is different or will have different issues arise, so is intended as a guide on what you need to consider and then adapt and ‘fill in the details on’ as they apply to your business.

Some ‘batteries 101’

Why are LIBs now gaining popularity? It’s all to do with chemistry.

Ni-Cd and Ni-MH cells only manage around 1.2V per cell. Carbon-Zinc and Alkaline do a little better at about 1.5V, with lead–acid batteries previously topping the list at a nominal 2.2 V for each cell.

Then along came lithium-ion-based cells with a chemistry that produces 3.7V; almost double that of the lead-acid type.

However, although first invented in the early 1970s they have only been commercialised in the early 1990s.

Why so popular now? Well, a typical 1kg L-I battery can store 150 Watt-hours (WH) of electricity compared with a NiMH unit (100WH – 1.5kg for 150WH) or a lead-acid unit (25WH or 6kg for 150WH).

So, lead-acid types are six times the weight for the same output.

Introducing the BESS

Typically, storage battery installations are known as Battery Energy Storage Systems (BESS) and are usually separated into three groups;

• Pre-packaged BESS battery ‘modules’ (enclosed factory interconnected battery cell arrangements – with little or no smarts).
• Pre-packaged BESS battery ‘systems’ (enclosed factory interconnected batteries with other components such as a charger control or inverter).
• Custom-made BESS battery ‘banks’ (individual batteries installed with other peripheral components and interconnected as ‘bespoke’ arrangements).

The decision to use a specific BESS type will be influenced by factors such as price, available space, ease of installation, operation and maintenance etc.

A word of caution however, for all that don’t want to be ‘bespoke battery gurus’; it would be very wise to stick to the more packaged ‘BESS battery systems’ to limit your overall risk to the installation only and so not responsible for the battery and the smarts.

They might be stationary but…

The new generation LIBs are much more complex than some installers and certainly, many end users think.

We may still liken them to lead-acid car batteries. But these only generate about 2V per cell, so if the battery is 12V then it has six cells connected in series. Also, there is just the occasional distilled water top-up and getting a new one when they go flat too often.

There is much more to LIBs.

To get to the higher energy capacity needed in a stationary battery, the energy it has to deal with in and out – the amps and volts – is much higher.

So most have both the cells in series to get the volts, as well as having the series of ‘cell strings’ in parallel to get the amps. Like in a matrix.

Basic Lithium Ion battery operation principles

As mentioned earlier, the LIBs as ‘BESS systems’ generally comprise cells stacked in modules or a matrix and also with temperature sensors and onboard smarts to manage the individual cells.

On charging, energy flows into the cell and lithium ions go from cathode to anode through the electrolyte and on discharging, the energy moves through the load and the lithium ions move in the opposite direction. The battery then has to be recharged.

But there is a lot more that goes on in the battery.

Many cells and battery types are constructed so, on excessive core heat (generally 54-55^oC), the material separating the cells responds, stopping the transfer of ions to prevent it reaching the ‘thermal runaway’ threshold and preventing the cell from ‘venting with a flame’.

There is normally also a switching device to prevent overheating from current surges to protect the battery.

Do they last forever?

No. Ultimately, due to continual charging and discharging cycles (especially deep charging or discharging cycles), there is a small ongoing loss of ions that ‘don’t make it back’ which eventually reduces the battery performance to a point where it must be replaced.

Because of the loss of ions, the voltage is reduced so the cell makes up for this by increasing the current flow.  This, due to the I²T phenomenon, considerably increases the heating and adds to the risk of a ‘thermal runaway’, especially in situations where the battery is delivering a constant load.

So regular monitoring of battery temperature would become part of any servicing protocol, especially near the battery’s ‘end of life’.

Any disadvantages?

Like with most things in this world, there are always some ‘cons’ to counter the ‘pros’ but apart from those covered here associated with installing the batteries, these will be of little consequence and omitted as irrelevant.

Battery hazards and consequences

As noted by Worksafe Queensland and other authorities in other jurisdictions, “Energy Storage Systems, for homes or small commercial buildings”, observes “batteries are a serious safety risk and any undertaking of such installation must ensure the workers and the general public at large are safe”.

