Batteries in Diabetes Technology Devices and Recycling: Need for Eco-Design

Abstract

Batteries are an essential component of many medical products used for diabetes therapy. The increased use of such products comes along with millions of batteries that are disposed of every year. The design of these products should enable the recycling of batteries as they contain a significant number of valuable resources. Regulations in the United States and the European Union concerning batteries used in medical products are changing toward requiring and supporting establishing recycling procedures. Currently, respective programs are active only in some countries. A greener diabetes therapy would include more attention to reducing usage and disposing of batteries.

Introduction

In many medical products used by people with diabetes (PwD) for their daily therapy, batteries have an important role. They supply the electrical power needed for sensing glucose, pumping insulin, storing data, communicating with other devices, running small computers for calculating data, displaying data, buzzing alarms, and so on. Not many manuscripts dealing with the usage of batteries (an essential part of diabetes devices) have been published up to now. ¹

Currently, such devices are used by hundreds of millions per year; however, the rapid increase in diabetes technology most probably will continue in the years to come. The advantages of such products in terms of improving glycemic control, safety, and quality of life are overwhelming. The disadvantage of this increase in usage is the increment in the amount of waste generation year by year.^2-4

In this article, we discuss the need for ecologically sound disposal and recycling of components of batteries used for diabetes devices from three perspectives:

1. optimizing the design of battery components,

2. complying with disposal regulations, and

3. promoting eco-design, disposal programs, and recycling programs.

Recognizing that batteries are essential for the proper functioning of many diabetes devices does not mean that the increase in critical waste resulting from rising use must be accepted as a given. Looking ahead, there is a need for recycling options for diabetes devices like systems for continuous glucose monitoring (CGM; glucose sensors and inserters) and insulin pens—especially smart pens.

From the perspective of battery components, we discuss:

1. the magnitude of the battery recycling issue,

2. whether a given device contains a battery,

3. the types of batteries used in diabetes devices, and

4. the issue of remaining charge in a disposed battery.

From the perspective of regulations, we discuss what is needed for compliance. From the perspective of recycling, we discuss:

1. eco-design,

2. battery accessibility of devices,

3. collection programs, and

4. recycling programs.

How Many Batteries Are Used for Diabetes Devices Per Year?

It is difficult to estimate how many diabetes devices are used in total per year worldwide; however, when focusing on CGM systems, it is assumed that there are currently at least 9 million users. ⁵ Assuming that a given user needs 26 sensors per person per year (with 14 days of usage) or 36 sensors per person per year (with 10 days of usage), a mean value of 30 sensors and 10 million users would amount to approximately 300 million batteries for CGM systems worldwide per year. In view, of the total amount of such batteries manufactured per year, which are used in numerous other devices as well, this is not overwhelming. Nevertheless, it is a significant number, and we should try to establish a recycling process to reuse the batteries. However, depending on the type of battery, the benefits of doing so might differ. It is worth mentioning that the batteries used for glucose sensors are so-called “mini-batteries,” whereas those used in insulin pumps are significantly larger. A given battery might be small; however, the number of batteries used in general for diabetes therapy adds up, and their usage will increase in the future! The same holds true for plastic parts/printed boards/electronic parts in such devices as well. One should consider recycling these parts as well; when attention is taken to one component (like batteries), it should be easier to handle the other parts as adequately.

Does This Device Contain a Battery? And if so, Then Which Type?

Batteries are most often invisible. Some devices may contain more than one battery; for example, in insulin pumps, a small battery might back up data when the main battery (that drives the motor of the pump) is running low or being changed.

The first consideration when talking about recycling batteries is a simple one: Does this device contain a battery at all? This might sound trivial; however, the assumption is that in many cases, the user (and the healthcare professionals (HCPs)) has no clue if a given device contains a battery and—in the second step—which kind of battery is implemented in. This is of relevance as batteries differ concerning their recyclability. ¹ Therefore, the way a given device should be handled when it comes to discharging/recycling might differ. One suggestion is that diabetes devices should have a visible mark/icon that helps the user to identify devices with batteries in them, probably with a piece of information about the type of battery added and advice for proper disposal.

