Description:TECHNICAL FIELD
[0001] The present subject matter relates to an energy storage device. More particularly, heat dissipation in the battery modules is disclosed. The present application is a patent of addition with respect to the patent application number IN202241017709.
BACKGROUND
[0002] Existing research in battery technology is directed to rechargeable energy storage devices, such as sealed batteries, starved electrolyte batteries, lead/acid batteries. Rechargeable energy storage devices are commonly used as power sources in different applications, such as, vehicles and the like. However, the lead-acid batteries are heavy, bulky, have short cycle life, short calendar life, and low turn around efficiency, resulting in limiting the applications of the lead-acid batteries.
[0003] The problems associated with conventional energy storage devices including the lead-acid batteries, are overcome in lithium-ion batteries, as they provide an ideal system for high energy-density applications. Also, the lithium-ion batteries have advantages over conventional energy storage devices, such as improved rate capability, and safety of the system in which the battery is incorporated and the human handling it. Further, the rechargeable energy storage devices, such as lithium-ion batteries exhibit one or more beneficial characteristics which makes the lithium-ion batteries useable for battery powered devices. Firstly, for safety reasons, the lithium-ion battery is completely constructed using solid components, while still retaining flexibility and compactness. Secondly, the energy storage devices including the lithium-ion battery exhibit similar conductivity characteristics like that of primary batteries with liquid electrolytes, i.e., deliver high power and energy density with low rates of self-discharge. Thirdly, the lithium-ion battery is capable of being readily manufactured in a reliable and cost-efficient manner. Also, the energy storage devices including the lithium-ion batteries can maintain a necessary minimum level of conductivity at sub-ambient temperatures that makes the lithium-ion batteries reliable in varied operating temperatures.
[0004] In a known structure for the energy storage device, one or more energy storage cells including lithium-ion battery cells are disposed in at least one holder structure in series and parallel combinations, using at least one interconnecting structure. The interconnecting structure is adapted for electrically interconnecting the energy storage cells with a battery management system (BMS).
BRIEF DESCRIPTION OF DRAWINGS
[0005] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0006] Figure. 1 exemplarily illustrates an elevation view of general assembly of energy storage device.
[0007] Figure. 2 exemplarily illustrates a top perspective exploded view of the energy storage device.
[0008] Figure. 3 exemplarily illustrate an exploded perspective view of sub-assembly of energy storage device.
[0009] Figure. 4 exemplarily illustrates a top perspective view of an energy storage module.
[00010] Figure. 5 exemplarily illustrates an inner side of at least one part of the holder.
[00011] Figure. 6 exemplarily illustrates a front view of the cell holder, in accordance with an embodiment.
[00012] Figure. 7 exemplarily illustrates an exploded perspective view of the sub-assembly of the energy storage device showing the energy storage module.
[00013] Figure. 8 exemplarily illustrates a perspective view of the energy storage module with casing, in accordance with an embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[00014] Energy storage device may be used in driving electric vehicles or hybrid electric vehicles. The energy storage device comprises one or more energy storage cells, such as, lithium-ion battery cells enclosed within a casing.
[00015] In such energy storage devices, failing of one cell can cause damage to other cells as well which has the potential to affect the safety and performance of the complete energy storage device. Cells dissipate heat while charging and discharging process of the cell i.e., heat is produced by each cell when the energy is stored and when energy is consumed. This may be due to reasons such as overcharging, frozen electrolyte, damaged cells, low electrolyte level, etc. Damage caused to electrodes during assembly, manufacturing and during tab welding creates a risk of short circuit in the cells, causing cell failure. Therefore, when cell failure occurs due to short circuits, the cells typically release considerable quantity of hot gases. Since usually the energy storage device includes packs of multiple cells stacked together, the hot gases generated due to short circuit of a cell have the capability of impacting the integrity of the neighbouring cells in the energy storage device and cause substantial damage to the other functional cells along with other critical components, placed in proximity of the failed cells.
[00016] The heat thus generated during charging/discharging process, short circuit of the cell and during operation of the energy storage device can cause thermal runaway having potential of damaging the complete energy storage device. Thermal propagation between the cells is to be avoided to contain the failure of the cells within itself without damaging the whole neighbouring cells and burning the energy storage device and the vehicle. There is also a need to keep lower the overall temperature of the energy storage modules in an energy storage device to avoid failures in the cells. Poor thermal management inside lithium-ion battery packs, especially for electric vehicles (EVs) have become an emerging issue, mainly because of fire hazard incidents.
