{"id":367,"date":"2017-05-16T15:06:37","date_gmt":"2017-05-16T13:06:37","guid":{"rendered":"https:\/\/www.keenlab.de\/?p=367"},"modified":"2017-05-16T15:06:37","modified_gmt":"2017-05-16T13:06:37","slug":"battery-bms-development","status":"publish","type":"post","link":"https:\/\/www.keenlab.de\/index.php\/2017\/05\/16\/battery-bms-development\/","title":{"rendered":"Battery BMS development"},"content":{"rendered":"<p>The battery pack is not short-circuit proof on its own (well, practically they are, because the power connector provides well isolation against shorts &#8211; however the safety standard does not consider this possibility), so I decided to develop a BMS for it. (And consequently have to redesign the main controller board <em>again<\/em>.)<\/p>\n<p>The key requirements are chosen to be able to pass all today&#8217;s (and hopefully also tomorrow&#8217;s) safety tests:<\/p>\n<ul>\n<li>charge and discharge overcurrent protection<\/li>\n<li>short-circuit protection<\/li>\n<li>individual cell overvoltage and undervoltage protection<\/li>\n<li>separate under- and overtemperature protection for charge and discharge<\/li>\n<li>cell balancers<\/li>\n<li>fits to the battery&#8217;s front face<\/li>\n<li>cost effective<\/li>\n<li>programmable<\/li>\n<li>remote monitoring and control via I2C<\/li>\n<li>15A continuous load current<\/li>\n<\/ul>\n<p>Intersil has released a new family of full blown BMS IC&#8217;s that meets all my requirements: ISL94202 \/ ISL94203. The earlier is intended for packs with a common charging and discharging port, the latter is optimized for packs with separate ports. The actual difference is subtile, but chosing the wrong one (as I did of course) causes problems in certain conditions. The Intersil support staff is responsive and competent, which helped to sort this out quickly.<\/p>\n<p>Here are some pictures of the first prototypes:<\/p>\n<p>Finished board<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-374\" src=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms1.jpg\" alt=\"\" width=\"500\" height=\"423\" srcset=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms1.jpg 500w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms1-300x254.jpg 300w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms1-173x146.jpg 173w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms1-50x42.jpg 50w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms1-89x75.jpg 89w\" sizes=\"auto, (max-width:767px) 480px, 500px\" \/><\/p>\n<p>Temperature sensor, thickened with heat shrink tubings<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-378\" src=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms5.jpg\" alt=\"\" width=\"500\" height=\"469\" srcset=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms5.jpg 500w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms5-300x281.jpg 300w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms5-156x146.jpg 156w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms5-50x47.jpg 50w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms5-80x75.jpg 80w\" sizes=\"auto, (max-width:767px) 480px, 500px\" \/><\/p>\n<p>Connecting it to the pack<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-375 size-full\" src=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms2.jpg\" alt=\"\" width=\"500\" height=\"462\" srcset=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms2.jpg 500w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms2-300x277.jpg 300w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms2-158x146.jpg 158w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms2-50x46.jpg 50w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms2-81x75.jpg 81w\" sizes=\"auto, (max-width:767px) 480px, 500px\" \/><\/p>\n<p>Finished connecting<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-376 size-full\" src=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms3.jpg\" alt=\"\" width=\"500\" height=\"438\" srcset=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms3.jpg 500w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms3-300x263.jpg 300w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms3-167x146.jpg 167w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms3-50x44.jpg 50w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms3-86x75.jpg 86w\" sizes=\"auto, (max-width:767px) 480px, 500px\" \/><\/p>\n<p>Packs ready for testing!<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-377 size-full\" src=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms4.jpg\" alt=\"\" width=\"500\" height=\"375\" srcset=\"https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms4.jpg 500w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms4-300x225.jpg 300w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms4-195x146.jpg 195w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms4-50x38.jpg 50w, https:\/\/www.keenlab.de\/wp-content\/uploads\/2017\/05\/1704-bms4-100x75.jpg 100w\" sizes=\"auto, (max-width:767px) 480px, 500px\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The battery pack is not short-circuit proof on its own (well, practically they are, because the power connector provides well isolation against shorts &#8211; however the<span class=\"excerpt-hellip\"> [\u2026]<\/span><\/p>\n","protected":false},"author":5,"featured_media":374,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-367","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-allgemein"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/posts\/367","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/comments?post=367"}],"version-history":[{"count":1,"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/posts\/367\/revisions"}],"predecessor-version":[{"id":379,"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/posts\/367\/revisions\/379"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/media\/374"}],"wp:attachment":[{"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/media?parent=367"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/categories?post=367"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.keenlab.de\/index.php\/wp-json\/wp\/v2\/tags?post=367"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}