WEBVTT - Batteries and Fast Recharging 0:00:04.400 --> 0:00:07.800 Welcome to tech Stuff, a production from I Heart Radio. 0:00:12.119 --> 0:00:15.080 Hey there, and welcome to tech Stuff. I'm your host, 0:00:15.240 --> 0:00:18.600 Jonathan Strickland. I'm an executive producer with I Heart Radio 0:00:18.680 --> 0:00:22.959 and I love all things tech and I end nearly 0:00:23.160 --> 0:00:26.160 every episode of tech Stuff asking y'all if there are 0:00:26.160 --> 0:00:28.880 any topics you'd like to hear me explain on the show. 0:00:29.160 --> 0:00:31.720 And recently a lot of you have been sending in requests, 0:00:31.920 --> 0:00:34.879 which is awesome, and I'm getting to those now that 0:00:35.000 --> 0:00:38.720 those tech glossary episodes are all done. And first up 0:00:39.000 --> 0:00:41.680 is a message from Brian Perez, who wants to know 0:00:41.800 --> 0:00:47.760 about fast charging technology, which is a great and legitimately 0:00:47.880 --> 0:00:52.800 confusing suggestion because there are a lot of different technologies 0:00:52.840 --> 0:00:57.480 out there. So today we're gonna talk about how batteries work, 0:00:57.720 --> 0:01:01.520 because that's important for us to understand this technology. Then 0:01:01.560 --> 0:01:05.479 we're gonna talk more about how rechargeable batteries work, because 0:01:05.480 --> 0:01:08.800 clearly that's going to be important. And then we'll talk 0:01:08.840 --> 0:01:12.119 about what makes fast charging possible and some of the 0:01:12.200 --> 0:01:15.600 different technologies that are out on the market and why 0:01:15.640 --> 0:01:18.520 it's such a mess. Uh So let's do that, and 0:01:18.560 --> 0:01:22.320 we'll start with the basics of electricity and that lovely 0:01:22.360 --> 0:01:27.319 equation that tells us that wattage that that's a measurement 0:01:27.400 --> 0:01:33.120 of power, is equal to current in ampiers times voltage 0:01:33.360 --> 0:01:36.279 or volts, And it's good to remember the difference between 0:01:36.319 --> 0:01:40.800 current and volts. Current refers to the amount of electric 0:01:41.400 --> 0:01:45.160 current moving across a circuit, and voltage is the force 0:01:45.800 --> 0:01:49.200 that drives that current. So frequently folks like me use 0:01:49.240 --> 0:01:53.280 the analogy of water pressure to describe voltage and the 0:01:53.320 --> 0:01:57.000 amount of water actually flowing through a system to describe current. 0:01:57.680 --> 0:02:00.440 Uh So, voltage is sort of the umph at which 0:02:00.480 --> 0:02:05.320 current gets pushed. We'll come back to the watch discussion 0:02:05.520 --> 0:02:08.120 towards the end of this episode, because that's really at 0:02:08.160 --> 0:02:12.600 the heart of fast charging technology. So let's talk about 0:02:12.840 --> 0:02:17.760 how batteries work in general and the evolution of the battery. Now, 0:02:17.800 --> 0:02:20.000 one thing we have to keep in mind is that 0:02:20.200 --> 0:02:26.519 batteries don't create energy. Energy can be neither created nor destroyed. 0:02:26.919 --> 0:02:32.120 Batteries store energy in the form of chemical energy. They 0:02:32.280 --> 0:02:35.640 release energy in the form of electricity. So we're really 0:02:35.680 --> 0:02:39.600 talking about converting one type of energy into another. That 0:02:39.760 --> 0:02:43.320 is possible, right. We can't create or destroy energy, but 0:02:43.400 --> 0:02:46.919 we can change it from one form to another. So 0:02:47.280 --> 0:02:51.080 that's the heart of what batteries do. Batteries go through 0:02:51.120 --> 0:02:55.320 an electro chemical reaction and through that process they release 0:02:55.480 --> 0:03:00.960 electrons i eat. Electricity. The reaction takes play, and electrons 0:03:01.040 --> 0:03:04.119 are a byproduct. They are released as part of this 0:03:04.560 --> 0:03:08.480 chemical reaction. Even when a battery isn't being used, this 0:03:08.560 --> 0:03:12.960 reaction can still occur, though typically at a very much 0:03:13.040 --> 0:03:16.520 slower rate. Right otherwise, batteries would be dead before you 0:03:16.560 --> 0:03:19.440 ever got a chance to use them, but it does happen. 