[00017] Conventionally some known arts suggest usage of a single medium of thermal management within a battery pack. Such energy storage devices with single medium of thermal management, employ a phase change material or gap filler or thermal conducting paste or thermal pads as the single medium. Some known arts suggest usage of one or more internal fins and heat sinks along with a phase change material for thermal management of the energy storage device. Similarly, some other known arts, suggest usage of a phase change material filled in between the cells of the energy storage modules, along with a heat transfer structure in between the adjacent energy storage modules within a modular structure. However, the existing known arts fail to provide a mechanism of thermal management of an energy storage device, using more than one medium for passive cooling of the energy storage device.
[00018] There exists a need for providing an energy storage device capable of avoiding thermal propagation between cells and providing better cooling of the energy storage modules.
[00019] The present subject matter is an improvement over the patent application number IN202241017709, herein called as ‘the application’. The application discloses about an energy storage device, comprising a casing with one or more energy storage module. The one or more energy storage module includes one or more cells configured to be disposed within one or more holder. The one or more holders includes one or more parts, for example a first part and a second part. Each of the one or more part of the one or more holders includes one or more accommodating feature. The one or more accommodating feature is dedicated for accommodating at least one end of each cell of the one or more energy storage device and the accommodating feature includes a shielded portion and an open portion. The negative terminal of each cell is provided on the outer periphery of least one end of each cell, and the positive terminal is encircled by the negative terminal.
[00020] The subject matter in the application aid in providing safe and secured packaging of the cells within a holder of an energy storage device. This is because the accommodating feature of the holder, always ensures that, the contact between the positive terminal and negative terminal of the cell is eliminated. Furthermore, the shielded portion prevents welding of the engaging portion of the interconnector, on the wrong area of the cell. Altogether, it aids in eliminating the risk of short circuiting.
[00021] However, capability of avoiding thermal propagation between cells while at the same time providing better cooling of the energy storage modules by allowing thermal propagation between the energy storage modules and the casings is not achieved in this arrangement.
[00022] Hence, there is a need of addressing the above circumstances and problems of the known arts.
[00023] The present subject matter has been devised in view of the above circumstances as well as solving other problems of the known art. To prevent occurrences of such above stated untoward events, in the existing structures of the energy storage device, a thermally insulative material needs to be provided between the cells, and to remove the heat generated from the cells and a thermally conductive material needs to be placed between the cell and the casing for passive cooling.
[00024] The present subject matter discloses in an embodiment, an energy storage device comprising a casing, and one or more energy storage module. The one or more energy storage module includes one or more cells configured to be disposed within one or more holder.
[00025] The one or more holders includes one or more parts, for example a first part and a second part. Each of the one or more part of the one or more holders includes one or more accommodating feature.
[00026] The one or more accommodating feature is dedicated for accommodating at least one end of each cell of the one or more energy storage module, ensuring that the contact between a positive terminal and a negative terminal of each cell of the one or more cells is being eliminated.
[00027] The one or more energy storage module is to be sealed completely from all sides leaving a small opening on the top for filling of encapsulant. The sealing is obtained by using liquid sealant on all the edges between the cell holder top and cell holder bottom. In addition to this liquid sealant is to be applied on the cell holder ring (accommodating feature) feature circumference for each cell to seal all the openings on the cell side at both positive and negative terminals ensuring complete sealing of the energy storage module. A gap filler (thermal interface material) / a thermally conductive paste is applied on both the sides of the energy storage module after which casing is assembled. The gap between the energy storage module and the casing should be minimum as per the characteristic of the gap filler (thermal interface material) to function effectively.
[00028] The dual thermal management using encapsulant and gap filler provides heat takeaway from the energy storage modules to the casing through the gap filler (thermal interface material) and the encapsulant provides protection by avoiding thermal propagation between the adjacent cells if any one cell goes into thermal runaway thereby avoiding thermal propagation and subsequent burning of battery pack.
[00029] Exemplary embodiments detailing features regarding the aforesaid and other advantages of the present subject matter will be described hereunder with reference to the accompanying drawings. Various aspects of different embodiments of the present invention will become discernible from the following description set out hereunder. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter.
