Battery pack maintenance

Abstract

Aspects of the invention relate to a method (1000) for releasing a first component (100) of a battery pack (1) from a battery pack (1), a battery pack (1) and a vehicle (50). The first component (100) is fixed to the second component (100) of the battery pack (1) by adhesive bonding (120). The method (1000) includes applying a load to the first component (100) in a direction away from the second component (200), and flowing a thermal conditioning fluid through the cavity (300) of the battery pack (1) to create a temperature gradient between the first component (100) and the second component (200) such that the adhesive bond (120) is weakened. The first component (100) is separated from the second component (100) by means of the applied load.

Description

Technical Field

[0001] This disclosure relates to battery pack repair. Aspects of the invention relate to a method for releasing a first component of a battery pack from the battery pack, the battery pack itself, and a vehicle. Background Technology

[0002] Battery packs are used in electrified vehicles such as battery electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and fuel cell electric vehicles. Such battery packs typically contain a large number of individual battery cells (“cells”), which can be in the form of prismatic, pouch, or cylindrical cells. Cells may include rechargeable cells and / or capacitors. Cells are typically arranged in cell sub-assemblies (“modules” or “stacks”) within the battery pack. Components of the battery pack are known to be secured by various fasteners such as clips, rivets, screws, nuts, and bolts, as well as by various types of adhesives formed from structural and semi-structural adhesives. In so-called “cell-to-pack” arrangements with few or no intermediate module structures, applying structural and semi-structural adhesives to the cells provides distributed reinforcement benefits to the battery pack that cannot be achieved by using concealed fasteners such as rivets and screws alone. Such battery packs are expected to be repairable, enabling the failed battery pack to be restored to a functional state after one or more cells fail and need replacement. However, when the battery pack needs maintenance, the adhesive is not as easy to remove as the concealed fasteners.

[0003] The desired approach is to repair battery packs by removing only the faulty components, cells, or cell sub-assemblies, without damaging the rest of the pack during the repair process. Current methods for repairing battery packs using adhesives rely on separating the faulty component by mechanically loosening it from the rest of the pack. These methods involve peeling and chiseling away the adhesive from the cell, but this can be difficult when the adhesive bonding is not readily accessible. The desired approach is to provide a battery pack and repair method where some adhered cells can be separated from the pack without damaging the rest of the pack.

[0004] The purpose of this invention is to address one or more of the disadvantages associated with the prior art. Summary of the Invention

[0005] The various aspects and embodiments of the present invention provide methods, battery packs, and vehicles as claimed in the appended claims.

[0006] According to one aspect of the present invention, a method is provided for releasing a first component of a battery pack from the battery pack, the first component being bonded to a second component of the battery pack by an adhesive, the method comprising:

[0007] Apply a load to the first component in a direction away from the second component;

[0008] A thermally regulating fluid is circulated through the cavity of the battery pack to create a temperature gradient between the first and second components, thereby weakening the adhesive bond; and

[0009] The first component is separated from the second component by means of the applied load.

[0010] This method is useful in battery pack repairs where one or more components or sub-assemblies need to be removed. It provides a way to induce adhesive failure due to differential thermal expansion between at least the first and second components, as well as the adhesive itself. Advantageously, this weakens or loosens the adhesive bond, making the component removable from the battery pack. This method is useful for weakening adhesive bonds that are difficult to access by mechanical means. Furthermore, providing a temperature gradient at the adhesive bond eliminates the need to apply high temperatures to other components of the battery pack that have not been removed. Applying a load before heating causes separation to occur once the adhesive bond is weakened. Heating before applying the load, or heating and applying the load simultaneously, is also useful in loosening joints.

[0011] Optionally, the temperature of the thermally regulating fluid is higher than the temperature of the battery pack, causing the temperature of the adhesive bonds to rise as the fluid flows through the cavity. This provides a way to induce both cohesive and adhesive failure of the adhesive bonds. Advantageously, adhesive bonds that are difficult to remove can be further weakened through both cohesive and adhesive failure.

[0012] Optionally, the flow of the thermal conditioning fluid is controlled to maintain the temperature of the battery pack within predetermined limits. Temperature control provides protection for the remaining cells in the pack. Advantageously, the remainder of the battery pack is reusable.