Also for the readers, to optimise your new opportunity you may like that list to include in that; “small and larger industrial as well as larger commercial, mining and the like installations”, and “the protection of the installations and the premises the batteries may be installed in”.

Causes

The main causes of hazards include, but are certainly not limited, to;

• Poorly designed systems or main circuit arrangements
• Incorrect equipment and material selection
• AC-only rated or uncertified DC equipment on DC circuits
• Incorrectly rated main circuit protection devices
• Insufficient isolation points or lockout facilities
• Under-rated interconnection cables or busbars
• Excessive ambients, poor location, poor ventilation,
• Mutual heating from adjacent batteries or devices
• Live part access or exposure, or covers not fitted,
• Poor or no isolation procedures
• Poor workmanship and or work practices,
• Lack of training and or lack or non-use of PPE
• Water, moisture or foreign object ingress
• Puncture or vehicle collision impact damage
• Incompatible or poorly selected peripheral controls
• Multiple incompatible batteries or mismatched devices
• Overheating and or thermal runaway
• Internal battery ignition due to overheating
• Over or under charging
• High rate of charging & discharging
• Unsafe or no work procedures for battery connection

It must be remembered both the input from the charger (and or other DC input) as well as from the battery to the load are DC and will always be energised downstream and upstream to their point of first isolation.

In addition, any arcing that may occur may be moderated in a typical AC circuit – because the AC voltage passes through the ‘voltage zero’ twice every cycle and there is a destabilising oscillating magnetic field around it – but this doesn’t occur in a DC circuit.

So in those situations, any arc strike will continue arcing until the materials feeding into the arc are exhausted, the energy source is finally depleted or when the arc plasma of itself becomes so unstable that it just ‘gives up’.

The consequences 

In reading the above causes, it must be noted that some or many of the consequences can be combined. This is because even if the causes may be different, most consequences will ultimately escalate in stages from; overheating, internal short-circuiting, arcing, fire, electrical explosion, damage to the battery, damage to immediate surroundings, destruction of premises, exposure to toxic substances, exposure to smoke, respiratory failure, carbon monoxide poisoning, electric shock, electrocution, shock blast injuries, hospitalisation, rehabilitation, with many of these resulting in catastrophic outcomes including in one or more deaths.

Also, if a battery of sufficient capacity is damaged this may result in the release of all the energy contained in it in milliseconds, so the access and egress space around batteries must always be kept unobstructed.

In addition, according to the I²T rule, the energy release for a battery – even just double the size of another – can well be four times more destructive, so four times the blast or flame.

With such potentially catastrophic consequences, even if a risk analysis determines a low probability of it happening, the outcome could be extremely severe.

This, coupled with the fact the consequence can be foreseen, should warrant sufficient beforehand effort to prevent it from happening as any defence seriously will be undermined and the lack of action considered grossly negligent.

A good thing to keep in mind.

The hazard to people

Although that is briefly mentioned above, it’s always going to be the first and foremost issue because nothing will get people’s attention more than a serious injury or death.

It’s therefore well worth repeating the consequences that can directly affect the well-being of you, your staff, your customers and the community at large. So think about those you ultimately have a legal as well as moral duty to protect.

This list includes;

Injuries to persons you know; those working on, switching, testing, adjusting or being near the batteries. Injuries such as flash burns, fires, explosions, exposure to hazardous chemicals, smoke inhalation, electric shock, electrocution and possible death.

Injuries to person you may not know; those who you may or may not know but may be directly affected by your work. People such as the occupants of the premises or their visitors. This could include injuries (or worse) from fires, smoke inhalation, exposure to hazardous chemicals and electric shock and electrocution, to persons living (including sleeping) in premises or nearby.

And there could no doubt be other consequences including losses incurred in any form from; income, lost rental, alternative accommodation as well as direct costs for any hospitalisation and other health-related issues.

Now, this is not to unduly frighten anyone, but it does highlight the possible seriousness of the potential outcome and for those involved to realise the importance of taking sufficient care to ensure the potentially negative consequences in these ‘less chartered waters’ are eliminated.