[00030] Figure 1 exemplarily illustrates a side perspective view of an energy storage device 100, in accordance with an embodiment of the present subject matter. Herein energy storage device 100 includes an energy storage device 100. The energy storage device 100 comprises of one or more energy storage module 100a, also called as a energy storage module 100a (shown in Figure 3) and a casing 101. The casing 101 protects the one or more energy storage module 100a from external factors, such as environmental factors, and prevents the one or more energy storage module 100a from getting damaged. The one or more energy storage module 100a, includes one or more cells 105 (shown in Figure 2) disposed in one or more holder 104 (shown in fig.3) to hold the cells 105 together in a pre-defined position. The holder 104 holds the individual cells 105 and the joint output of all the cells 105 are transferred to a channel through bus bars. The holder 104 also ensures maintaining the required cell 105 arrangement and adequate cell 105 spacing. The one or more cells 105 provide the electric energy to drive a vehicle (not shown).
[00031] The holder 104 is provided with one or more voltage sensing points 112 (shown in Figure 2) for one or more interconnectors 106 (shown in Figure 2) to be placed. The one or more interconnectors 106 are used to make electrical connection between the one or more cells 105 by means of the one or more voltage sensing points 112. The one or more cells 105 are welded to the interconnector 106 to form the energy storage module 100a. The one or more interconnectors 106 are placed above the one or more energy storage module 100a and the voltage sensing points 112 are provided on the energy storage module 100a to hold the one or more interconnectors 106 in place.
[00032] Figure 2 exemplarily illustrates a top perspective exploded view of the energy storage device 100, in accordance with an embodiment. In the present embodiment, the casing 101 includes a first casing 101a, a second casing 101b, a top casing 101c, and a bottom casing 101d. The first casing 101a is configured to support a front portion of the one or more cells 105. The second casing 101b is configured to support a back portion of the one or more cells 105. The top casing 101c is configured to cover the energy storage module 100a from a top portion of the energy storage module 100a. The bottom casing 101d provides is configured to support the one or more energy storage modules 100a from a bottom portion. In an embodiment, the one or more casing 101 can be an aluminium casing. In the present embodiment, one or more energy storage module management system is detachably attached within the top casing 101c of the energy storage module 100a with one or more fastening means (not shown). An secondary port 118 and a socket 120 are provided in the top casing 101c to bring out the connection to the outside of the energy storage device 100 from the energy storage module management system.
[00033] Figure 3 exemplarily illustrates a perspective exploded view of the energy storage device 100, in accordance with an embodiment.
[00034] Figure 4 exemplarily illustrates a top perspective view of a energy storage module 100a, in accordance with an embodiment of the present subject matter. The energy storage module 100a includes the holder 104. The holder 104 is provided with one or more voltage sensing points 112 (shown in Figure 2) for one or more interconnectors 106 (shown in Figure 2) to be placed. The holder 104 includes one or more parts, i.e., a first part 104a, and a second part 104b. Both the first part 104a and the second part 104b align together in parallel and hold the cells 105 (shown in Figure 2) therebetween. The holder 104 is provided with one or more encapsulant disposing port 123, herein called as a primary port 123.
[00035] Figure 5 exemplarily illustrates an inner side of at least one part (104a, 104b) of the holder 104, in accordance with an embodiment of the present subject matter. Each of the holder 104 includes one or more accommodating feature 107 dedicated for accommodating at least one end of each cell 105 of the energy storage module 100a. The present subject matter aid in providing safe and secured packaging of the cells within the holder 104 of the energy storage device 100. This is because the accommodating feature 107 of the holder 104, always ensures that, the contact between a positive terminal 105b (shown in Figure 5) and a negative terminal 105a (shown in Figure 5) of the cell 105 is eliminated.
[00036] In an embodiment, the accommodating feature 107 is a ring-shaped structure.
[00037] Each part (104a, 104b) of the holder 104 includes a plurality of first mounting provisions 109, and a plurality of second mounting provisions 110. The plurality of first mounting provisions 109, and the plurality of second mounting provisions 110 together aid in aligning the two parts (104a, 104b) of the holder 104 in parallel. The plurality of first mounting provisions 109, and the plurality of second mounting provisions 110 ensure tight packaging of the cells 105 within the two parts (104a, 104b) of the holder 104.
[00038] Each accommodating feature 107 includes an open portion 107a and a shielded portion 107b. At least one end of each cell 105 of the energy storage device 100, includes the negative terminal 105a (shown in Figure 6) and the positive terminal 105b (shown in Figure 6). The negative terminal 105a is usually present on the outer periphery of least one end of each cell 105. The positive terminal 105b is encircled by the negative terminal 105a. The shielded portion 107b covers the negative terminal 105a of the cell. The open portion 107a acts as an opening to expose the positive terminal 105b of the cell 105. Between each accommodating feature 107 of the one of the parts (104a, 104b), a plurality of inward protruded restrictors 107c are provided. The open portion 107a, the shielded portion 107b, and the restrictors 107c, together function as a locator for each cell 105 and thus aid in easy assembly of the cells 105 within the holder 104. These restrictors 107c ensures that each cell 105 is restricted to respective accommodating feature 107 of each part (104a, 104b) of the holder 104. Thus, ensuring tight packaging of the cells 105 within the two parts (104a, 104b) of the holder 104.