Different Types of Batteries and Each Type Has Its Pros and Cons

The task(s) a battery has to fulfill in a given device, the amount of charge it must hold, and the characteristics of its performance drive the selection of the type of battery used. ¹ In addition, considerations like costs and availability will drive such decision processes; however, most probably not the environmental aspect associated with a given type of battery, at least not until now.

There are several different manufacturers for batteries used in diabetes devices. Many are located in China or South Korea (eg, CoinCell from China, ⁶ representatives of which attend large diabetes conferences; however, the word sustainability (or the topic in general) is not mentioned on their respective homepage). However, Renata, a battery manufacturer from Switzerland, ⁷ provides at least some thoughts about the topic and what they are doing to reduce environmental issues during the manufacturing of the batteries and with respect to recycling, with a focus on batteries that contain silver oxide. ⁸

Charge Remaining in the Batteries When They Are Discharged

To our understanding, when the diabetes devices are discharged, most often the batteries built into the devices still have electrical charge remaining. This “surplus” apparently is important because of storage of the medical product, which can be several months or even longer, and declining battery performance at low ambient temperatures. In practice, the selection of batteries during the design process is driven by the usual factors, that is, the demand is calculated, and then, to be in the safe side, a higher capacity is chosen to ensure a safety buffer. They want to avoid running low on electrical energy to prevent the given device from stopping its function and/or having some kind of malfunction. However, one wonders to which degree the batteries are “over-dimensioned” to be on the safe side. This approach by the engineers needs at least a critical discussion.

Regulations in the United States

In the United States, disposal of lithium batteries (how and where they are disposed of) is regulated under the Resource Conservation and Recovery Act (RCRA) by the Environmental Protection Agency (EPA). The EPA classifies most spent lithium-ion batteries as hazardous waste—not general waste—and allows them to be managed as “universal waste” under streamlined rules. ⁹ The US Department of Transportation (DOT) Hazardous Material Regulations (HMR) (49 CFR Parts 171–180) regulates the transportation of hazardous materials, including lithium batteries, whether they are being shipped for disposal, recycling, or any other purpose. ¹⁰

Regulations in the European Union

In the European Union (EU), a switch to better recyclability of diabetes devices might be driven by the European Commission. The manufacturers of medical products are also subject to “extended producer responsibility” (EPR), which become a legal rule from 2030. This includes responsibility for recycling their products. In other words, they must design their products for recycling. ¹¹

In the EU, the manufacturer of batteries also must fulfill the requirements of a battery regulation. This EU Battery Regulation has been in force since February 18, 2024. As a component of the European Green Deal, it is intended to regulate and simplify the assessment and standardization and thus the legal framework of battery types and the associated obligations in the EU countries. This regulation is also intended to ensure proper disposal and recycling of batteries. ¹² In addition to registration and labeling obligations, this regulation also includes the take-back of batteries and the promotion of environmentally friendly recycling (or, if applicable, participation in an approved battery return system): “The Battery Directive of 2006 and the 2023 Batteries Regulation reiterate the principle of producer responsibility for collecting and recycling waste batteries. In particular, Article 59 of the new Batteries Regulation introduces several changes in terms of content and obligations related to the collection and recycling of waste batteries.”

In Germany, there are legal rules that oblige manufacturers of electrical or electronic equipment to take responsibility for the entire life cycle of their products, which means under EPR that a manufacturer is legally required to ensure the safe disposal of its equipment, including the collection, treatment, and recycling of old/broken products. The medical device manufacturers are responsible under the WEEE Directive (Directive on Waste Electrical and Electronic Equipment 2012/19/EU, revised version 2024/884/EU) to take care of recycling. Manufacturers must register and receive a WEEE number. For battery recycling, over 300 take-back systems exist in the EU. For example, in Switzerland, “Inobat” acts as a battery-collection point; each municipality has its recycling/collection point where batteries can be disposed of. ¹³ These are also collection points for electronic devices (including medical devices). A medical device manufacturer must register with the relevant national authorities in each country in which they distribute or sell devices, irrespective of health regulations, following the requirements of the aforementioned directives/regulations/laws.