[0013] Optionally, applying a load to the first component includes applying a load to a load attachment point extending from a first end of the first component to peel the first component from the second component. This provides a way to transfer a single load to one or more cells in a cell sub-assembly. Advantageously, multiple cells can be removed in a single operation. The method also initiates a peeling action, which is a controlled manner of removing components from the battery pack. The method provides a separation force at the edges of the adhesive bond. The peeling load is lower than the load that would cause the entire first component to suddenly detach (dissociate).

[0014] Optionally, the adhesive bond is substantially located within the adhesive plane between the first and second components, and a load is applied to the load attachment point in a direction approximately perpendicular to the adhesive plane. Advantageously, applying the load perpendicularly provides an efficient way to separate the components with a lower load than when the load is applied obliquely or in a plane.

[0015] Alternatively, an external clamp applied to the surface of the battery pack can be used to form the cavity. The cavity is provided only during maintenance and is not part of the battery's structure during use. This simplifies battery design. A cavity entirely outside the battery pack can also be provided.

[0016] Alternatively, the cavity is formed as a channel within the second component. This provides a simple way of providing the cavity because the channel can also be formed as part of a structural portion, such as a box-shaped portion or an extrusion; that is, the channel can be provided for structural rigidity purposes and also has the additional use of being a cavity in this invention. Advantageously, a single component including the channel can be used for more than one purpose. Furthermore, if the cavity in the second component with a second purpose is used to receive a thermoregulating fluid, it is not necessary to manufacture a custom cavity.

[0017] Alternatively, the battery pack includes a third component arranged in thermal contact with the second component, and a cavity is formed within the third component as a channel. This provides a simple way to use a channel as a cavity, as the channel can be located within a structural portion of the third component. The structural portion can be part of a box-shaped portion or an extrusion that is in thermal contact with the second component. Advantageously, the third component including the channel can be used for more than one purpose. Furthermore, if a cavity is used in the third component, it is not necessary to manufacture a custom cavity for receiving thermally conditioned fluid.

[0018] Optionally, the battery pack includes a substrate arranged in thermal contact with the second component, and a cavity is formed as a channel within the substrate. This provides a simple way to use a channel as a cavity, since the channel can be within a structural portion of the substrate, such as a box-shaped portion or part of an extrusion that is in thermal contact with the second component. Advantageously, a substrate including a channel can be used for more than one purpose. Furthermore, if a cavity in the substrate is used, it is not necessary to manufacture a custom cavity for receiving thermally regulated fluid.

[0019] Optionally, the heat-regulating fluid flows into the cavity via one or more inlet ports and out of the cavity via one or more outlet ports. This provides a manner for the fluid to flow through the cavity. Advantageously, the flow rate can be controlled by the size of the ports. Optionally, the one or more inlet ports and / or the one or more outlet ports can be formed by drilling holes into the cavity.

[0020] Alternatively, the heat conditioning fluid is a hot gas, such as hot air.

[0021] According to another aspect of the present invention, a battery pack is provided for housing battery cells within a sealed internal volume of the battery pack, the battery pack comprising:

[0022] A first component and a second component, wherein the first component is bonded and fixed to the second component by an adhesive; and

[0023] A battery panel arranged in thermal contact with a second component, wherein the battery panel includes a cavity outside the sealed internal volume of the battery pack, such that a thermally regulating fluid can flow through the cavity of the battery panel to create a temperature gradient between the first and second components, for weakening adhesive bonding during maintenance of the battery pack.

[0024] In this way, the inlet and / or outlet ports can be discharge ports within a wet zone. Wet zones in a vehicle are known to be dirty areas and are therefore advantageously sealed relative to the vehicle's interior areas, and particularly, relative to those areas containing sensitive components such as the internal volume of the battery pack. Cavities in the substrate can be wet zones. Advantageously, drilling ports into cavities outside the sealed internal volume of the battery (e.g., wet zone cavities) will prevent chips from entering the sensitive internal portions of the battery pack.

