FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10; Rule 13)
TITLE OF THE INVENTION “CONTROLLING TEMPERATURE OF A VEHICLE BATTERY”
APPLICANT(S)
TATA MOTORS LIMITED
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001,
Maharashtra, India.
Nationality Indian.
Tata Motors European Technical Centre plc
18 Grosvenor Place, London,
SW1X 7HS, United Kingdom,
Nationality United Kingdom.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[0001] The present invention relates to a vehicle battery, and more specifically related to controlling temperature of a vehicle battery.
BACKGROUND OF THE INVENTION
[0002] A vehicle may include a battery to power one or more electrical loads in the vehicle. For example, the battery may power a traction motor that drives the vehicle. The temperature of the battery may impact the performance, life, and safety of the battery. For example, if the battery is operated at a temperature higher than a particular temperature for a prolonged period of time, the battery may get excessively heated, which may cause a high power loss and may also cause potential safety hazards, such as a thermal runaway.
[0003] To maintain the temperature of the battery within a particular range, a coolant may be supplied around cells of the battery. The coolant may cool or heat the cells depending on the requirement, thereby maintaining/bringing the temperature of the cells, and consequently the battery, within the range. For instance, if the cells are to be cooled, coolant of a low temperature may be flown around the cells, thereby reducing their temperatures. Similarly, if the cells are to be heated, coolant of a high temperature may be flown around the cells.
[0004] Although the flow of coolant cools/heats the cells, the cooling/ heating of the different cells may be different. Accordingly, the temperatures of different cells may significantly differ from each other. For example, if the coolant of a low temperature flows from a first end of the battery to a second end of the battery to cool the cells, the temperature of the coolant progressively increases as it moves away from the first end due to absorption of heat from the cells with which the coolant came into contact. The increase in the temperature of the coolant reduces

its cooling effect as it approaches the second end. Thus, the cells near the second end may be hotter than those near the first end.
SUMMARY OF THE INVENTION
[0005] A thermal management system (TMS) for a battery of a vehicle includes a bi-directional (BD) valve and a temperature control unit (TCU). The BD valve is to be coupled to a first end and to a second end of the battery and is to control flow of a coolant through the battery between the first end and the second end. A first position of the BD valve allows the coolant to flow from the first end to the second end and a second position of the BD valve allows the coolant to flow from the second end to the first end. The TCU is to monitor temperature of at least a part of the battery, and is to control position of the BD valve to the first position or the second position based on the temperature, to maintain a substantially uniform temperature distribution across the battery.
BRIEF DESCRIPTION OF THE DRAWING(S)
[0006] The features, aspects, and advantages of the subject matter will be better understood with regard to the following description, and accompanying figures. The use of the same reference number in different figures indicates similar or identical features and components.
[0007] Fig. 1 illustrates a vehicle, according to an implementation of the present subject matter.
[0008] Fig. 2(a) illustrates a bi-directional (BD) valve when it is in a first position, according to an implementation of the present subject matter.
[0009] Fig. 2(b) illustrates a BD valve when it is in a second position, according to an implementation of the present subject matter.

[0010] Fig. 3(a) illustrates a battery when a coolant flows through the battery from a first end to a second end of the battery, according to an implementation of the present subject matter.
[0011] Fig. 3(b) illustrates a battery when a coolant flows through the battery from a second end to a first end of the battery, according to an implementation of the present subject matter.
[0012] Fig. 4 illustrates a vehicle in which temperature of a battery is controlled using a BD valve, according to an implementation of the present subject matter.
[0013] Fig. 5 illustrates a vehicle in which temperature of a battery is controlled, according to an implementation of the present subject matter.
[0014] Fig. 6 illustrates a method for controlling temperature of a battery of a vehicle using a BD valve, according to an implementation of the present subject matter.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present subject matter relates to controlling temperature of a vehicle battery. Using techniques of the present subject matter, a substantially uniform temperature distribution can be achieved and maintained in the vehicle battery, also referred to as a battery.
[0016] In accordance with an implementation of the present subject matter, a bi-directional (BD) valve is coupled to a first end and to a second end of the battery. Through the BD valve, a coolant can flow to the battery and flow between the first end and the second end. The flow of the coolant through the battery between the first and second ends cools or heats cells of the batteries depending on the

