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Figure 5.1 GM’s original EV1 used lead-acid batteries and achieved a range of 75 to 90 miles between recharges. Figure 5.2 Up to 97% of all lead-acid batteries are recycled.
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Figure 5.1 GM’s original EV1 used lead-acid batteries and achieved a range of 75 to 90 miles between recharges.
Figure 5.2 Up to 97% of all lead-acid batteries are recycled.
Figure 5.3 EV and HEV vehicles require batteries with a high specific energy (to maximize range) and high cycle life. (Courtesy of University of Toyota and Toyota Motor Sales, U.S.A., Inc.)
Figure 5.4 Interior of a NiMH battery. NiMH batteries are known as alkaline batteries because of the alkaline nature of their electrolyte.
Figure 5.5 Construction of a cylindrical lithium-ion cell. Note the pressure relief valve and exhaust gas hole that will relieve internal battery pressure if it gets too hot.
Figure 5.6 One advantage of a lithium-ion cell is that it produces 3.6 volts,whereas an NiMH cell only produces 1.2 volts.
Figure 5.7 Zinc-air batteries are recharged by replacing the zinc anodes. These batteries are also considered to be a form of fuel cell, because the positive electrode is oxygen taken from atmospheric air.
Figure 5.8 Sodium-metal-chloride batteries are also known as ZEBRA batteries. These batteries are lightweight (40% of the weight of leadacid) and have a high energy density.
Figure 5.9 The high-voltage battery and motor controls are located behind the rear passenger’s seat in a Honda Civic.
Figure 5.10 A 9-volt battery is made up of six 1.5-volt cells connected in series.
Figure 5.11 Toyota’s original Prius had a high-voltage battery pack with a total of 38 battery modules connected in series. Each module was rated at 7.2 volts, making 7.2 × 38 = 274 volts of battery output.
Figure 5.12 A NiMH cell. The unique element in a nickel-metal hydride cell is the negative electrode. Note that the electrolyte does not enter into the chemical reaction and is able to maintain a constant conductivity regardless of the state of charge of the cell.
Figure 5.13 Chemical reactions inside a NiMH cell. Charging and discharging both involve an exchange of hydrogen ions (protons) between the two electrodes.
Figure 5.14 A cylindrical NiMH cell. Some HEV high-voltage battery packs are made up of many cylindrical NiMH cells connected in series.
Figure 5.15 A prismatic NiMH cell.Prismatic cells are built with flat plates and separators similar to conventional lead-acid batteries.
Figure 5.16 Cylindrical NiMH cells from a Honda HV battery pack. Note that several of these cells will be connected in series to form one battery module.
Figure 5.17 A prismatic NiMH module (made up of six cells connected in a series) from a Toyota Prius HV battery pack.The battery posts are located on the left and right sides of the module. A self-resealing vent is located on the top right for venting hydrogen gas if the module overheats.
Figure 5.18 The battery cooling system for a Toyota hybrid SUV.All production hybrid HV battery packs are air cooled. Note the air intake vents located under the seats.
Figure 5.19 The HV battery cooling system from a Ford Escape Hybrid. This design can use either recirculated air or fresh air to cool the HV battery pack, then increases cooling with a separate zone in the A/C system when necessary.
Figure 5.20 The HV battery pack’s SOC is maintained in a relatively narrow range to prevent overheating and maximize service life.
Figure 5.21 Appropriate personal protective equipment (PPE) must be worn whenever working on or around a hybrid vehicle’s HV system.
Figure 5.22 A battery service warning label from a Honda hybridelectric vehicle.
Figure 5.23 Hybrid electric vehicles use a 12-volt lead-acid auxiliary battery located either in the trunk or the ICE compartment.
Figure 5.24 Chemical changes inside a lead-acid battery as it discharges. During this process, the positive and negative electrodes are becoming more similar (PbSO4) and the electrolyte is increasing its water content.
Figure 5.25 The charging process in a lead-acid battery. The negative and positive electrodes are being restored and the sulfuric acid content of the electrolyte is increasing.