[0025] Optionally, the first component includes a cell assembly, the cell assembly comprising:

[0026] At least one battery cell;

[0027] A flexible cell carrier having a first side fixed to each of the at least one battery cell, and a second side fixed to a second component by an adhesive bonding; and

[0028] The load attachment point extending from the first end of the cell carrier

[0029] This causes the flexible cell carrier to peel off from the second component starting from the first end when a load is applied to the load attachment point.

[0030] The cell carrier provides flexibility for the separation of cell sub-assemblies. Advantageously, cell sub-assemblies can be easily removed from the battery pack.

[0031] Optionally, the battery pack further includes a discharge port for venting the cavity during use, and the discharge port is configured to allow thermal conditioning fluid to flow through it during battery pack maintenance. The inlet and / or outlet ports can be discharge ports in wet areas. Wet areas of a vehicle are known to be dirty areas and are therefore advantageously sealed relative to the vehicle's interior areas, and in particular, relative to those areas containing sensitive components such as the internal volume of the battery pack. Advantageously, drilling or bulging ports into cavities sealed to the internal volume of the battery pack will prevent chips from entering the sensitive internal parts of the battery pack.

[0032] According to another aspect of the invention, a vehicle including a battery pack is provided.

[0033] Within the scope of this application, it is expressly intended that various aspects, embodiments, examples, and alternatives set forth in the preceding paragraphs, claims, and / or the following description and drawings, and in particular their various features, may be adopted independently or in any combination. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination, unless such features are incompatible. The applicant reserves the right to amend any originally filed claim or accordingly file any new claim, including the right to modify any originally filed claim to any feature subordinate to and / or incorporated into any other claim, even though it was not initially claimed in this manner. Attached Figure Description

[0034] One or more embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:

[0035] Figure 1 This is a schematic diagram of the components in the battery pack;

[0036] Figure 2 An example of the steps of a method for releasing a first component of a battery pack from the battery pack is shown;

[0037] Figure 3 An example battery pack is shown;

[0038] Figure 4 The cover and battery cell are shown below. Figure 3 The battery pack;

[0039] Figure 5 A schematic diagram of a vertical cross-section passing through a portion of the battery pack is shown;

[0040] Figure 6 A vertical cross-section passing through a portion of the battery pack is shown;

[0041] Figure 7 It shows Figure 6 Detailed views of the components;

[0042] Figure 8 The cell carrier and load attachment points are shown; and

[0043] Figure 9 An example of a vehicle is shown. Detailed Implementation

[0044] This document describes, with reference to the accompanying drawings, a battery pack 1 according to an embodiment of the present invention and a method for releasing a first component from the battery pack.

[0045] Figure 1 A battery pack 1 is shown, comprising a first component 100 and a second component 200, which are adhered together by an adhesive bond 120. A cavity 300 exists within the second component 200. Alternatively, this cavity may be associated with other components of the battery pack 1. The first component 100 and / or the second component 200 may each include a cell module, an individual cell, a structural component, a cover, a plate, a cooling component, a busbar, a sensor, a circuit board, a valve, a pump, or any other component or sub-assembly of the battery pack 1. In this example, the first component 100 includes a cell stack and the second component 200 includes a structural component. The first component 100 may include a sub-assembly of faulty battery cells that need to be replaced during maintenance of the battery pack 1.

[0046] Repairing faulty battery pack 1 requires detaching the adhesive bonded to 120, possibly by mechanical loosening or some other method. Figure 1 In this case, because the adhesive bond 120 is located below the first component 100, the adhesive bond 120 is not easily accessible to be loosened mechanically.

[0047] One method for debonding is to use a thermal adhesive. However, such a thermal adhesive will debond at temperatures within the operating range of battery pack 1 (i.e., below approximately 30°C to 45°C, depending on the cell chemistry used for charge storage). Therefore, such a thermal adhesive would be unsuitable because it would debond during normal vehicle use.

[0048] Another method of debonding is to use an adhesive that debonds at temperatures above the operating range of battery pack 1. However, heating the battery cells to high temperatures can cause chemical aging of the cells and thus reduce their energy capacity. Providing heat to the internal volume of battery pack 1 will heat many components other than the part being repaired, including the battery cells within the internal volume. Heating the internal volume can therefore cause thermal damage to battery cells that were not removed as part of the repair operation. The following method of the present invention was developed in this context.

