【正文】 asurement by battery discharge。四、本次設(shè)計預計達到的效果設(shè)計出一個以單片機為核心的鉛酸蓄電池容量測試系統(tǒng)，通過放電可測試其容量，并且實時顯示電池電壓與容量，測量結(jié)束后有報警提示。它是模擬啟動機啟動時的負載，測出蓄電池在大電流放電時的端電壓，根據(jù)端電壓變化來判定蓄電池的技術(shù)狀態(tài)。鉛酸蓄電池行業(yè)大有可為。第5周~第8周 繪制原理圖，制作板圖。三、主要技術(shù)指標放電電流為3~。 軟件編程。鉛酸蓄電池方面的資料。近年來，鉛酸蓄電池技術(shù)不斷發(fā)展，產(chǎn)品日臻成熟。此方法可以實現(xiàn)電池容量的直接顯示，被普遍用在電池監(jiān)測技術(shù)中。過程繁瑣，所以這種方法用得較少。實時測量并顯示電壓。隨著鉛酸蓄電池的廣泛應用，如何精確檢測蓄電池容量成為廣大用戶極為關(guān)注的問題。研制蓄電池容量檢測系統(tǒng)很有必要。(3)目前，核對放電只能測試整組電池容量，不能測試每一節(jié)單體電池容量，以容量最低的一節(jié)作為整組容量，而其他部分電池由于放電深度不夠，其劣化或落后程度還不能完全充分暴露出來。對于電池組采用1%～5%C的淺度放電；機房可以沒有備用電池組。同時測試要求較高，測試情況還不是很理想，尤其是容量測試準確度較低。(2)不同型號的儀表測量結(jié)果的差異性較大，由于各種交流法測量儀的測量頻率(15Hz～1000Hz)、測量方法(相位差法、有效值法、調(diào)制解調(diào)法、比較法等等)和測量電流(1A～10A)相差較大，讓使用不同的測量儀對于同一塊電池的測量結(jié)果相差較大，有時相差一倍。 快速容量測試技術(shù)的難點分析針對目前的實際情況，就蓄電池制造廠家、蓄電池測試技術(shù)研究機構(gòu)，以及廣大蓄電池維護人員而言，都在積極探索一種快速、準確、可靠、安全的蓄電池測試技術(shù)。對于蓄電池的設(shè)計和制造者同樣如此。而且，對于蓄電池組，使用時間越長，蓄電池個體之間的差異性和離散性越大，會出現(xiàn)兩極分化。 論文研究內(nèi)容及創(chuàng)新點主要研究利用單片機AT89C51設(shè)計一個蓄電池容量測量系統(tǒng)。 PbSO4 PbO2 + 2H2SO4 + Pb (充電反應) (硫酸鉛) (水) (硫酸鉛) 放電中的化學變化蓄電池連接外部電路放電時，稀硫酸即會與陰、陽極板上的活性物質(zhì)產(chǎn)生反應，生成新化合物(硫酸鉛)。 蓄電池之容量表示在容量試驗中，放電率與容量的關(guān)系如下： 5HR....3HR....1HR....嚴禁到達上述電壓時還繼續(xù)放電，放電愈深，電瓶內(nèi)溫會升高，則活性物質(zhì)劣化愈嚴重，進而縮短蓄電池壽命。 放電量與壽命每日反復充放電以供使用時，則電池壽命將會因放電量的深淺，而受到影響。放電時的溫度高，會提高充電完成時溫度，因此，將放電終了時的溫度控制在40℃以下為最理想。影響電池容量的因素很多，大致可以分為兩類：一是生產(chǎn)工藝方面的因素，包括活性物質(zhì)量、極板厚度、活性物質(zhì)孔率、活性物質(zhì)的真實表面積、極板的中心距、活性物質(zhì)的組成；二是使用時的因素，包括放電的電流密度、放電的終止電壓、電解液的溫度和電解液的密度。這兩種方式都相當于擴大了電解液擴散的表面積，如果把極板變薄，則相當于減小了擴散的厚度。因此極板孔率應在極板生產(chǎn)時合理選擇工藝過程，并且要嚴格控制過程保障能力，以生產(chǎn)出適合不同使用條件要求的最佳孔率的極板。并且鉛酸蓄電池活性物質(zhì)的粒子都很小，因此它們做出的極板的真實表面積要比極板的表觀表面積大幾百到幾千倍。大家都知道，極板中活性物質(zhì)孔內(nèi)的酸液量遠遠不夠活性物質(zhì)電化學反應的需要，據(jù)報道鉛酸電池極板中的酸液量僅夠活性物質(zhì)總量的10%參加電化學反應。這種鹽層雖然也遮蓋了電極表面，但是硫酸電解液仍然可以通過它的孔隙擴散到極板深處與活性物質(zhì)接觸、反應，當然能夠放出較多的容量。而大電流放電時，電壓沒有平坦部分，這時主要是擴散跟不上，形成的PbSO4較細，再充電時容易還原成金屬鉛，所以終止電壓可以定得高些。雖然低密度的電解液會對電池容量產(chǎn)生不利的影響，但是電解液密度也不能太高，如果電解液密度超過一定限度時，電解液的固有電阻增加，粘度變大，同時電池的自放電也增大，對電池容量反而不利。由于將多功能8位CPU和閃爍存儲器組合在單個芯片中，ATMEL的AT89C51是一種高效微控制器，AT89C2051是它的一種精簡版本。三級程序存儲器鎖定GND：接地。 P2口：P2口為一個內(nèi)部上拉電阻的8位雙向I/O口，P2口緩沖器可接收，輸出4個TTL門電流，當P2口被寫“1”時，其管腳被內(nèi)部上拉電阻拉高，且作為輸入。作為輸入，由于外部下拉為低電平，P3口將輸出電流(ILL)這是由于上拉的緣故。 在平時，ALE端以不變的頻率周期輸出正脈沖信號，此頻率為振蕩器頻率的1/6。注意加密方式1時，將內(nèi)部鎖定為RESET；當端保持高電平時，此間為內(nèi)部程序存儲器。輸入至內(nèi)部時鐘信號要通過一個二分頻觸發(fā)器，因此對外部時鐘信號的脈寬無任何要求，但必須保證脈沖的高低電平要求的寬度。采用外部時鐘的電路如圖31右圖所示。而蓄電池容量檢測需要對蓄電池進行恒流放電，因此在電流采樣電路中加入了恒流放電裝置，；由繼電器控制放電電路的通斷，繼電器的選取應符合大電流的要求。電壓隨著放電時間的延長而減小。，取RL=2Ω。 設(shè)計方案圖43為89C51單片機和三位共陰極顯示器的接口電路。 (3)轉(zhuǎn)換時間為100μs。21～28：8位數(shù)字量輸出端。要求時鐘頻率范圍是101280kHz。直到A/D轉(zhuǎn)換完成，EOC變?yōu)楦唠娖?，指示A/D轉(zhuǎn)換結(jié)束，結(jié)果數(shù)據(jù)已存入鎖存器，這個信號可用作中斷申請。AT89C51單片機的時鐘頻率是6MHz，則ALE端輸出信號的頻率為1MHz，符合ADC0809對時鐘頻率的要求。 容量蓄電池作為備用電源廣泛用于電力、通訊、電子設(shè)備等行業(yè)。當=36000時，83H為1，然后82H，83H的數(shù)據(jù)清零。(4)啟動A/D轉(zhuǎn)換。選通通道0 SETB MOV DPTR,A 。數(shù)字顯示子程序：。顯示碼填入顯示緩沖72HMOV A,53H MOV DPTR,LEDMAP MOVC A,A+DPTR 。延時子程序 MOV R7,0DELAYLOOP: DJNZ R7,DELAYLOOPDJNZ R6,DELAYLOOPRET第6章 結(jié)論與展望本設(shè)計采用AT89C51單片機為核心，使系統(tǒng)呈現(xiàn)單片化結(jié)構(gòu)。對它進行快速準確的容量測試是非常困難的。謝謝你們！