0:03:19.560 --> 0:03:23.240 This is called self discharge. This is one of the 0:03:23.240 --> 0:03:26.480 factors that determines the shelf life of a battery. So 0:03:26.520 --> 0:03:29.520 if you ever look at just a long list of 0:03:29.560 --> 0:03:33.200 all the different types of batteries, you'll typically see the 0:03:33.400 --> 0:03:37.440 listed you know, average shelf life of them, and if 0:03:37.480 --> 0:03:40.600 it's a shorter shelf life, that tells you that there's 0:03:40.640 --> 0:03:44.920 a higher rate of of self discharge. Generally speaking, that's 0:03:44.960 --> 0:03:49.160 actually being a little too reductive because it also depends 0:03:49.200 --> 0:03:51.920 on the capacity of the battery, like how how much 0:03:52.040 --> 0:03:54.880 volume does the battery have, But we're not going to 0:03:55.040 --> 0:03:58.400 dive too deep into all of that. So batteries that 0:03:58.480 --> 0:04:02.120 are in hot environ ments also tend to self discharge 0:04:02.160 --> 0:04:04.320 at a faster rate than batteries that are in a 0:04:04.480 --> 0:04:07.560 colder environment, So you don't want your batteries to be 0:04:07.600 --> 0:04:10.600 in someplace that's going to be really hot. However, this 0:04:10.800 --> 0:04:13.920 also leads some people to make a decision that is 0:04:13.960 --> 0:04:16.960 not very wise. It is not a good idea to shove, 0:04:17.440 --> 0:04:21.120 you know, unused batteries in the freezer so that you 0:04:21.200 --> 0:04:25.240 can make them last longer. The lower temperatures that the 0:04:25.279 --> 0:04:30.039 batteries experience. That means that it will impede the chemical 0:04:30.120 --> 0:04:33.720 reaction when you plug it into something. So this means 0:04:33.760 --> 0:04:36.600 that a cold battery will not perform as well as 0:04:36.680 --> 0:04:40.280 a normal battery until it gets up to temperature. And 0:04:40.640 --> 0:04:42.800 when I say that the battery will eventually go dead 0:04:42.960 --> 0:04:46.480 through self discharge, often we are talking about a factor 0:04:46.480 --> 0:04:51.680 about years, right, So self discharge doesn't happen overnight. There's 0:04:51.720 --> 0:04:54.600 no reason to put batteries into the fridge or the 0:04:54.600 --> 0:04:58.280 freezer or anything like that, because you're likely going to 0:04:58.400 --> 0:05:03.240 use them before they would have self discharged anyway. Setting 0:05:03.240 --> 0:05:08.640 aside stories about you know, ancient Babylonian containers that might 0:05:08.640 --> 0:05:11.480 have been used as some sort of proto battery, possibly 0:05:11.600 --> 0:05:15.640 for the purposes of electro plating materials. The ancestor of 0:05:15.680 --> 0:05:22.200 the modern battery really took shape in sevent with Alessandro Volta, 0:05:22.320 --> 0:05:26.240 and his name gives us the word volt. More importantly, 0:05:26.560 --> 0:05:31.279 our history starts with a disagreement between two scientific thinkers, 0:05:31.920 --> 0:05:36.680 and those thinkers were Volta and Luigi Galvani. Now, Galvani 0:05:36.800 --> 0:05:39.880 had observed in the seventeen eighties that if he were 0:05:39.920 --> 0:05:43.720 to take a frog that was really most sincerely dead 0:05:44.000 --> 0:05:48.200 and expose said dead froggy's leg muscles by you know, 0:05:48.600 --> 0:05:51.760 cutting away the skin and then touching that muscle with 0:05:51.839 --> 0:05:55.080 an arc made from iron and brass, it would cause 0:05:55.120 --> 0:05:59.640 the muscle to twitch. Now, Galvani had already run experiments 0:06:00.080 --> 0:06:04.039 using things like an electrostatic generator, so a device that 0:06:04.480 --> 0:06:08.640 generates an electrostatic charge, and he knew that there was 0:06:08.680 --> 0:06:12.520 some connection between muscular movement and electricity because of this. 0:06:13.080 --> 0:06:15.320 But this was different, right because he was using what 0:06:15.440 --> 0:06:18.640 appeared to be an inert pair of metals. It was 0:06:18.680 --> 0:06:21.720 an iron embrass, and there was no electro static machine 0:06:21.760 --> 0:06:25.320 generating a charge. He wasn't even doing this during a thunderstorm. 0:06:25.360 --> 0:06:29.920 He had observed that thunderstorms could also produce electrostatic charges 0:06:29.960 --> 0:06:34.440 that could then influence experiments like these, But this was 0:06:34.480 --> 0:06:37.440 a case where neither of those things were components. So 0:06:37.480 --> 0:06:41.760 he said, the electricity must reside within the muscle itself. 