[0049] Figure 2 An efficient method 1000 for releasing a first component 100 from a battery pack 1 is shown. Method 1000 is useful when the first component 100 is secured to one or more second components 200 of the battery pack by adhesive bonding 120 and when it is necessary to separate it from one or more second components 200.

[0050] In the first step 1100, a load L is applied to the first component 100 to be removed from the battery pack 1, and the load L is applied in a direction away from the second component 200.

[0051] In step 1200, a thermally conditioning fluid is flowed through cavity 300 of battery pack 1 to create a temperature gradient between the first component 100 and the second component 200, thereby weakening the adhesive bond 120. The thermally conditioning fluid is a fluid whose temperature is controlled to be different from that of the first component 100 and the second component 200. For example, battery pack 1 may be previously stabilized at room temperature so that the temperature of the first component 100 and the second component 200 are the same. The thermally conditioning fluid is either hotter or colder than the temperature of the first component 100 and the second component 200.

[0052] When a hot or cold fluid flows through the cavity, a temperature difference is generated between the first component 100 and the second component 200 due to the difference in the thermal path between the cavity and the first component 100 and the second component 200. For example, the cavity may have a tighter thermal contact with the first component 100 than with the second component 200. This temperature difference provides a temperature gradient between the first component 100 and the second component 200. It is desirable to rapidly change the temperature of the adhesive bond 120 to achieve a temperature gradient across the adhesive bond 120. Slowly heating the adhesive bond 120 will result in a gentler temperature gradient. A thermally controlled gas is used to rapidly generate a temperature gradient between the first component 100 and the second component 200 without unduly affecting the overall temperature of the rest of the battery pack 1.

[0053] A temperature gradient causes differential thermal expansion of the first component 100, the adhesive bond 120, and the second component 200. The degree of differential thermal expansion depends on the coefficient of thermal expansion of the materials used. Differential expansion generates stress within the adhesive bond, which leads to weakening of the adhesive bond and thus adhesive failure. Adhesive failure is the failure of the interfacial bond between the adhesive and the substrate, that is, the failure of the interfacial bond between the adhesive and one or both of the first component 100 and the second component 200.

[0054] When the heat-regulating fluid is relatively hot compared to the temperature of the first component 100 and the second component 200, the heat-regulating fluid not only provides a temperature gradient that causes adhesive failure between the first component 100 and the second component 200, but also causes heating of the adhesive bond 120. When the adhesive bond is heated, this promotes cohesive failure of the adhesive bond 120. Cohesive failure is a failure within the adhesive itself (also known as adhesive splitting), resulting in some adhesive remaining on each of the first component 100 and the second component 200. For a method to successfully separate the first and second components, the adhesive does not need to melt in a heat-sensitive adhesive manner but only needs to weaken, such that under the applied load L, the adhesive bond 120 fails through adhesive failure, cohesive failure, or a combination of both.

[0055] For this reason, using a hot fluid as a thermal conditioning fluid is preferred in some applications where the adhesive weakens with the application of heat, while using a cold fluid may be preferred in other applications where differential thermal expansion is required and some components in the battery pack are more susceptible to thermal aging effects at higher temperatures.

[0056] In some examples, the flow of the thermal conditioning fluid is controlled to keep the temperature of the battery pack components within predetermined temperature limits. This can be achieved by controlling the fluid's temperature and / or flow rate. In this way, the total thermal energy and power flowing into chamber 300 are controlled, ensuring that the degree of heating or cooling of the components of battery pack 1 is controlled. The possibility of thermal damage to the components of battery pack 1 is then reduced by limiting the upper temperature limit of the components of battery pack 1. The temperature limit can be determined in advance through experiments, computer modeling of the heat flow within battery pack 1, or some other estimation method. The temperature value being sensed is preferably the temperature of a component not removed from battery pack 1 or a replacement for such a component.