[00039] Each engaging portion 106a of the interconnector 106 is welded on the positive terminal 105b of each cell 105, through the open portion 107a of the accommodating feature 107. The exposed negative terminal 105a of each cell 105 is always shielded by the shielded portion 107b of the accommodating feature 107. The shielded portion 107b aids in eliminated the risk of short circuiting by welding of the engaging portion 106a of the interconnector 106, on the wrong area of the cell 105. Furthermore, because of safe and secured packaging, the present subject matter provides a durable energy storage device 100.
[00040] Since the shielded portion 107b of the accommodating feature 107, secures the negative terminal 105a (not shown) of each cell 105 there within. This ensures that the interconnector 106 is welding on the positive terminal 105b (not shown) only. Thus, eliminating the risk of short circuit.
[00041] Figure 6 exemplarily illustrates a front view of the cell holder 104, in accordance with an embodiment. A sealant 121 is applied on the one or more cell holders accommodating feature 107 and over the periphery of the cell holder top and bottom at all the designated areas as shown in the figure. Then the cells are placed at the respective area and the cell holder parts (104a, 104b) are closed with the aid of a plurality of first mounting provisions 109, and a plurality of second mounting provisions 110. The one or more interconnectors 106 (shown in Figure 2) are then placed on the one or more voltage sensing points 112 (shown in Figure 2) to complete the energy storage module 100a.
[00042] In an embodiment, the sealant 121 is a liquid sealant.
[00043] After the module assembly is completed, encapsulant 122 is disposed to the energy storage module 100a through the one or more encapsulant disposing port 123 on the holder 104 as shown in Fig 4. The sealant between the cell holders and between the cells and the cell holders restrict the flow of the encapsulant and keeps it inside the battery module where it is intended and encapsulant does not leak outside the encapsulant protects the cells from thermal propagation between the cells when a cell goes into thermal runaway.
[00044] Figure 7 exemplarily illustrates an exploded perspective view of the sub-assembly of the energy storage device 100 showing the energy storage module 100a, in accordance with an embodiment. A gap filler 124 is applied onto sides of energy storage module 100a to occupy the space between the energy storage module 100a and the first casing 101a and second casing 101b in assembled setup. This ensures that heat is propagated between the energy storage modules 100a and the casings 101 so that thermal management of the the energy storage device 100 is ensured.
[00045] Figure 8 exemplarily illustrates an perspective view of the energy storage module 100a with casing, in accordance with an embodiment.
[00046] In an embodiment, the gap filler 124 is a thermal interface material.
[00047] In an embodiment, the gap filler 124 is a thermal conductive paste.
[00048] The sealed battery module which prevents the leakage of the encapsulant 121 further prevents contact between the encapsulant and the gap filler 124. Dual thermal management in the energy storage device 100 is obtained as the encapsulant 124 protects the cells from thermal propagation between the cells when a cell goes into thermal runaway and heat is propagated between the cells and the casing 101 for thermal management.
 
LIST OF REFERENCE NUMERALS

100: Battery pack, energy storage device
100a: Battery module, energy storage module
101: Casing
101a: First casing
101b: Second casing
101c: Top casing
101d: Bottom casing
104: Holder
104a: A first part
104b: A second part
105: Cells
105a: Negative terminal
105b: Positive terminal
106: Interconnectors
106a: Engaging portion
107: Ring feature
107a: Open ring portion
107b: Covered ring portion
107c: Restrictors
108: Base member
110: Snap fitting provisions
109: Fastening provisions
112: Voltage sensing points
118: Secondary port
120: Socket
121: Liquid sealant
122: Encapsulant
123: Primary port
124: Gap filler
, Claims:Claims:
We claim,

1. An energy storage device (100) comprising:
a casing (101); and
one or more energy storage module (100a), said one or more energy storage module (100a) comprises,
one or more cells (105) configured to be disposed within one or more holder (104), wherein said one or more holder (104) includes one or more accommodating feature (107), said one or more accommodating feature (107) enable securing of at least one end of each cell of said one or more cells (105) of said one or more energy storage module (100a),
an encapsulant (122), wherein the encapsulant (122) being disposed in said energy storage module (100a) to restrict thermal propagation between said one or more cells (105), and
a gap filler, wherein said gap filler (124) being applied on one or more sides of the energy storage module (100a) to occupy space between said energy storage module (100a) and at least one of a first casing (101a) and a second casing (101b) of said casing (101) in an assembled condition.