0:06:41.839 --> 0:06:44.479 If it's not in the iron embrass, it's gotta be 0:06:45.240 --> 0:06:49.080 in the muscle, and Volta thought that his buddy Galvani 0:06:49.279 --> 0:06:53.000 was totally on the wrong track. Volta's assertion was that 0:06:53.080 --> 0:06:56.280 the cause of the twitching was due to the use 0:06:56.320 --> 0:06:59.240 of two different metals that were connecting to one another 0:06:59.560 --> 0:07:04.279 through the medium of a moist conductive UH substance, that 0:07:04.320 --> 0:07:07.919 being the froggy's leg muscle. So Volta decided to experiment 0:07:07.960 --> 0:07:11.320 in the field of electrochemical reactions to see if perhaps 0:07:11.360 --> 0:07:15.560 he was right and if Galvanni was wrong. So Galvanni, 0:07:15.560 --> 0:07:18.760 by the way, was totally right in that muscle movements 0:07:18.840 --> 0:07:23.400 are the result of electrochemical processes, but in this case 0:07:23.480 --> 0:07:25.720 Volta was saying, yeah, but that's not what's happening here. 0:07:26.000 --> 0:07:29.920 I don't think you're you're making the right hypothesis. So 0:07:30.000 --> 0:07:33.880 Volta created a stack of material He alternated layers of 0:07:34.000 --> 0:07:37.880 zinc UH. He then put in some cardboard that had 0:07:37.880 --> 0:07:41.240 been soaked in brine, and then he would put on 0:07:41.360 --> 0:07:44.440 layers of silver. So he kind of alternated with these, 0:07:44.760 --> 0:07:46.680 and he was able to create a kind of proto 0:07:46.840 --> 0:07:50.040 battery that we refer to with the charming name of 0:07:50.440 --> 0:07:54.880 voltaic pile. There were some pretty big limitations to this, however. 0:07:55.320 --> 0:07:57.800 The strength of this battery depended in part on the 0:07:57.880 --> 0:08:01.560 number of layers that he could build up. However, he 0:08:01.640 --> 0:08:05.600 couldn't make it too tall, because the layers on top 0:08:05.840 --> 0:08:09.160 would start to press down so hard on the layers 0:08:09.200 --> 0:08:13.600 below that the brine in that cardboard would get squeezed out, 0:08:14.280 --> 0:08:17.360 and then it would suddenly be less effective. Also, the 0:08:17.400 --> 0:08:21.520 metal would corrode fairly quickly due to the electrochemical reactions, 0:08:22.240 --> 0:08:27.120 and uh, the the byproduct would build up on those plates, 0:08:27.120 --> 0:08:32.079 and eventually they would impede the reaction from continuing, and 0:08:32.160 --> 0:08:37.600 you'd see a decrease in electrical output because of it. Now, 0:08:37.640 --> 0:08:40.439 just a few decades after Volta's work, there was an 0:08:40.440 --> 0:08:46.000 English chemist named John Frederick Danielle who made an or Daniel. 0:08:46.080 --> 0:08:47.840 I suppose it doesn't have an E at the end, 0:08:47.880 --> 0:08:50.480 so I'll say daniel it's d A N I E 0:08:50.720 --> 0:08:54.360 L l uh. He made an early battery using a 0:08:54.400 --> 0:08:58.360 plate of copper, a plate of zinc, and some gnarly chemicals. 0:08:58.800 --> 0:09:01.160 Let's see if I can paint a mental picture. So 0:09:01.200 --> 0:09:04.760 he took a big glass jar and at the bottom 0:09:04.800 --> 0:09:07.079 of the inside of this jar he put the copper plate, 0:09:07.200 --> 0:09:10.280 so the copper plates at the bottom. On top of 0:09:10.480 --> 0:09:13.880 the copper plate, he poured in a solution of copper sulfate. 0:09:14.559 --> 0:09:16.520 By the way, these days, copper sulfate is used in 0:09:16.559 --> 0:09:20.600 stuff like herbicides because it kills plants pretty darn effectively. Also, 0:09:20.640 --> 0:09:24.840 when we're talking about batteries, were often talking about chemicals 0:09:24.880 --> 0:09:29.000 that are acidic. That is pretty common. You've probably heard 0:09:29.120 --> 0:09:32.800 about battery acid and it's one of the many reasons 0:09:32.960 --> 0:09:36.280 why you don't want to mess around, you know, cutting 0:09:36.280 --> 0:09:38.880 open batteries and stuff. There are a lot of reasons 0:09:38.880 --> 0:09:41.080 for that, specifically when you get the things like lithium 0:09:41.120 --> 