Standards to reference

There are a number of standards directly associated with the installation of batteries as well as an ERAC publication “Battery Energy Storage System Installation requirements” that are noted earlier. These include;

• AS/NZS 3000 – The Wiring Rules
• AS/NZS 3011 – Secondary batteries in buildings (parts 1 & 2)
• AS/NZS 4777 – Grid connection of energy systems
• AS/NZS 4509.1 – Stand-alone power systems – installation
• AS/NZS 5033 – Installation of PV arrays
• AS/NZS 5139 – Electrical installations – safety of battery systems
• AS/NZS 60898.2 – Circuit breakers for household installations AC & DC
• AS/NZS 60497.3 – LV switchgear & control gear, switches & disconnectors
• AS/NZS 61439 – Low voltage switchgear and controlgear
• AS/NZS 61851 – Electric vehicle charging systems
• AS/NZS 62040 – Uninterruptable power systems (parts 1 & 2)
• The Australian National Construction Code (NCC)

As noted, the ERAC publication “Battery Energy Storage System Installation requirements” places restrictions on where a battery energy storage system (BESS) can be located as it is considered a source of ignition, and the ERAC publication as well as the Standard AS/NZS 5139 should be referenced by any person installing or relocating a LIB.

So where to from here?

Well, as noted earlier, LIBs are generally considered safe to install and use providing this is done correctly. And to do that you need to make sure the work you and your people do is compliant and safe to the best of your ability.

Therefore, as you can’t control those things outside of your direct control you have to protect your interests as best as you can with the issues you do have control over.

And also to make sure you have indisputable proof of your efforts in that regard; to keep a detailed record of how you have gone about it.

So here is a (hopefully) helpful starting list of those extra issues to consider in addition to any controls you already have in place. Please note however it is not all-inclusive and is only a guide;

Training; ensure all are trained in all aspects of the work, including;

• How DC hazards are different to AC hazards
• How batteries present their own risks
• Reinforcing your ‘no working live’ policy
• Reinforcing your work practices & procedures
• Recognition batteries remain live at all times
• Strict isolation and de-isolation procedures
• Safe battery handling
• Following manufacturer instructions and Standards
• Having toolbox meetings prior to starting
• Regular refresher training
• Retain records of all training

Systems; have tried and tested systems in place to;

• Confirm persons are adequately trained
• Undertake safe working on live batteries
• Carry out DC Isolation and de-isolation
• Work on energised systems
• Inspect, test and set to work
• Decommissioning and dispose

Design; to confirm;

• Use of only compatible peripheral controls and devices
• Voltage, amperage and fault level meet specification
• It is a safe installation
• The safest number of isolation points & lockout facilities
• Equipment selection for DC-certified equipment
• Only BESS battery ‘systems’ are installed
• Risk of temperature rise is minimised
• Correct overload & short-circuit protection settings
• Protection from ‘thermal runaway’
• Documented design review done
• Documentation is retained

Installation; ensuring the installation;

• Confirms persons are adequately trained
• Complies with ERAC publication see ‘Standards to reference’
• Has adequate space, access and egress
• Has adequate access to operation and maintenance
• Is in a suitably protected non-corrosive area
• Presents no risk of puncture or collision damage
• Is in a suitable well ventilated location
• Has no excessive-ambient environment
• Presents no risks for water ingress
• Has no mutual heating from adjacent equipment
• Has totally non-accessible live parts
• Has all required isolation points & lockout facilities
• Follows pre-prepared SWMs and WMSs
• Ensures PPE use, especially in higher risk situations
• Includes installing appropriate fire extinguisher(s)
• Retains all commissioning records

A new service opportunity?

Yes, as it can add impressively to your services, set you apart and help you build your customer list.

This is because LIBs are more complex and they could do with an annual health check, especially as they start to age. They may be included as part of an overall battery, PV panel and solar system’s ‘periodic inspection and servicing plan’ to offer you an added business opportunity.

And once you have a regular contact with the user over the years – no matter how little contact but as long as it is regular – you are almost certainly guaranteed the order when its ‘replacement time’ for the battery, PV panels, etc, as well as any other little or large electrical and allied jobs ‘along the way’.

Do it right and this is an opportunity to build on your regular customer base of ‘loyal life-time customers’ with peace of mind knowing you have done your best to protect all involved.