requirement. A position of the BD valve can be adjusted to control a direction of flow of the coolant through the battery. For example, a first position of the BD valve allows the coolant to flow through the battery from the first end to the second end, while a second position of the BD valve allows the coolant to flow through the battery from the second end to the first end.
[0017] A temperature control unit (TCU) monitors temperature of at least a part of the battery. For example, the TCU may monitor temperatures of cells at a plurality of locations of the battery, such as a cell closest the first end and a cell closest to the second end. Based on the monitored temperature, the position of the BD valve may be controlled to be either the first position or the second position. The control of the position of the BD valve based on the monitored temperature may enable achieving and maintaining a substantially uniform temperature distribution across the battery, as will be explained below with the help of an example:
[0018] Consider that the BD valve is at the first position, and a cooled coolant flows from the first end to the second end of the battery to cool the cells of the battery. Consider also that the temperature of the cell closest to the second end is higher than that of the cell closest to the first end by a threshold temperature value, such as 5° C. In such a case, the TCU may infer that the cells closer to the second end are not getting sufficiently cooled because of heating of the coolant by the time it reaches near the second end. Accordingly, the TCU may change the position of the BD valve to the second position. Such a change causes the cooled coolant to first pass through the cells closer to the second end, thereby enabling their better cooling. In this manner, by changing the position of the BD valve based on the temperatures at various regions of the battery, the direction of coolant flow can be reversed. The reversal reduces the differences in temperatures of the various regions of the battery. Thus, a temperature gradient within the battery may be maintained at a reduced level.

[0019] The implementations herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting implementations that are illustrated in the accompanying drawings and detailed in the following description. It should be understood, however, that the following descriptions, while indicating preferred implementations and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the implementations herein without departing from the spirit thereof, and the implementations herein include all such modifications. The examples used herein are intended merely to facilitate an understanding of ways in which the implementations herein can be practiced and to further enable those skilled in the art to practice the implementations herein. Accordingly, the examples should not be construed as limiting the scope of the implementations herein.
[0020] Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the implementations herein. Also, the various implementations described herein are not necessarily mutually exclusive, as some implementations can be combined with one or more other implementations to form new implementations.
[0021] Referring now to the drawings, and more particularly to Figs. 1 through 6, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred implementations. Further, for the sake of simplicity, and without limitation, the same numbers are used throughout the drawings to reference like features and components. The implementations herein will be better understood from the following description with reference to the drawings.
[0022] Fig. 1 illustrates a vehicle 100, according to an implementation of the present subject matter. The vehicle 100 may be, for example, a passenger vehicle (PV), such as a car, a commercial vehicle (CV), such as a truck, or another class of

vehicle. The vehicle 100 may include a battery 102 to power various electrical and electronic components of the vehicle 100. In an example, the vehicle 100 may be an electric vehicle (EV), and the battery 102 may power a traction motor (not shown in Fig. 1) that drives the vehicle 100. A temperature of the battery 102 may have to be maintained within an optimal range, such as 20-35° C, to ensure a satisfactory performance and a long life of the battery 102. Further, operating the battery 102 for long periods of time more than a maximum limit, such as 55° C, or less than a minimum limit (which may depend on the electrodes and electrolyte used in the battery 102), such as 5° C, may significantly impact the life and performance of the battery 102.
[0023] To maintain the temperature of the battery 102 within an acceptable range, the vehicle 100 may include a thermal management system TMS 104. The thermal management system 104 may circulate a coolant (not shown in Fig. 1) through the battery 102. The coolant may be air or a liquid. The coolant may be cooled or heated before circulating it depending on whether the battery 102 is to be cooled or heated. For example, if the battery 102 is to be cooled, the coolant may be cooled before flowing it through the battery 102. To cool the coolant, a radiator 106 and a chiller 107 may be utilized. Further, if the battery 102 is to be heated, the coolant may be heated before flowing it through the battery 102. To heat the coolant, a heater 108 may be utilized. The TMS 104 may include a pump 110 to pump the coolant to cause the flow of the coolant through the battery 102. Although the TMS 104 is shown to have a single pump, multiple pumps may be provided at various positions of the TMS 104 to allow flow of the coolant to the battery 102.
[0024] The coolant may flow through the battery 102 between a first end 112 and a second end 114 of the battery 102. For example, the coolant may enter the battery 102 through the first end 112 and exit through the second end 114 or vice-versa, thereby ensuring that all cells (not shown in Fig. 1) in the battery 102 come in contact with the coolant before the coolant leaves the battery 102. The first end 112