0:09:44.520 ion batteries and um that's one of the many ones. 0:09:44.760 --> 0:09:48.600 So then he then on top of this copper sulfate solution, 0:09:49.360 --> 0:09:53.400 he poured in a zinc sulfate solution. Now, copper sulfate 0:09:53.720 --> 0:09:57.480 has a greater density than zinc sulfate, so the copper 0:09:57.520 --> 0:10:00.400 sulfate settled down at the bottom of the jar, and 0:10:00.440 --> 0:10:03.520 the zinc sulfate floated to the top. You've probably seen 0:10:03.559 --> 0:10:05.839 like mixtures of oil and water that do this kind 0:10:05.840 --> 0:10:10.600 of thing. Daniel then suspended a zinc plate within these 0:10:10.679 --> 0:10:13.960 zinc sulfate half of the jar. So imagine like a 0:10:14.000 --> 0:10:16.600 hook that hooks over the side of the jar, and 0:10:16.760 --> 0:10:20.800 hanging from that hook is a plate of zinc held 0:10:20.840 --> 0:10:25.160 horizontal above the copper sulfate level. Right, So you've got 0:10:25.160 --> 0:10:30.600 two separate levels here, and two separate sulfates uh to 0:10:30.760 --> 0:10:34.880 each plate. He attached a conductive wire. And now we 0:10:35.000 --> 0:10:38.120 need a bit of an anatomy lesson for batteries. So 0:10:38.200 --> 0:10:42.120 let's consider your typical battery. Let's say that you just 0:10:42.200 --> 0:10:43.960 if you happen to have a battery nearby, you can 0:10:44.000 --> 0:10:46.160 even look at one and and kind of get the 0:10:46.240 --> 0:10:49.320 lay of the land. So you've got two terminals with 0:10:49.400 --> 0:10:52.439 your battery, Like if it's a double a battery, it's 0:10:52.480 --> 0:10:56.240 on either end of the battery. Right. These are the 0:10:56.240 --> 0:10:58.520 points of the batteries that connect to a circuit or 0:10:58.679 --> 0:11:01.720 or a load. This is the pathway that electrons will 0:11:01.720 --> 0:11:04.400 take where at some point along the way they will 0:11:04.440 --> 0:11:07.120 presumably do some sort of work. So you've got a 0:11:07.120 --> 0:11:11.000 positive terminal and you've got a negative terminal. You could 0:11:11.600 --> 0:11:15.120 connect these two terminals directly to each other with conductive wire, 0:11:15.200 --> 0:11:17.920 but that's not a great idea. That would lead to 0:11:17.960 --> 0:11:22.160 the battery discharging very rapidly, and for some tymes of batteries, 0:11:22.160 --> 0:11:24.679 that could be dangerous as the battery will heat up 0:11:24.720 --> 0:11:30.080 from the rapid electrochemical reaction, potentially leading to combustion or explosion. 0:11:30.280 --> 0:11:32.960 So not a good idea to do this. Attached to 0:11:33.000 --> 0:11:37.480 the positive terminal inside the battery is the cathode. Connected 0:11:37.520 --> 0:11:42.000 to the negative terminal inside the battery is the annode. Together, 0:11:42.280 --> 0:11:46.360 these are the electrodes of the battery. There's a separator 0:11:46.520 --> 0:11:49.440 that keeps those two electrodes from touching. Otherwise we would 0:11:49.480 --> 0:11:51.840 have a very similar situation to what I was talking 0:11:51.840 --> 0:11:54.520 about before, where you connect the two terminals with a 0:11:54.520 --> 0:11:57.439 conductive wire, only in this case it would be internal 0:11:57.520 --> 0:12:00.480 inside the battery as opposed to connect did through an 0:12:00.480 --> 0:12:05.360 external wire. The separator does allow an electric charge to 0:12:05.440 --> 0:12:08.720 flow between the two electrodes. Uh. There's also a medium 0:12:08.760 --> 0:12:12.920 called the electrolyte that facilitates the flow of electric charge. 0:12:13.240 --> 0:12:16.760 So during discharge, The anode reacts with the electrolyte and 0:12:16.840 --> 0:12:23.280 experiences and oxidation reaction. Ions that is, atoms or molecules 0:12:23.320 --> 0:12:27.800 that carry an electric charge from the electrolyte will react 0:12:27.840 --> 0:12:31.280 with the anode and that produces a new compound between 0:12:31.320 --> 0:12:34.960 the two and in this process also releases electrons. So 0:12:35.000 --> 0:12:38.840 now we've got our supply of electrons popping over onto 0:12:38.840 --> 0:12:42.280 the cathode side. The cathode goes through a reduction reaction 0:12:42.679 --> 0:12:47.120 in which ions, electrons, and the cathode begin to form compounds. 