Replaceable batteries (again): battery disaster illustrated

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Long time readers will remember my empassioned editorial on the subject of replaceable versus sealed batteries a year or so ago. Although putting forward the various arguments for and against the concept (and quoted below), it's clear that I come down clearly on the 'replaceable' side of the fence. Not that the industry listened to me, with almost most designs in recent times coming with sealed batteries. But do see below for an illustrated example of one of the things which can go wrong with a Li-Ion battery. 

From my earlier editorial:

  Sealed batteries  (Traditional) Replaceable batteries
  • Batteries can be custom designed/shaped to fit around other internal components, leading to greater volume and greater charge capacity.
  • With no battery door, latch or sprung battery contacts, the phone can be simpler in construction and stronger.
  • There's no possibility of the user putting in third party 'dodgy' batteries and thus compromising the rest of the phone's performance or risking fire etc.
  • Batteries can be sourced relatively inexpensively, kept as spares in a pocket and swapped in and out as needed.
  • When a battery's capacity has degraded significantly, you can just throw it away (safely) and buy/insert a new one. 
  • In the event of a serious battery malfunction, you can spot the issue (probably early on) and prevent damage to your phone.
  • In the event of serious software or hardware malfunction, you can 'pull' the battery to drain charge from the device and then restart it from scratch.
  • Where safe to do so, third party batteries can be used to provide higher capacity within the same form factor.
  • When the battery's flat, there's no alternative but to charge the phone directly, via mains, USB or a portable charger.
  • When the battery's capacity has significantly decreased/degraded, you have to take the phone to an approved service centre and pay whatever the manufacturer demands to get the battery replaced.
  • If the battery goes 'bad' and swells up or leaks, your device can be permanently damaged.
  • On a long, demanding day out, you can't take a 'spare' battery (just in case).
  • Battery tends to be smaller and capacity tends to be lower, due to the volume needed for the sprung contacts, support struts, battery door, latch, etc. 
  • Batteries have to be (roughly) of standard shape, for ease of insertion and storage.
  • You have to watch out for third party 'counterfeit' batteries, which may not provide what they say and may even be dangerous.

To me, the 'disadvantages' of sealed batteries are almost showstoppers, yet still the industry (Samsung aside) persists in this integration. Perhaps coincidentally, perhaps not, Samsung, the biggest manufacturer in the industry by a country mile, is fully committed to replaceable batteries? Could it be that people (like me) really do want this feature in our phones?

Here though, I'd like to highlight the phrases in italics above. We don't hear of batteries going 'bad' very often and I for one am careful to always store phones with a decent amount of charge in their cells, just in case. However, just occasionally the chemistry inside a Li-Ion battery does go rogue, either triggered by mis-use or just bad luck. In this case, I noticed my 2010 Nokia C7 (last used about 6 months ago and stored with what I thought was a decent amount of charge) battery cover looking a little more 'convex' than usual. Popping it off, I immediately spotted the problem. Here's the Nokia original BL-5K battery:

Bulging Li-Ion battery

Bulging Li-Ion battery

Quite a bulge! What's happening is that part of the internal chemistry inside the Li-Ion cell has broken down, physically changing the structure of the electrolyte and causing the production of (potentially dangerous?) gas. 

The solution for my (now quite old) Nokia C7 was simply to throw this misbehaving cell away (responsibly) and to slot in a spare BL-5K that I happened to have lying around - and all was well. But the exact same thing could happen to an internal (sealed) battery in one of the modern flagship Nokia Lumia devices, or to that in an iPhone or Xperia Z or whatever. 

What would happen in practice if such a battery fault developed in a sealed design? The charging/performance would get markedly worse and the battery swelling would put strain on the other internal components. If in warranty, the phone could be taken to an authorised service centre, of course, for the battery to be swapped and (if necessary) the device replaced. Out of warranty, you'd be looking at a sizeable repair bill, from the battery cost and labour to dismantle and rebuild the phone, to paying for a complete replacement.

So yes, a cautionary tale and hopefully a situation that most people will never face. But surely this is yet one more reason for manufacturers to stick to designs in which the user can check on - and replace - the battery if needed? 

I've a feeling I'm going to be ranting about this for several years to come. Thankfully, my Symbian devices (with one exception) all have replaceable batteries. In the Windows Phone world (this being AAWP too), maybe I should go buy a Samsung Ativ S after all? Comments welcome - I suspect others will also have string feelings here!