and the second end 114 may be, for example, ends in the length, width, or height directions of the battery 102.
[0025] The TMS 104 may control a direction of flow of the coolant through the battery 102. To this end, the TMS 104 may include a bi-directional (BD) valve 116 and a temperature control unit (TCU) 118. The BD valve 116 may be coupled to the battery 102 and may allow flow of the coolant to the battery 102 through itself. For instance, the BD valve 116 may be coupled to the pump 110 to receive the coolant pumped by the pump 110 and may supply the pumped coolant to the battery 102. Further, the BD valve 116 may receive the coolant that has flown through the battery 102, and may supply the received coolant back to the pump 110. In an example, as illustrated, the coolant may flow back to the pump 110 through the radiator 106. The BD valve 116 may be coupled to the first end 112 and the second end 114 of the battery 102 to supply coolant to, and to receive coolant from the battery 102.
[0026] The BD valve 116 may allow flow of the coolant to the battery 102 in two opposite directions. In a first direction (not shown in Fig. 1), the coolant from the pump 110 may flow through the BD valve 116 to the first end 112, flow through the battery 102 from the first end 112 to the second end 114, and flow from the second end 114 back to the BD valve 116. The coolant flows from the BD valve 116 to the first end 112 through the chiller 107 (if the battery 102 is to be cooled) or through the heater 108 (if the battery 102 is to be heated). In a second direction (not shown in Fig. 1), the coolant from the pump 110 may flow through the BD valve 116 to the second end 114, flow through the battery 102 from the second end 114 to the first end 112, and flow from the first end 112 back to the BD valve 116. The coolant may flow from the second end 114 to the BD valve 116 through the chiller 107 or the heater 108. The flow through the chiller 107 and the heater 108 may be controlled using a valve 119, for example, by the TCU 118.

[0027] The direction of flow of the coolant may be controlled by controlling a position of the BD valve 116. For instance, the coolant may flow in the first direction for a first position of the BD valve 116, and the coolant may flow in the second direction for a second position of the BD valve 116. The position of the BD valve 116 may be controlled by the TCU 118 based on temperature of at least a part of the battery 102, as will be explained below with the help of an example:
[0028] The TCU 118 may monitor temperatures at a plurality of locations of the battery 102. The plurality of locations may include, for example, a point (not shown in Fig. 1) near the first end 112 and a point (not shown in Fig. 1) near the second end 114. For instance, the temperature of a cell closer to the first end 112 than to the second end 114 (e.g., the cell closest to the first end 112) and the temperature of a cell closer to the second end 114 than to the first end 112 (e.g., the cell closest to the second end 114) may be monitored. The cell closer to the first end 112 than to the second end 114 may be referred to as a first cell and its temperature may be referred to as a first temperature. Further, the cell closer to the second end 114 than to the first end 112 may be referred to as a last cell and its temperature may be referred to as a second temperature.
[0029] The TCU 118 may determine if a difference between the first temperature and the second temperature is high, such as greater than a threshold. The difference indicates a temperature gradient existing in the battery 102. The threshold may be preconfigured in the TCU 118 or in a memory (not shown in Fig. 1) associated with the TCU 118. The threshold may be determined by a designer of the battery 102 based on knowledge of the temperature gradient that may be detrimental to the health of the battery 102. In an example, the threshold may be 5° C.
[0030] If the difference is high, the TCU 118 may infer that the regions of the battery 102 that are near the downstream end in the flow direction of the coolant are not getting sufficiently cooled or heated, as per the requirement. For instance, consider that the battery 102 is to be cooled by the coolant and that the coolant is

flowing in the first direction, i.e., from the first end 112 to the second end 114. In such a case, if the second temperature is higher than the first temperature by more than the threshold, the TCU 118 may infer that the coolant gets significantly hotter by the time it reaches near the second end 114, causing a reduced cooling of the cells near the second end 114.
[0031] The TCU 118 may change the position of the BD valve 116 if the difference between the first temperature and the second temperature exceeds the threshold, to prevent the temperature difference from increasing further. For example, if, for the first position of the BD valve 116 (which causes the coolant to flow from the first end 112 to the second end 114), the second temperature is higher than the first temperature by more than the threshold, the TCU 118 may change the position of the BD valve 116 to the second position. Such a change in position causes the coolant to enter the battery 102 through the second end 114 and exit through the first end 112. Thus, the coolant is cooler near the second end 114 than it is near the first end 112. Accordingly, a greater cooling of the cells near the second end 114 is achieved, thereby reducing the difference between the first temperature and the second temperature. Subsequently, when the first temperature becomes higher than the second temperature by more than the threshold, the TCU 118 may change the position of the BD valve 116 to the first position. In this manner, the TCU 118 may keep changing the position of the BD valve 116, causing reversals of flow direction of the coolant, depending on the temperatures near the first end 112 and near the second end 114, to maintain the temperature difference within the threshold. Thus, the present subject matter enables maintaining substantially a uniform temperature distribution across the battery 102.
[0032] Although the control of position of the BD valve 116 is explained as being performed based on a difference in temperatures near the first end 112 and the second end 114, the control may be performed based on other temperatures of the battery 102. For example, the position of the BD valve 116 may be changed based on a maximum temperature within the battery 102, a minimum temperature within