0:12:47.520 --> 0:12:51.040 This process takes in electrons while the process that the 0:12:51.080 --> 0:12:54.719 anode generates electrons, but the separator keeps the electrons from 0:12:54.760 --> 0:12:57.480 just rushing over from one side to the other. Right, 0:12:57.960 --> 0:13:00.080 you would think, all right, if we've gotten excess of 0:13:00.120 --> 0:13:04.240 electrons and like charge repels like, then the electrons don't 0:13:04.280 --> 0:13:05.880 want to be next to each other, right, they'd rather 0:13:05.880 --> 0:13:08.640 get to the other side, especially as that side grows 0:13:08.679 --> 0:13:13.520 more positive because the electrons are negative and opposite charges attract. 0:13:14.320 --> 0:13:17.400 But the separator prevents the electrons from doing this. They 0:13:17.480 --> 0:13:21.520 can't get to that side unless you open a pathway 0:13:21.559 --> 0:13:24.640 for them. That pathway is the circuit. So when you 0:13:24.720 --> 0:13:27.680 open up a circuit. You create a circuit that goes 0:13:27.760 --> 0:13:30.920 connects between these two electrodes. Now the electrons have a 0:13:30.920 --> 0:13:33.920 way to get away from the negatively charged side of 0:13:33.920 --> 0:13:36.920 the battery and head to the positive charged side of 0:13:36.960 --> 0:13:39.160 the battery, and they will do that even if it 0:13:39.160 --> 0:13:41.560 means they have to do some work along the way. 0:13:41.800 --> 0:13:45.440 Thus we have batteries. So with Daniels battery, which we 0:13:45.520 --> 0:13:48.720 call the Daniel cell, the wire connected to the zinc 0:13:48.760 --> 0:13:51.679 plate served as the negative terminal. The wire attached to 0:13:51.679 --> 0:13:53.440 the copper plate at the bottom of the jar was 0:13:53.480 --> 0:13:56.800 the positive terminal. And the cell worked really well. But 0:13:57.000 --> 0:14:01.360 because we're talking about liquid components here, it couldn't really 0:14:01.400 --> 0:14:04.280 be used in any sort of application that the thing 0:14:04.280 --> 0:14:07.480 would be moved around because it would just be slashing everywhere, right, 0:14:07.480 --> 0:14:11.160 So it had to be stationary, and that really limited 0:14:11.640 --> 0:14:14.480 what you could do with this kind of battery. A 0:14:14.480 --> 0:14:17.600 few decades later brings us up to the eighteen sixties. 0:14:17.960 --> 0:14:22.160 That's when George Leshan switched things up by making a 0:14:22.240 --> 0:14:26.200 battery out of a porous pot. He took some crushed 0:14:26.320 --> 0:14:29.760 manganese dioxide with a little bit of carbon in it, 0:14:30.160 --> 0:14:32.920 and he used that as the cathode. He packed that 0:14:33.040 --> 0:14:37.000 onto the inside of the porous pot. The annode was 0:14:37.160 --> 0:14:40.600 a zinc rod that was actually kept separate from the pot. 0:14:40.680 --> 0:14:42.880 So you had a pot on the inside of which 0:14:43.080 --> 0:14:46.600 was this mixture of manganese dioxide and carbon, and then 0:14:46.640 --> 0:14:50.080 you have this zinc rod. Then he leant put both 0:14:50.120 --> 0:14:53.560 the pot and the zinc rod into another container filled 0:14:53.560 --> 0:14:58.640 with ammonium chloride that acted as the electrolyte. Now, this 0:14:59.280 --> 0:15:03.840 solution of amonium chloride seeped through the porous pot to 0:15:03.920 --> 0:15:06.920 make contact with the cathode and that allowed the electrochemical 0:15:06.960 --> 0:15:10.360 process to begin and the carbon rod that would also 0:15:10.400 --> 0:15:15.640 be inserted into this Uh, this pot acted as a 0:15:15.680 --> 0:15:19.080 collector for the electrons. So that's what you would use 0:15:19.160 --> 0:15:23.560 to you know, direct the electrons outward to whatever circuit. 0:15:23.840 --> 0:15:26.840 This type of battery saw widespread use in telegraph stations, 0:15:26.880 --> 0:15:30.920 but still relied on a liquid electrolyte, and UH that 0:15:31.000 --> 0:15:34.120 really made it unsuitable for stuff what moved around a lot, 0:15:34.200 --> 0:15:38.480 so still not ideal. We would see all that change 0:15:38.680 --> 0:15:43.000 thanks to the work of inventor Carl Gossner from Germany. 