研究：公共充电器远不如之前报道的可靠

旧金山湾区超过四分之一的单元无法运行或设计失败。

2022 现代 Ioniq 5 在 Electrify America 站快速充电

美国东部时间2022 年 6 月 7 日下午2:58

作者：马克凯恩

公共直流快速充电站的可靠性是电气化的关键因素，根据最近的一项研究，目前令人失望。

加州大学伯克利分校的 David Rempel 和 Carleen Cullen 与其他研究人员一起测试了657 个单独的 CCS 连接器（组合充电系统 1/SAE J1772），可在大湾区的181 个开放式公共充电站使用。

事实证明，只有72.5%的单元运行正常（至少进行 2 分钟的测试），而超过四分之一 (27.5%) 的单元无法运行 (22.7%) 或出现设计故障，例如电缆太短 (4.9%)。

“如果 EVSE 为 EV 充电 2 分钟或在评估站时正在为 EV 充电，则 EVSE 被评估为功能性。总体而言，657 个 EVSE 中有 72.5% 是功能性的。电缆太短而无法到达 EV 入口占EVSE的4.9%。22.7% 的 EVSE 无法运行的原因是无响应或屏幕不可用、支付系统故障、充电启动故障、网络故障或连接器损坏。

这是一个不可接受的低水平，考虑到直流快速充电器是运输的关键基础设施，以及在当前阶段，充电站之间的距离通常不允许跳过充电器，我们需要让公众相信 BEV是一种实用且可靠的解决方案。

结果远低于之前报告的结果，根据研究，这并不是坏运气，因为在第一次评估后大约 8 天对 10% 的充电器进行的随机评估显示，功能结果没有整体变化。

72.5% 的水平远低于公共资助机构要求的 97% 至 99% 的最低正常运行时间。

为了行业着想，作者建议制定一个新标准来衡量充电基础设施的可靠性，考虑到将花费数十亿美元购买更多的充电器，这是一个非常好的（也是迟来的）想法。

“这种功能水平似乎与运营电动汽车充电站的电动汽车服务提供商 (EVSP) 报告的 95% 到 98% 的正常运行时间相冲突。研究结果表明，需要对可靠性、正常运行时间、停机时间进行共享、精确的定义和计算，并排除时间，适用于开放的公共 DCFC，并通过第三方评估进行验证。”

关于问题的类型，占比最高的似乎是支付系统故障 (7.2%) 和收费启动失败 (6.4%)，其次是屏幕上的错误消息 (3.7%) 和空白或无响应屏幕 ( 3.5%），而只有 1.1% 是由连接错误或 0.9% 由连接器损坏引起的。它表明这些问题通常与通信和软件有关。

另一个有趣的事情是特定充电网络的可靠性。大样本 ChargePoint、Electrify America 和 EVgo 共占所有测试充电器的 639 台或 97.2%。

正如我们在下面看到的，所有这些都远低于可接受的水平——ChargePoint 为 61.4%，EVgo 为 72.7%，Electrify America 为 73.9%。令人惊讶的是，在 Electrify America 的案例中，电缆长度是 7.1% 的摊位问题。

作为参考， 特斯拉超级充电网络（在美国不是 CCS）---根据特斯拉的说法是 99.96% 可靠，使用了一种非常不同的方法。

如果作者对特斯拉和特斯拉增压器进行相同的研究以看到结果，那就太好了。

全文中的更多详细信息：开放式公共电动汽车直流快速充电器的可靠性 - 加州大学伯克利分校

来源：汽车新闻

马克凯恩

作者：马克凯恩

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Study: Public Chargers Far Less Reliable Than Previously Reported

More than a quarter of the units in the San Francisco Bay Area were not functioning or had a design failure.

2022 Hyundai Ioniq 5 fast charging at a Electrify America station

Jun 07, 2022 at 2:58pm ET

By: Mark Kane

The reliability of the public DC fast-charging stations is a crucial element of electrification and, according to a recent study, it's disappointing right now.

University of California Berkeley's David Rempel and Carleen Cullen, together with other researchers, tested a total of 657 individual CCS connectors (Combined Charging System 1/SAE J1772), available at 181 open, public charging stations in the Greater Bay Area.

As it turns out, only 72.5% of the units were functioning (working for at least 2 minutes of testing), while more than a quarter (27.5%) were not functioning (22.7%) or had a design failure in the form of a cable that was too short (4.9%).

"An EVSE was evaluated as functional if it charged an EV for 2 minutes or was charging an EV at the time the station was evaluated. Overall, 72.5% of the 657 EVSEs were functional. The cable was too short to reach the EV inlet for 4.9% of the EVSEs. Causes of 22.7% of EVSEs that were non-functioning were unresponsive or unavailable screens, payment system failures, charge initiation failures, network failures, or broken connectors."

It's an unacceptably low level, considering the fact that DC fast chargers are critical infrastructure for transport, as well as at the current stage, the distance between charging stations often does not allow to skip a charger and we need to convince the general public that BEVs are a practical and reliable solution.

The result is far lower than previously reported and, according to the study, it's not bad luck, as a random evaluation of 10% of the chargers, approximately 8 days after the first evaluation, demonstrated no overall change in functionality results.

The paper notes that the level of 72.5% is far below the 97 to 99% minimum uptime required by public funding agencies.

For the sake of the industry, the authors propose to create a new standard to measure the reliability of charging infrastructure, which is a pretty good (and late) idea, considering that billions will be spent on more chargers.

"This level of functionality appears to conflict with the 95 to 98% uptime reported by the EV service providers (EVSPs) who operate the EV charging stations. The findings suggest a need for shared, precise definitions of and calculations for reliability, uptime, downtime, and excluded time, as applied to open public DCFCs, with verification by third-party evaluation."

In regards to the type of issues, the highest share seems to be Payment system failure (7.2%) and Charge initiation failure (6.4%), followed by an Error message on screen (3.7%) and a Blank or non-responsive screen (3.5%), while only 1.1% was caused by Connection error or 0.9% by Connector broken. It suggests that the issues are often related to communication and software.

Another interesting thing is the reliability of particular charging networks. There were three large samples ChargePoint, Electrify America and EVgo, which together accounted for 639 or 97.2% of all tested chargers.

As we can see below, there are all far below acceptable levels - ChargePoint at 61.4%, EVgo at 72.7% and Electrify America at 73.9%. A surprising thing is that in the case of Electrify America, the cable length is an issue at 7.1% of the stalls.

For reference, the Tesla Supercharging network (which is not CCS in the US) is - according to Tesla - 99.96% reliable, using a very different methodology.

It would be great if the authors would conduct the same study on Teslas and Tesla Superchargers to see the result.

More details in full paper: Reliability of Open Public Electric Vehicle Direct Current Fast Chargers - University of California Berkeley

Source: Automotive News

Mark Kane

By: Mark Kane

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