2. The energy storage device (100) as claimed in claim 1, wherein at least one layer of a sealant (121) being applied on at least one of said one or more accommodating feature (107) and the periphery of said one or more holder (104), restricting said encapsulant (122) within said energy storage module (100a).
3. The energy storage device (100) as claimed in claim 1, wherein said one or more holder (104) includes one or more primary port (123).
4. The energy storage device (100) as claimed in claim 3, wherein said one or more primary port (123) being provided for disposing said encapsulant (122) within said energy storage module (100a).
5. The energy storage device (100) as claimed in claim 1, wherein said gap filler (124) being capable of occupying empty space in between said energy storage module (100a) and at least one of said first casing (101a) and said second casing (101b) in an assembled condition.
6. The energy storage device (100) as claimed in claim 1, wherein said gap filler (124) being a thermal interface material.
7. The energy storage device (100) as claimed in claim 1, wherein said gap filler (124) being a thermal conductive paste.
8. The energy storage device (100) as claimed in claim 1, wherein said sealant (121) being a liquid sealant.
9. The energy storage device (100) as claimed in claim 1, wherein said one or more accommodating feature (107) being a ring-shaped structure.
10. The energy storage device (100) as claimed in claim 1, wherein at least one end of each cell (105) of said energy storage device (100), including a positive terminal (105b) and a negative terminal (105a).
11. The energy storage device (100) as claimed in claim 10, wherein said one or more accommodating feature (107) being configured to eliminate contact between said positive terminal (105b) and said negative terminal (105a) of said each cell (105) of said one or more cells (105).
12. The energy storage device (100) as claimed in claim 1, wherein each part of said one or more parts (104a, 104b) of said holder (104) includes a plurality of fastening provisions (109), and a plurality of snap 20 fitting provisions (110), wherein said plurality of fastening provisions (109), and said plurality of snap fitting provisions (110) together aid in aligning said one or more parts (104a, 104b) of said holder (104) in parallel.
13. The energy storage device (100) as claimed in claim 1, wherein said one or more cells (105) being electrically connected to one or more interconnectors (106), by means of one or more voltage sensing points (112) provided on said holder (104).
14. The energy storage device (100) as claimed in claim 1, wherein said casing (101) includes a first casing (101a), a second casing (101b), a top casing (101c), and a bottom casing (101d), wherein, said first casing (101a) being configured to support a front portion of said one or more cells (105), said second casing (101b) being configured to support a back portion of said one or more cells (105), said top casing (101c) being configured to cover said energy storage module (100a) from a top portion of said energy storage module (100a), and said bottom casing (100d) being configured to support said energy storage module (100a) from a bottom portion.
15. The energy storage device (100) as claimed in claim 1, wherein said casing (101) being an aluminium casing.
16. The energy storage device (100) as claimed in claim 1, wherein said one or more holder (104) includes a first part (104a), and a second part (104b), wherein both said first part (104a), and said second part (104b) align together in parallel, and hold said one or more cells (105) there between.
17. The energy storage device (100) as claimed in claim 10, wherein said negative terminal (105a) being on the outer periphery of least one end of each cell (105) and said positive terminal (105a) being encircled by said negative terminal (105a).
18. The energy storage device (100) as claimed in claim 1, wherein said one or more accommodating feature (107) includes a shielded portion (107b) and an open portion (107a).
19. The energy storage device (100) as claimed in claim 18, wherein said shielded portion (107b) covers a negative terminal (105a) of said each cell (105) within said energy storage device (100).
20. The energy storage device (100) as claimed in claim 18, wherein said open portion (107a) being an opening, exposing a positive terminal (105b) of said each cell (105) within said energy storage device (100).
21. The energy storage device (100) as claimed in claim 1, wherein each accommodating feature (107) of said one or more parts (104a, 104b), includes a plurality of inward protruded restrictors (107c).
22. The energy storage device (100) as claimed in claim 18, wherein said open portion (107a), said shielded portion (107b), and said restrictors (107c), together function as a locator for each cell (105) and thus aid in easy assembly of the one or more cells (105) within a holder (104).
23. The energy storage device (100) as claimed in claim 13, wherein each engaging portion (106a) of said interconnector (106) being welded on a positive terminal (105b) of said each cell (105) through an open portion (107a) of an accommodating feature (107).