Eco-Design

In comparison to other electronic devices, the glucose sensors of CGM systems are relatively small. Users prefer small and light sensors that are waterproof. This requires the compact design of the sensors, which must accommodate the battery. They are designed for a maximum use of ~2 weeks before disposal, only allowing batteries with a high energy density, that is, small weight and volume. For user convenience, a disposable battery is thus the best solution and favored over rechargeable ones. Of note, larger devices such as insulin pumps can be used with rechargeable batteries in certain cases. In terms of eco-design, such rechargeable batteries would be preferred, as they would only need to be disposed of after many hundreds to thousands of charge cycles. It is worth mentioning that there are huge differences between the available devices. For example, the battery life of smart pens varies between a few months and several years.

In glucose sensors, the disposable battery is soldered onto the printed circuit board. For recycling, the sensors have to be shredded and, using sieves, magnets, and other mechanical separation processes, be broken down into its basic components: plastics, metals, and “black mass.” The electrolyte from the batteries is normally thermally vaporized/burned and has to be washed out of the exhaust air. The “black mass” then contains the electrode materials in a largely discharged state, which can be separated again metallurgically.

In order to remove the battery from the glucose sensor for recycling without such a process, an option would be to have a design that allows one to open the device and remove the battery and/or the printed board, in case these form a single unit. The current design of many diabetes devices does not allow accessing such parts without destroying their plastic housing. One reason for completely embedding a battery in a plastic shell is to improve/guarantee water resistance, as the user might like to take a shower, while the glucose sensor is attached to the upper arm or the abdomen.

In addition, many manufacturing processes used for the mass production of products are optimized without much consideration for life cycle or eventual recycling. However, if we want to have medical products that enable the recycling of the different parts of a given product, then the engineers and designers that design a new product should consider the types of plastic and batteries that the product will use (Figure 1).

Figure 1.

Schematic representation of a possible recycling process for insulin pens.

Another option to reduce waste is the lifespan of a given device; for example, just a few days longer usage time per glucose sensor would result in a significantly lower overall “battery load.” Usage of alternative battery/energy technologies with rechargeable transmitters is also an option to reduce waste.

We must acknowledge that a manufacturer is more focused on component costs and manufacturing issues than optimal recycling options. Nevertheless, this is the change in mindset that we believe is mandatory! Manufacturing is a topic most diabetologists have limited insight into. ¹⁴ In case a given manufacturer is changing the design (and manufacturing) of his products in a way, that supports recycling, then the manufacturer should be allowed to market this feature accordingly and receive some sort of financial incentive.

Another hurdle for designing new products and/or revising the production process of existing products is regulatory hurdles. Thus, switching to an Eco-Design requires more considerations than one might think at first glance.

Recycling of Batteries—Accessibility

Currently, PwD are left to the question in which garbage box a used device shall go, general waste or recycling? In practice, today it is most often discharged in general waste. ⁴ The PwD must be aware of the topic of recycling in general and willing/able to handle the given medical product differentially from all the other waste. They must be aware of recycling options and be able to assess them.

When we consider reducing the amount of plastic waste generated at the same time and how we might be able to recycle the plastic, for example, with insulin pens, the same should be possible in principle with batteries (and other electronic components in many devices). However, one requirement for recycling is that the batteries are accessible. This might sound straightforward, and with many of the larger batteries that can be used, for example, in insulin pumps, the batteries can be removed relatively easily. Nevertheless, most of the batteries powering glucose sensors are embedded in a way that these devices must be destroyed to get access to them. ¹⁵ In other words, the parts of which a glucose sensor is built are combined in a way to optimize size, weight, water resistance, and so on, but not with ease of recycling in mind. The risk of injury when breaking open the devices to access the batteries is not acceptable, and a pragmatic approach must be taken.

Recycling of Batteries—How to Collect the Devices and Prepare Them?