0:15:43.400 --> 0:15:45.440 I originally put in my notes that he was a 0:15:45.440 --> 0:15:49.560 German inventor, But now that I read that, it sounds 0:15:49.560 --> 0:15:52.280 like he invented Germans, and I'm pretty sure they were 0:15:52.320 --> 0:15:57.480 around before him. Anyway, Gassner made several improvements to batteries, 0:15:57.720 --> 0:15:59.760 and that meant that they would be practical in many 0:15:59.840 --> 0:16:02.720 of our applications. For one thing, Gastner had the bright 0:16:02.760 --> 0:16:05.920 idea to use zinc as the container material for the 0:16:05.920 --> 0:16:08.840 battery itself. So the body of the battery was made 0:16:08.880 --> 0:16:12.880 out of zinc and it also served as the negative electrode, 0:16:12.920 --> 0:16:15.120 so it was doing double duty. It was the container 0:16:15.760 --> 0:16:18.440 and the negative electrode, so the actual body of the 0:16:18.440 --> 0:16:20.920 battery served as one of the two electrodes the anode. 0:16:21.040 --> 0:16:24.160 In case you're trying to keep these things straight. Inside 0:16:24.160 --> 0:16:27.720 the battery, he put in a folded paper sack which 0:16:27.720 --> 0:16:30.680 served as the separator, which kept the interior of the 0:16:30.760 --> 0:16:34.240 zinc case separate from the electrolyte. For the cathode, he 0:16:34.320 --> 0:16:37.040 used a mixture of manganese ox side and in the 0:16:37.040 --> 0:16:39.800 middle of this he suspended a carbon rod, which again 0:16:39.840 --> 0:16:43.600 acted as the electron collector. And later he would add 0:16:43.760 --> 0:16:47.640 zinc chloride to the electrolyte because it reduced the rate 0:16:47.680 --> 0:16:51.120 at which the electro light would corrode the zinc uh 0:16:51.360 --> 0:16:54.000 of the case. It would It would then extend the 0:16:54.000 --> 0:16:59.080 batteries useful life by slowing down that that process. But 0:16:59.160 --> 0:17:02.160 the most important part of this invention was that Gasner's 0:17:02.160 --> 0:17:05.320 battery is what we call a dry cell battery. It 0:17:05.440 --> 0:17:09.160 was not full of sloshy liquid. Even though the electrolyte 0:17:09.200 --> 0:17:12.040 was sort of a jelly liquid e kind of thing, 0:17:12.440 --> 0:17:13.960 the rest of it was all dry. I meant that 0:17:13.960 --> 0:17:16.439 you didn't have to worry about the battery components slash 0:17:16.480 --> 0:17:18.880 galt all over the place, admit that you could invert 0:17:18.960 --> 0:17:20.639 it and it would still work. It opened up a 0:17:20.640 --> 0:17:24.080 lot of applications for batteries. In the eighteen nineties, the 0:17:24.160 --> 0:17:28.840 National Carbon Company, a US based organization, developed the Columbia 0:17:28.960 --> 0:17:34.160 dry cell battery, which was another improvement. They first started 0:17:34.240 --> 0:17:37.800 making La Sanche batteries in the eighteen nineties, but again 0:17:37.840 --> 0:17:40.879 those were wet cell batteries. An engineer at the company 0:17:40.960 --> 0:17:44.440 named E. M. Jewitt created a one point five volt 0:17:44.600 --> 0:17:47.359 dry cell battery and got the blessing from the company 0:17:47.400 --> 0:17:50.080 to make a commercial version that they could actually sell. 0:17:50.560 --> 0:17:54.000 So in eighteen nine six NCC began selling a one 0:17:54.040 --> 0:17:58.600 and a half volt six inch long dry cell battery. Interestingly, 0:17:59.119 --> 0:18:02.160 the National Car been Company would buy a fifty steak 0:18:02.200 --> 0:18:07.040 in another company called the American Electrical Novelty and Manufacturing Company. 0:18:07.560 --> 0:18:10.400 The battery making part of that company joined in CC 0:18:10.640 --> 0:18:14.160 and together they became known as ever Ready, and much 0:18:14.240 --> 0:18:17.880 later that company would change its name to Energizer, So 0:18:18.080 --> 0:18:19.920 that one dates all the way back to the early 0:18:20.000 --> 0:18:23.520 nineteen hundreds. All the batteries I mentioned so far are 0:18:23.560 --> 0:18:27.960 what we call primary batteries. So a primary battery is 0:18:28.000 --> 0:18:31.760 a one use battery. That means once the battery goes dead, 0:18:32.520 --> 0:18:36.760 it's really most sincerely dead. It's not coming back because 0:18:37.080 --> 0:18:42.080 we're talking about a