Figure 5.26 Lead-acid battery plates are made with active material formed onto a grid made of a lead-calcium or lead-antimony alloy.
Figure 5.27 A battery cell is constructed of a group of negative plates, a group of positive plates, and separators between each of the plates. Separators are often made of porous polyethylene, which allows electrolyte to move freely between the plates.
Figure 5.28 Cutaway view of a maintenance-free battery showing the cell partitions, plate straps, and cell connectors. Note that the battery charge indicator only measures one cell.
Figure 5.29 Battery label with ratings and load test amperage. The cranking ampere (CA) rating is always higher than the CCA rating, as it is measured at 32°F instead of 0°F.
Figure 5.30 Procedure for jump starting a disabled vehicle.The final connection (step 4) is made away from the battery on the stalled vehicle to prevent a spark from causing a battery explosion.
Figure 5.31 A dead auxiliary battery on a 2004 Toyota Prius can be jump started using the special connector located on the driver’s side of the ICE compartment.
Figure 5.32 If a battery does not have its own handle, a special lifting device should be used. This tool attaches to the battery posts and makes it easy to lift a battery from its mounting bracket.
Figure 5.33 Some battery hold-downs are designed to hold the battery at the bottom of its case.This can help prevent case damage, as it is unlikely that this mount could be overtightened.
Figure 5.34 A battery cell should only be topped off with distilled water after its initial acid fill. Be careful not to overfill the cells!
Figure 5.35 Cleaning a battery top with baking soda and water will neutralize any accumulated acid. A dirty battery top can cause battery cycling, which will shorten its service life.
Figure 5.36 A battery post reamer is used to clean up batteries and terminal ends that have seen severe service.Be careful to not remove too much material from the soft lead battery posts! Note that one end is used to service the negative post, while the other is for servicing the positive post.
Figure 5.37 A battery brush is often all that is needed to clean up the battery posts and the cable ends. A simple cleaning can often solve a slowcranking concern by minimizing voltage drop in the battery cable connections.
Figure 5.38 A refractometer is an accurate and versatile tool. Besides measuring battery SOC, it can also measure freeze protection of ethylene glycol and propylene glycol coolants.
Figure 5.39 Some battery manufacturers use a state-of-charge indicator with a two-ball system. This gives a broader range of readings than an indicator that uses only one green ball.
Figure 5.40 A battery load tester. A battery should be at least 75% charged before load testing it. The large knob on the right is turned CW to increase the battery load while monitoring voltage and amperage with the readouts.
Figure 5.41 Printout of the results of a battery diagnostic test. This test equipment measures the internal impedance of the battery to help determine battery condition.
Figure 5.42 Conductance testing of a lead-acid battery. An AC voltage signal is sent into the battery and the current response signal from the battery is measured. The test equipment is programmed with reference values that are used to determine the condition of the battery. (Courtesy of Midtronics, Inc. www.midtronics.com)
Figure 5.43 A battery conductance tester. This device can determine battery condition without placing a high current load on the battery. It is also capable of testing the vehicle’s charging system for proper operation.
Figure 5.44 The General Motors parallel hybrid truck uses three VRLA batteries (located under the vehicle’s rear seat) for the 42-volt system.
Figure 5.45 Many absorbed glass mat (AGM) batteries are built with flat plates, as in flooded-cell lead-acid batteries. AGM batteries are a recombinant design and do not emit gases unless they are overheated.
Figure 5.46 A cutaway view of an absorbed glass mat (AGM) battery with cylindrical cells. AGM batteries are a type of valve-regulated lead-acid (VRLA) battery. Note the pressure relief valves located in the top of the battery case.
Figure 5.47 Pressure relief valve from a VRLA battery. This valve stays closed during normal operating conditions and prevents gases from entering or leaving the battery case.
Figure 5.48 Newer battery testing and charging equipment will often have a separate menu for AGM batteries.
Figure 5.49 This battery charger is made specifically for charging the AGM batteries used in Toyota HEVs. AGM batteries can be charged using higher current than conventional flooded-type lead-acid batteries.