To be able to recycle the batteries, they have to be removed from the devices (glucose sensors, insulin pods). This is also needed in order to be able to recycle the plastic material, of which most diabetes devices consist of mainly. In case this is not possible and the typical recycling route (see above) has to be used, further processing of the “black mass” is somewhat difficult when this is not sorted by the type of “metal” in it (silver oxide, lithium, etc.). ¹⁶ To run such a process requires that a sufficient quantity is available for the recycling plant, otherwise, the recycler will not accept the material and it will end up in landfills. Large metallurgical plants for battery waste are currently mainly located in Asia, with only pilot lines being set up in Europe. ¹⁷ Recycling silver oxide batteries is a worthwhile endeavor, as pure silver remains in the cell after discharge. Other battery technologies are far less lucrative, and some are even a loss-making venture.

Another issue with medical devices and in vitro diagnostic devices is that they might become infectious during usage. Fortunately, however, batteries used in medical devices that have been in contact with patients are generally not considered infectious waste themselves. The main risk of infection comes from bodily fluids or biological materials that may contaminate the device or its components during use, rather than from the battery itself. ¹⁸ Safe medical device battery disposal practices are presented in Table 1. Regarding the safe recycling of batteries, crushing a lithium-ion battery (but not a silver-zinc battery) can cause a fire, smoke, and a thermal runaway. These batteries should not be crushed. Also mixing of battery chemistries should be avoided because this can lead to fires.

Table 1.

Safe Medical Device Battery Disposal Practices.^9,19

Alkaline batteries can be disposed of in the trash or recycled according to local and national guidelines.

Used lithium-ion batteries must be sent to (1) certified electronics recyclers, (2) participating retailers, or (3) recyclers’ electronics take-back services and not disposed of in trash bins or general.

Safety measures when handling batteries must minimize the risk of short circuits and thus thermal runway, smoke, and fire.

Battery terminals should not come into contact with any metallic substances during cleaning, such as jewelry. Gloves must be worn while disinfecting, sorting, and disposing of the batteries.

Recycling Programs

While some experience exists when it comes to the recycling of insulin pumps, not much has been published until now about the recycling of batteries with respect to diabetes devices. In France, certain insulin pumps (eg, patch pumps) must be recycled. DASTRI (which translates to “Infectious Medical Waste Activities” in English) is a ten-year-old national French initiative designed to safely collect and recycle medical waste generated by patients who self-administer treatments, particularly those using needles, syringes, and other sharps at home. ²⁰ This program includes medical device battery recycling. Thus, at least some experience exists that can be of help in establishing a recycling process for batteries in countries besides France. In the United States, Call2Recycle and such companies as Redwood Materials and EWASTE+ provide drop-off or mail-in services for lithium-ion batteries from a variety of sources, including healthcare settings.

Conclusions

When the Diabetes Technology Society published the Green Diabetes Declaration in 2022, one statement was with respect to establishing a recycling process for batteries and changing the design/manufacturing process of diabetes devices in a way that supports recycling. ²¹ Building up such a process requires forming a coalition of more than one party involved; it is not only the manufacturer. It is not only them that are responsible for battery disposal and recycling because the regulatory authorities, health policymakers, payers, HCP, and the PwD also have responsibilities for this process. In other words, a coalition is needed to advance this process. If we want to proceed with the idea of making diabetes care greener, then we should pay more attention to batteries and establish a recycling process for them. There is a need and a pathway for the environmentally sound disposal and recycling of battery components used in diabetes devices. As Avari et al ¹ have discussed in detail, batteries are a key component of diabetes devices. Zinc-silver oxide and lithium metal-manganese batteries are preferred due to their reliability and long-term stability. The authors estimate the global number of batteries disposed of in diabetes devices to be around 200 million annually. Apart from the waste of valuable resources, Avari et al also highlight the significance of the whole battery supply chain from acquisition of raw materials to their disposal. As the authors state, the extraction of these raw materials is not only associated with environmental damage and high water consumption but also the use of dangerous chemicals. Disposal of these batteries leads to the destruction of dozens of tons of rare raw materials such as lithium, zinc, silver oxide, and manganese oxide yearly, a process with often involves the release of hazardous gases and the contamination of soil. The authors also point out in their comment that due to the trend toward electrification, a shortage of battery raw materials is to be expected.

Taking all these points into consideration, one must conclude that stakeholders in diabetes care should promote a design of battery components that supports sustainability and comply with applicable disposal regulations. Environmentally sound design, disposal systems, and recycling programs can be combined to create a sustainable solution.