[0057] As discussed, the thermally regulating fluid can be a hot fluid supplied by a heating system that heats the fluid and also pumps it into cavity 30. The heating system can be connected to a controller (not shown) that controls the temperature and / or flow rate of the fluid. A temperature sensor is configured to measure the temperature of components of the battery pack, and the output of the temperature sensor is connected to the controller to control the heating system based on the temperature measurement. The temperature sensor can be disposed within adhesive bonding 120, or it can be associated with a cell, cell stack, or cell module. The temperature sensor can be built into the battery pack 1 during manufacturing or can be applied during maintenance operations on the battery pack 1. The temperature sensor can be a thermistor or other such temperature sensors known to those skilled in the art.

[0058] In this example, the hot fluid is hot air, the heating system is a hot air gun, and the temperature is manually controlled by the operator. The example temperature at which the adhesive bond 120 separates is 50°C, and the example adhesive is polyurethane. Other adhesives are also useful, such as glues. For other adhesives, such as glues, different separation temperatures may occur.

[0059] The example hot air gun has a maximum rated power of 1800 watts, three different temperature settings (50°C, 300°C, and 600°C), and three different flow rates (200 l / min, 350 l / min, and 500 l / min). The temperature is managed by the operator through control of the flow rate and / or temperature. Hot air is introduced into chamber 300 through the inlet port and exits the chamber through the outlet port. Other types of hot fluids can be hot gases such as inert gases or nitrogen, which can be used instead of hot air.

[0060] In step 1300, the first component 100 separates from the second component 200 under the applied load L. The load L is applied at any location on the first component 100 and is arranged to pull the first component 100 away from the second component 200, causing the first component 100 to separate from the second component 200. In some examples, applying the load L to the load attachment point 440 at a first end of the first component 100 facilitates the peeling action of the first component 100 away from the second component 200. It will be understood that the application of the load L in step 1100 continues through steps 1200 and 1300 of method 1000 until the first component 100 separates from the second component 200. Step 1100 can be as follows: Figure 2 As shown, this occurs prior to step 1200, in which case, as the adhesive bond 120 weakens, separation of the components occurs. Alternatively, step 1200 may precede step 1100.

[0061] The battery pack 1 has a large mass and thus effectively resists the load L by gravity, but in some embodiments, step 1100 may also include fixing the battery pack 1 to resist the load L applied to the first component 100.

[0062] Figure 3 An example of a battery pack from a battery-electric vehicle is shown, with battery pack 1 having a cover 2 on its upper surface. Figure 4 The image shows the same battery pack 1 with the cover 2 and the cell assembly removed. The cell assembly is a stack or module of battery cells and is an example of the first component 100 in method 1000. Figure 4As shown, the battery pack 1 includes a battery frame 4, which includes structural members 20a and 20b on either side of a central compartment 5 for housing battery cells. Other compartments 6 for housing battery cells are shown on either side of the central compartment 5. In this example, the battery pack 1 includes a total of five compartments 5 and 6. However, it will be understood that in other examples, the battery pack 1 may include any number of compartments 5 and 6 suitable for the desired energy capacity of the battery pack 1.

[0063] Figure 5 A simplified schematic cross-section of compartment 5 in the XZ plane is shown, in which a cell assembly 10 is assembled into compartment 5 and secured to structural members 20a, 20b on its underside by adhesive bonds 12a, 12b. Cell assembly 10 comprises a stack of prismatic rechargeable battery cells. Structural members 20a, 20b are formed by extrusion and include internal cavities 22, 24. Because cell assembly 10 itself blocks access to adhesive bonds 12a, 12b, the adhesive bonds 12a and 12b are difficult to access for mechanical loosening. In this example, adhesive bonds 12a, 12b, in the form of two adhesive strips, are an example of adhesive bond 120 in method 1000. Cell assembly 10 is an example of a first member 100, and structural members 20a, 20b are examples of a second member 200.

[0064] The battery panel 30 surrounds the lower side of the frame 4 on the lower side of the battery pack 1. The battery panel 30 is formed of two metal plates glued together. The lower plate, referred to as the protective plate 34, is adapted to protect the battery from impacts from stones and debris from below the vehicle. The upper plate, referred to as the substrate 32, has a corrugated shape and is used to reinforce the battery panel 30. Cavities 36a and 36b are formed between the substrate 32 and the protective plate 34. The two cavities 36a and 36b are isolated from each other through the area where the substrate 32 and the protective plate 34 are glued together. Another cavity 38 is formed between the upper substrate 32 and the cell assembly 10. This cavity is a sealed internal volume in the battery pack 1 in which the battery cells reside. An adhesive is used in the bonding of the substrate 32 to the structural components 20a and 20b.