different chemical component reacting with another 0:18:42.359 --> 0:18:46.080 chemical component to produce electricity, and then you get by 0:18:46.119 --> 0:18:49.399 products as well, and you eventually run low enough on 0:18:49.520 --> 0:18:53.680 those initial chemical components that you're not getting enough juice 0:18:53.720 --> 0:18:57.520 and there's no way to reverse that process. Right once 0:18:57.560 --> 0:19:02.400 it turns into the byproducts, the battery has become a nert. 0:19:03.320 --> 0:19:05.720 Now a few things that can that can happen to 0:19:05.800 --> 0:19:09.000 make a battery less effective. One is that, as I mentioned, 0:19:09.320 --> 0:19:12.440 you could have your chemical agents depleted in the battery, 0:19:12.760 --> 0:19:14.800 So what you've got now is essentially a container just 0:19:14.840 --> 0:19:18.639 filled with useless goop as a result of all these 0:19:18.680 --> 0:19:22.640 electrochemical reactions taking place. Another is that whatever you're using 0:19:22.640 --> 0:19:26.840 as an electron collector might get covered in deposits, and 0:19:26.920 --> 0:19:30.480 that blocks the collector's ability to collect electrons. And so 0:19:31.000 --> 0:19:34.000 you might still have some viable juice in the battery, 0:19:34.080 --> 0:19:38.880 but because of this corrosion coding elements inside the battery, 0:19:39.119 --> 0:19:43.800 it's not able to have that that process go effectively. 0:19:44.400 --> 0:19:47.440 Corrosion is also an issue as well for the electrodes. 0:19:47.760 --> 0:19:50.520 If you've ever had an old battery and something and 0:19:50.520 --> 0:19:53.240 you've just seen this gross kind of build up on it, 0:19:53.400 --> 0:19:56.600 that's often the corrosion I'm talking about. And all of 0:19:56.600 --> 0:19:59.760 these things lead to a batteries and ability to produce current. 0:20:00.560 --> 0:20:04.120 With primary batteries, there's really no way to reverse this process. 0:20:04.160 --> 0:20:07.040 The electrochemical reactions will stop, and then you've got to 0:20:07.040 --> 0:20:11.320 toss the battery. Primary batteries tend to be relatively inexpensive. 0:20:11.640 --> 0:20:14.680 They also tend to have a fairly long shelf life, 0:20:15.000 --> 0:20:18.040 but they're also wasteful. When we come back, we'll talk 0:20:18.040 --> 0:20:23.280 about secondary batteries, also known as rechargeable batteries. But first, 0:20:23.359 --> 0:20:34.120 let's take a quick break. When I was talking earlier 0:20:34.160 --> 0:20:37.199 about the development of the battery, the last inventor I 0:20:37.240 --> 0:20:40.920 mentioned was Carl Gassner, who invented the dry cell battery, 0:20:41.040 --> 0:20:46.159 which was in but the rechargeable battery actually predates the 0:20:46.280 --> 0:20:49.320 dry cell battery, and the person who generally gets the 0:20:49.320 --> 0:20:55.359 credit for inventing them is Gaston Plante. No one invents 0:20:55.440 --> 0:20:59.880 like Gaston or imprints like guests. Okay, I'll never mind. 0:21:00.080 --> 0:21:03.800 In eighteen fifty nine, he created a lead acid battery 0:21:03.840 --> 0:21:07.320 that you could actually recharge his batteries and ode was 0:21:07.400 --> 0:21:10.239 made of a sheet of lead, and he used a 0:21:10.280 --> 0:21:13.560 sheet of lead dioxide for the cathode, and he placed 0:21:13.600 --> 0:21:17.160 a linen cloth between those two sheets. Then he rolled 0:21:17.280 --> 0:21:21.840 this into a cone shaped spiral. He immersed this cone 0:21:21.920 --> 0:21:25.600 in a solution of sulfuric acid, which is pretty dangerous stuff, 0:21:25.960 --> 0:21:29.399 and the chemical reaction that resulted released electrons and boom, 0:21:29.400 --> 0:21:33.040 you get yourself a battery. Gaston discovered that if he 0:21:33.160 --> 0:21:36.800 applied a charge to this battery so that current flowed 0:21:36.880 --> 0:21:40.680 into the battery, it would actually reverse the electrochemical reaction 0:21:40.840 --> 0:21:44.480 that produced the electrons. This battery then had a way 0:21:44.520 --> 0:21:48.680 to discharge and then recharge. In eighteen sixty he presented 0:21:48.720 --> 0:21:52.439 a nine cell battery to the French Academy of Sciences, 0:21:52.440 --> 0:21:56.840 and his peer Camille Alphonse for continued to work on 0:21:56.880 --> 0:21:59.840 the invention and saw it actually become a commercial product. 