Why Do PSP Batteries Swell? Causes And Solutions

Before the Sony PSP, handheld consoles just used regular AA batteries- Nickel Metal Hydride and Nickel Cadmium. Sony and Nintendo made more powerful handhelds without compromising on size and weight, using battery technology that mobile phone manufacturers had adopted since the 1990s. One downside of lithium-ion batteries is swelling, and the PSP suffers from this phenomenon.

Why do PSP batteries swell? Causes and solutions shall be discussed in this article, but the primary reason behind swelling is a process called outgassing. This usually happens to old PSP batteries that are left inside the console after being completely discharged, and the issue is often exacerbated in hot climates.

Swollen batteries aren’t unique to PSP, as a quick Youtube search will bring up hundreds of videos demonstrating this phenomenon across a wide range of portable devices. It usually happens to old batteries that have been left for several months inside the device, but even new batteries can face this problem due to manufacturing defects. Hence, you should never cheap out on a replacement battery and always purchase one that is well-reviewed (finding OEM batteries for PSP is very hard nowadays).

Why Do PSP Batteries Swell? Causes And Solutions

You see, each battery is a chemical reaction in progress with two sides- an anode, and a cathode. The anode is the negative terminal, and it provides electrons to the cathode which is the positive terminal.

While discharging, lithium ions stored in the anode flow into the cathode. Recharging reverses the flow, and lithium ions flow from the cathode to the anode.

To facilitate this electron flow, there is a substance called the electrolyte between the anode and cathode layers. Depending on the battery chemistry and manufacturing process, this can be a liquid, gel, or solid. Since everything is wrapped so tightly in a lithium-ion battery pack, there is a separator layer to prevent contact between the anode and cathode.

This separator is non-conductive and has microscopic pores to soak up the electrolyte, allowing for the free passage of lithium ions. Over time, a small amount of current passes through this separator layer even when the battery isn’t connected to any load. This is called self-discharge.

Batteries like the one in PSP have a protection circuit to prevent overcurrent and overvoltage. However, self-discharge is inherent to battery chemistry and can’t be stopped. A fully charged battery will self-discharge, as will a depleted one.

However, depleting your PSP battery and leaving it in the console will cause a chemical reaction that releases gases. Since the battery is sealed with an outer plastic shell, these gases have nowhere to go. And your battery gets bloated over time.

If the issue persists for a long enough time, this bloating might break the separator layer and cause a short circuit. Many lithium-ion batteries have caught fire because of this. To prevent this issue, you should periodically charge your PSP battery- even if you don’t use the console much.

Overcharging your battery will also increase self-discharge rates. Ideally, you don’t want to charge beyond 80%. Storing your PSP in a hot and moist environment also accelerates the outgassing process that bloats the battery, so keep it somewhere cool and dry (25°C is perfect).

How Do I Know If My PSP Battery Is Bad?

The most obvious sign is a rear cover that won’t fit properly. Bloated batteries push this cover outward, and you can’t hinge it properly anymore. Another sign of a bad battery is the smell.

Don’t sniff it up close because these are poisonous gases. Instead, put the battery at arm’s length and use your hand to waft the gases in your general direction. You should get a metallic or acetone smell.

Once you’ve confirmed that your battery is bloated, remove it carefully. Use gloves or tongs, instead of directly touching the battery. Replace it with a new battery, and take the old one to a battery disposal center.

How Do I Stop My Battery From Swelling?

Over time, a lithium-ion battery gets old and loses its cell chemistry. This can cause high rates of discharge and reactions that release gases. You can’t stop the process entirely, but there are steps to mitigate and delay it.

First, you should keep your PSP battery (or any lithium-ion battery for that matter) between the 20% to 80% sweet spot. Meaning, you never let it discharge below 20% or charge above 80%. I know this isn’t always possible in the real world, but try to stick to this general rule when you can.

Next, you should never leave a discharged battery inside your device for several months at a time. Voltage levels drop dangerously low, and the cell chemistry changes to the point where gases are emitted. Take out the battery every few weeks or so, and charge it partially.

Finally, store the battery in a cool and dry place. Heat and humidity accelerate the self-discharge rate. Excess heat can cause thermal runaway, and a potential fire (so don’t leave your PSP on the car dash during a sunny day).

Should I Be Worried About A Swollen Battery?

For most folks, a swollen PSP battery is no big deal if you manage to find and correct the issue on time. No, don’t poke a hole in your battery to drain the gases. There’s a chance the anode and cathode will touch each other when you do that, shorting the circuit and causing a fire.

Besides, inhaling the gases released by a punctured battery can be dangerous. There is no reliable way to fix a swollen battery, at least none that should be attempted by regular consumers. So the best course of action is to dispose of your battery by taking it to a battery recycling center/ collection site.

Proper Handling Of A Swollen PSP Battery

Swollen batteries are like ticking time bombs. You never know when they will reach the breaking point and cause a short, catching fire. Hence, it is not advised to throw these in your dustbin.

If possible, always take the swollen battery to an e-waste center or shop that is qualified to handle such devices. Wear gloves or use a tong while handling swollen batteries, and don’t press on them too hard. Don’t poke a hole in the battery to deflate it, because you might break the separator and cause a short circuit.

Gases emitted by a swollen battery are dangerous, so keep your face away from it and don’t inhale these gases directly. Have a non-flammable container nearby (a steel bucket filled halfway with sand is pretty good). And don’t try charging your PSP with a swollen battery.

Replacing Your Swollen PSP Battery

Once you’ve properly removed and disposed of the old swollen battery, you can install a fresh one. As I mentioned earlier, it’s important to not cheap out while purchasing a battery for your PSP. If possible, source OEM parts.

Batteries made by Sony can be found online, and they are more expensive than batteries made by 3rd parties. For the PSP-1000, you want a 1800mAh battery. If you have a PSP-2000 or PSP-3000, a 1200mAh battery is needed.

PSP Go has to be disassembled to reach the battery. For the Go, you want a 3.7V 930mAh lithium battery (it’s 3.6V for regular PSP models). For regular PSPs, you just remove the rear battery cover with your finger and install the new battery.

Sony didn’t design the PSP Go to be user-serviceable. Hence, you’ll need a Phillips #00 screwdriver to remove the entire backplate and access the battery connector. Third-party battery options for all PSP models are plentiful, but always check reviews to see if they are made well.


I hope this article helped you understand why PSP batteries swell over time, and how to properly handle these damaged units. To prevent the issue, charge your PSP before putting it into storage for months in a row. A battery that is completely discharged is likely to swell within a few months.

Hot temperatures and excess humidity accelerate the chemical process that causes this swelling. So try to store your PSP in a cool and dry environment, around 25°C is ideal. If your PSP battery is bloated, don’t attempt to recharge it and purchase a new one instead.


As long as I can remember myself I always enjoyed video games. I had amazing moments playing them and that's why I became a game developer, to create amazing experiences for the players. Read More About Me

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