[0065] The cavities 36a and 36b in which the heat-regulating fluid flows are Figure 5The cavities of the solar panel 30. Other cavities of the battery pack 1 may be suitable, as long as these cavities are thermally connected to the adhesive bonds to generate a temperature gradient across the adhesive bonds 12a, 12b. In some examples, cavities are formed within the second components 20a, 20b, such as cavities within the extruders 22, 24. Allowing heating fluid to flow within the cavities within the extruders 22, 24 provides a faster heating effect on the adhesive bonds 12a, 12b, but may also heat other components that may not be desirable, depending on whether those components include temperature-sensitive parts. When used in method 1000, the cavities 36a, 36b of the solar panel 30 provide particular benefits, at least for the reasons described below.

[0066] Cavities 36a and 36b of the solar panel 30 are suitable for use in this arrangement because they have good thermal contact with structural components 20a and 20b, and thus good thermal contact with adhesive bonds 12a and 12b. However, the thermal contact between cavities 36a and 36b of the solar panel 30 and the cell sub-assemblies 10 is not good enough, nor is the thermal contact with other unrepaired or unreplaced cell sub-assemblies within the battery pack 1. Therefore, the use of the selected cavities 36a and 36b will not result in thermal aging of those battery cells in the battery pack intended to be protected from damage during maintenance operations.

[0067] Furthermore, the cavities 36a and 36b of the battery panel 30 are suitable for use in this arrangement because the cavities 36a and 36b are sealed relative to the battery cells, preventing thermally regulating fluid from entering the sealed internal volume 38 containing the battery cells, including those cells that were not removed and replaced during maintenance operations. The cavities 36a and 36b of the battery panel 30 are examples of wet zones, having discharge ports (holes) 39a and 39b in the protective plate 34 for draining moisture from the wet zones during use. Wet zones are those cavities that allow moisture to enter during vehicle use. For example, if the vehicle is driven in water, moisture may enter the cavities 36a and 36b of the battery panel through the discharge ports 39a and 39b in the protective plate 34. Wet zones are useful cavities in which thermally regulating fluid flows because they are discontinuous with the sealed internal volume 38 of the battery pack 1. Each of the cavities 36a and 36b is provided with a plurality of discharge ports 39a and 39b, and thus one or more discharge ports 39a and 39b serve as inlet ports for allowing the thermoregulating fluid to flow into the cavities 36a and 36b, and one or more discharge ports 39a and 39b serve as outlet ports for allowing the thermoregulating fluid to flow out of the cavities 36a and 36b. Inlet ports and / or outlet ports can be drilled into any cavity used for allowing the thermoregulating fluid to flow. To provide a suitable flow rate of the thermoregulating fluid, additional inlet ports and / or outlet ports can be easily drilled into the wet zone cavities 36a and 36b without concern for machining chips entering the sealed internal volume 38. The discharge ports can be configured to allow the thermoregulating fluid to flow through them by forming the ports to the required size and / or by providing adapters for connection to the heating system. If more discharge ports 39a and 39b than are required for the entry and / or exit of the thermoregulating fluid are provided in the guard plate 34, the excess discharge ports can be sealed.

[0068] Therefore, the thermal conditioning fluid is flowed through the wet zone cavity of the battery pack 1 to create a temperature gradient between the first component 100 and the second component 100, in order to weaken the adhesive bond 120 during battery pack maintenance.

[0069] In some embodiments of method 1000, cavity 300 is formed by a clamp (not shown) applied to the surface of battery pack 1. The inner surface of cavity 300 is formed by a portion of the surface of battery pack 1. Another inner surface of cavity 300 is formed by a portion of the clamp. In this case, the cavity is formed only during maintenance operations and is not manufactured into battery pack 1 and is not present in battery pack 1 during normal use.