0:22:00.160 --> 0:22:03.639 Camille would later make improvements to this battery, including a 0:22:03.720 --> 0:22:07.640 process that would increase the battery's capacity for storing electricity. 0:22:07.960 --> 0:22:11.560 And we still use lead acid batteries today. It's the 0:22:11.600 --> 0:22:14.520 type of battery you find in your typical internal combustion 0:22:14.600 --> 0:22:17.520 engine vehicle. So your typical car that has an internal 0:22:17.520 --> 0:22:20.840 combustion engine also has a lead acid battery. Now, I 0:22:20.880 --> 0:22:24.679 mentioned that Gaston created a nine cell battery, and that 0:22:24.840 --> 0:22:27.080 is something that we should chat about for just a moment. 0:22:27.680 --> 0:22:31.960 Some batteries, like car batteries, consist of multiple cells that 0:22:32.040 --> 0:22:35.240 connect to one another within the battery itself. So a 0:22:35.280 --> 0:22:39.960 typical car battery would have six cells connected in series. 0:22:40.400 --> 0:22:44.119 If you connect batteries in series, you increase the voltage 0:22:44.440 --> 0:22:48.600 that those batteries produce. Now, remember, voltage is kind of 0:22:48.640 --> 0:22:52.720 like pressure. That's how much umph is behind an electrical current, 0:22:53.119 --> 0:22:56.120 but it's not a measure of the amount of current itself. 0:22:56.160 --> 0:22:59.760 So you're not increasing the current by adding batteries or 0:23:00.000 --> 0:23:04.119 mattery cells in series. You're increasing the voltage. If you 0:23:04.119 --> 0:23:07.200 add them in parallel, it's different. But we're talking about 0:23:07.200 --> 0:23:10.399 in series one after the other. So your typical lead 0:23:10.480 --> 0:23:15.119 acid battery has cells that individually have a voltage of 0:23:15.200 --> 0:23:18.520 two volts, but because they are connected in series, the 0:23:18.520 --> 0:23:22.240 battery overall has a voltage of twelve volts. Right, you've 0:23:22.240 --> 0:23:25.680 got six cells each two volts. You've got them in series, 0:23:25.920 --> 0:23:29.000 so it multiplies the voltage to twelve. Most of your 0:23:29.000 --> 0:23:32.800 typical household batteries, like double as, triple AS, C and 0:23:32.960 --> 0:23:35.560 D batteries, those typically come in at one and a 0:23:35.600 --> 0:23:38.720 half volts. But again, if you connect them in series, 0:23:38.800 --> 0:23:42.159 you get more voltage. So a flashlight that has two 0:23:42.440 --> 0:23:46.600 batteries connected in series is actually relying on three volts 0:23:47.000 --> 0:23:50.359 for the voltage. Another thing we should touch on is 0:23:50.400 --> 0:23:55.240 that because batteries convert chemical energy into electrical energy, there's 0:23:55.280 --> 0:23:58.880 a fundamental limit as to how much juice a battery 0:23:58.920 --> 0:24:02.400 can hold. That doesn't mean all batteries are equal. Depending 0:24:02.400 --> 0:24:06.280 on the materials used to create that electrochemical reaction, you 0:24:06.320 --> 0:24:10.360 can get more efficient and energy dense batteries. For example, 0:24:10.520 --> 0:24:14.520 lead acid batteries don't really have great energy density, which 0:24:14.560 --> 0:24:17.520 you typically measure either by comparing how much energy the 0:24:17.560 --> 0:24:22.160 battery can store compared to that batteries mass, or how 0:24:22.200 --> 0:24:25.400 much energy it can store compared to that batteries volume. 0:24:25.600 --> 0:24:29.160 There are two different ways of looking at it. Alkaline batteries, 0:24:29.200 --> 0:24:31.560 which make up a lot of the typical batteries we 0:24:31.640 --> 0:24:35.760 use today, the non rechargeable primary batteries that we use today, 0:24:36.000 --> 0:24:40.520 those are better from an energy density metric, meaning, based 0:24:40.560 --> 0:24:45.040 on that batteries mass or volume, it can hold more 0:24:45.200 --> 0:24:47.879 energy than a lead acid battery. But we also have 0:24:47.920 --> 0:24:49.760 to keep in mind that these are much smaller than 0:24:49.840 --> 0:24:54.000 lead acid batteries. The batteries power density and energy density 0:24:54.359 --> 0:24:56.800