附 錄附錄A：英文原文：LEAD ACID BATTERIESHow is it made and how does it work ?The lead acid battery is made up of a series of identical cells each containing sets of positive and negative plates.In semi traction cells flat plate construction is used. Each positive plate is a cast metallic frame which contains the lead dioxide active material. The negative plates contain spongy lead active material. Both plates usually have the same surface areas.In practice a typical cell is constructed with many more plates than just two in order to get the required current output. All positive plates are connected together as are all the negatives. Because each positive plate is always positioned between two negative plates, there is always one or more negative plate than positives.The resultant voltage of lead acid cell is normally 2 volts In order to achieve the voltage required for the application each cell is then connected in series by substantial metal straps to form a battery. In a typical monoblock battery, such as that used in a car for starting, the voltage required is 12 volts, achieved by connecting six cells together in series and enclosing them in one plastic box. Leisure batteries where a sustained current requirement is needed and a deep cycle, the ability to be discharged to 90%, have a different makeup to that of a traction battery that is used in a car.The cell containing the plates is filled with an electrolyte made up of sulphuric acid and distilled water with a specific gravity of at 60deg F ( C). Sulphuric acid is a very active pound of hydrogen and sulphur and oxygen atoms. Sulphuric acid is a very reactive substance and because of its instability it is able to distribute itself very evenly throughout the electrolyte in the battery. Over time, this action ensures that an even reaction can occur between all the plates. the lead dioxide at the positive plates turns the surface of both plates into lead sulphate. As this process occurs the hydrogen within the acid reacts with the oxygen within the lead dioxide to form water. The net result of all this reaction is that the positive plate gives up electrons and the negative plate gains them in equal numbers, thereby creating a potential difference between the two plates. Care and Maintenance of Flooded Lead Acid BatteriesThe most important aspects of care for these and all other types of batteries concern both charge and discharge as well as the mechanical treatment of the batteries . keeping them topped up with water etc.It is important to consider that lead acid (pb) batteries are, as we have seen above, quite delicate chemical factories.DischargeLead acid batteries should never be run flat. The maximum remended discharge is 75% of the total. This means that the battery should have a minimum of 25% of charge remaining when it is put on charge.Lead acid batteries once filled with electrolyte, should always be regularly charged even if they are not in use. When left idle a filled battery will self discharge because of its own internal resistance. Storage also affects the rate of discharge. A battery should never be stored d