[0070] Figure 6 A vertical cross-section through a portion of the battery pack 1 is shown. In this cross-sectional view, it can be seen that the cell sub-assembly 10 includes both a cell 14 and a cell carrier 16. The cell carrier 16 is attached to the structural component 20a.

[0071] Figure 7 The interface between the cell sub-assembly 10 and the structural component 20a is shown, as well as the adhesive bond 12a between the cell carrier 16 and the structural component 20a. The cell carrier 16 travels along the length of the cell sub-assembly 10.

[0072] exist Figure 8 In the diagram, a cell carrier 16 can be seen carrying a plurality of cell cells 14, wherein the cell cells are fixed to a first side (not shown) of the cell carrier 16. An adhesive bond 12a is applied between the structural member 20a and a second side (not shown) of the cell carrier 16 of the cell sub-assembly 10. Each of the cell cells 14 is adhered to the cell carrier 16. Suitable adhesives for adhering the cell cells 14 to the cell carrier 16 include epoxy resin, cyanoacrylate, or resin. The cell carrier 16 includes an aluminum plate formed in an L-shape, such as... Figure 6 The cross-section is shown. Other materials, such as steel or plastic, are also useful. Other shapes for the cell carrier 16 are also useful, such as flat or box-shaped sections. The cell carrier 16 may partially or completely surround all the cells 14 of the cell sub-assembly 10.

[0073] In this example, the first objective of the cell carrier 16 is to provide a manner for holding the cells stacked together in the sub-assembly 10 during the manufacturing of the battery pack 1. The second objective of the cell carrier 16 is to provide a manner for holding the cells stacked together in the sub-assembly 10 during the release of the cell sub-assembly 10 from the battery pack 1.

[0074] exist Figure 8 In the example, the cell carrier 16 is flexible and the cells 14 are spaced apart along the length of the cell carrier 16. This spacing allows the cells 14 to expand during use and also allows the cell sub-assembly 10 to bend as the cell carrier 16 bends during separation of the cell sub-assembly 10 from the battery pack 1. Figure 8 A lifting ring 42 is shown at a load attachment point 44 at the first end 40 of the cell assembly 10. In some examples, the lifting ring 42 is attached to the cell assembly during removal and maintenance operations. Figure 8 In the example, during the manufacturing of battery pack 1, the lifting ring 42 is already built into the structure of the cell sub-assembly 10. The lifting ring 42 is integral with the cell carrier 16 and extends beyond the end of the cell 14.

[0075] As described above, in step 1300, under the continuous action of the applied load L, the cell sub-assembly 10 separates from the structural components 20a and 20b. The load L is applied by a bridge crane or lifting device, wherein the applied load is measured by an inline force sensor. A non-conductive belt can be used to apply the load. As the first component separates and moves, the crane or lifting device needs to be adjusted to maintain the tension at the desired load L. Alternatively, the load L can be applied by a weight acting on a pulley, in which case the load L remains constant when the first component separates. Figure 8 In the example, the load is applied at the first end of the cell subassembly 10.

[0076] The load attachment point 44 is configured with a slightly upwardly curved portion 46 in the direction of the applied load. When a load L is applied, this slightly curved portion 46 assists in initiating a peeling action of the cell carrier 16 away from the structural component 20a. Peeling is a useful way to separate the first component 100 from the second component 200. Peeling occurs gradually and in a more controlled manner compared to the instantaneous breakage of the entire adhesive bond 12a with the rapid release of the associated first component 100. Peeling typically requires a lower load than the instantaneous breakage of the entire adhesive bond 12a. Figure 8 In the middle, the load L is set at the edge of the adhesive bond 12a.

[0077] The lifting ring 42 can take any form, such as a hook, a retaining nut, or a rivet, as long as it provides a means of attaching a load to the first component. Additional lifting rings can be provided on the cell sub-assembly 10. In some examples, a second lifting ring is present at the second end of the cell sub-assembly 10, allowing the cell sub-assembly 10 to be removed by applying a load to both ends simultaneously, or in two separate operations. In such examples, the cell carrier 16 can be disposed in two or more sections, making the cell sub-assembly 10 removable in two or more sections. The load can be distributed along the length of the cell assembly 10.

[0078] exist Figure 5 , Figure 6 and Figure 7In the example, the adhesive bond 120 lies in the plane between the first component 100 and the second component 200. Preferably, a load L is applied in a direction perpendicular to this plane to efficiently break the adhesive bond 120. Those skilled in the art will understand that a nearly perpendicular direction is also useful, for example, within 10 or 20 degrees of perpendicularity. In some examples, the adhesive bond 120 between the first component 100 and the second component 200 lies substantially or primarily in the principal plane, wherein some of the adhesive bonds in the adhesive bond 120 lie in different planes; in this case, it is still preferable to apply the load L in a direction perpendicular to the principal plane. In some examples, the adhesive bond 120 is applied in two or more planes, and it is useful to apply the load L at a compound angle not exactly perpendicular to either of the two or more planes of the adhesive bond 120. For example, if the adhesive bonds are uniformly located in two perpendicular planes, then applying the load L at an intermediate angle between the two planes, such as 45°, may be useful. The angle selection depends on the relative extent of the two adhesive planes.

[0079] Figure 9 A vehicle 50 is shown, which includes a battery pack 1 as described in the example above.

[0080] It will be understood that various changes and modifications can be made to the invention without departing from the scope of this application.

Claims

1. A method of releasing a first component of a battery pack from the battery pack, the first component being secured to a second component of the battery pack by an adhesive bond, the method comprising: applying a load to the first component in a direction away from the second component; flowing a thermal conditioning fluid through a cavity of the battery pack to create a temperature gradient between the first component and the second component such that the adhesive bond is weakened; and separating the first component from the second component with the aid of the applied load.

2. The method of claim 1, wherein, The thermal conditioning fluid is at a temperature higher than a temperature of the battery pack such that when the fluid flows through the cavity, the temperature of the adhesive bond is increased.

3. The method of any preceding claim, wherein, The flow of the thermal conditioning fluid is controlled to maintain the temperature of the battery pack within predetermined limits.

4. The method of any preceding claim, wherein, Applying a load to the first component comprises: applying the load to a load attachment point extending from a first end of the first component 100 to peel the first component from the second component.

5. The method of claim 4, wherein, The adhesive bond is located substantially within an adhesive plane between the first component and the second component, and wherein the load is applied to the load attachment point in a direction perpendicular to the adhesive plane.

6. The method of any preceding claim, comprising: The cavity is formed using an external clamp applied to a surface of the battery pack.

7. The method of claim 1 to 5, wherein, The cavity is formed within the second component.

8. The method of any one of claims 1 to 5, wherein, The battery pack comprises a substrate arranged in thermal contact with the second component, and the cavity is formed within the substrate.

9. The method of any preceding claim, comprising: The thermal conditioning fluid is flowed into the cavity via one or more inlet ports and out of the cavity via one or more outlet ports.

10. The method of claim 9, comprising: The one or more inlet ports and / or the one or more outlet ports are formed by drilling holes into the cavity.

11. The method of any preceding claim, wherein, The thermal conditioning fluid is hot air.

12. A battery pack for housing battery cells within a sealed internal volume of the battery pack, the battery pack comprising: a first component and a second component, the first component being secured to the second component by an adhesive bond; and a battery plate arranged in thermal contact with the second component, wherein the battery plate comprises a cavity outside of the sealed internal volume of the battery pack such that a thermal conditioning fluid can flow through the cavity of the battery pack to create a temperature gradient between the first component and the second component for weakening the adhesive bond during servicing of the battery pack.

13. The battery pack of claim 12, wherein, The first component comprises a cell sub-assembly, the cell sub-assembly 10 comprising: at least one battery cell; a flexible cell carrier having a first side secured to each of the at least one battery cell, and having a second side secured to the second component by the adhesive bond; and a load attachment point extending from a first end of the cell carrier, such that when a load is applied to the load attachment point, the flexible cell carrier is peeled from the second component starting from the first end.

14. The battery pack of claim 12 or claim 13, wherein, The battery pack further comprises a drain port for emptying the cavity in use, and the drain port is configured for flowing a thermal conditioning fluid therethrough during servicing of the battery pack.

15. A vehicle comprising the battery pack of any one of claims 12-14.

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