the battery 102, an average temperature within the battery 102, or any combination of the temperature difference, the maximum temperature, the minimum temperature, and the average temperature. The temperature based on which the position of the BD valve 116 is to be changed may be monitored by the TCU 118. Further, in an example, the control of position of the BD valve 116 may be based on a rate of change of temperature of the battery 102. For instance, the rate of increase in temperature of a particular location of the battery 102 may be monitored, and the position of the BD valve 116 may be changed if the rate of increase is more than a threshold. Further, in an example, the control of position of the BD valve 116 may be based on a predicted rate of change of temperature of the battery 102. For instance, if a high rate of increase of battery temperature is predicted (based on a high current demand), the position of the BD valve 116 may be adjusted.
[0033] During reversals in the flow direction of the coolant, the pressure in coolant pipes (illustrated as block arrows in Fig. 1), through which the coolant flows to and from the battery 102, may rise. The phenomenon of rise in the pressure due to reversal in fluid direction is generally referred to as water hammer. Such a rise in the pressure may damage the coolant pipes. To prevent the damage to the coolant pipes, the TMS 104 may include one or more hydraulic accumulators (also referred to as water hammer arrestors), such as the hydraulic accumulators 120, 122, and 124. As will be understood, a hydraulic accumulator may include a chamber (not shown in Fig. 1) that may act as a buffer for holding coolant during reversal of the flow of the coolant. Upon the reversal, once the flow of the coolant through the coolant pipes has stabilized, the chamber may become substantially empty. The number and positions of hydraulic accumulators in the TMS 104 may be decided to prevent the occurrence of water hammer in the TMS 104. In an example, a first hydraulic accumulator 120 is disposed between the BD valve 116 and the first end 112, a second hydraulic accumulator 122 is disposed between the BD valve 116 and the second end 114, and a third hydraulic accumulator 124 is disposed between the radiator 106 and the pump 110.

[0034] Fig. 2(a) illustrates the BD valve 116 when it is in the first position, according to an implementation of the present subject matter. The BD valve 116 may include a plurality of ports through which the coolant can enter or exit the BD valve 116. The plurality of ports includes a first port 202, a second port 204, a third port 206, and a fourth port 208. The BD valve 116 may be coupled to the pump 110 through the first port 202, coupled to the first end 112 through the second port 204, coupled to the second end 114 through the third port 206, and coupled to the radiator 106 through the fourth port 208. Between the second port 204 and the first end 112, the chiller 107 and the heater 108 may be disposed, so that the coolant flows between the first end 112 and the BD valve 116 through the chiller 107 or the heater 108. The pump 110, the first end 112, the second end 114, the radiator 106, the chiller 107, and the heater 108 are not shown in Fig. 2(a).
[0035] The BD valve 116 may also include a spool 210. A position of the spool 210 within the BD valve 116 can be varied. The position of the spool 210 dictates the direction of flow of the coolant. For instance, for a first position of the spool 210, which is illustrated in Fig. 2(a) and which is also referred to as the first position of the BD valve 116, the coolant entering the BD valve 116 through the first port 202 from the pump 110 is directed to the second port 204. The coolant then exits the BD valve 116 through the second port 204 and flows to the first end 112 (through the chiller 107 or the heater 108), flows through the battery 102 and exits the battery 102 from the second end 114, and flows to the third port 206. The coolant, entering the BD valve 116 through the third port 206, exits the BD valve 116 through the fourth port 208 and reaches the radiator 106. The coolant then flows from the radiator 106 to the pump 110 for being pumped through the BD valve 116.
[0036] In this manner, for the first position of the spool 210 (and for the first position of the BD valve 116), the coolant flows through the battery 102 from the first end 112 to the second end 114. The coolant flows through the battery 102 in an opposite direction for a second position of the spool 210, as will be explained below:

[0037] Fig. 2(b) illustrates the BD valve 116 when it is in the second position, according to an implementation of the present subject matter. The second position of the BD valve 116 is achieved for a second position of the spool 210 as illustrated herein. For the second position of the spool 210, the coolant entering the BD valve 116 through the first port 202 from the pump 110 (not shown in Fig. 2(b)) is directed to the third port 206. The coolant then exits the BD valve 116 through the third port 206 and flows to the second end 114, flows through the battery 102 and exits the battery 102 from the first end 112, and flows to the second port 204 through the chiller 107 or the heater 108. The coolant, entering the BD valve 116 through the second port 204, exits the BD valve 116 through the fourth port 208 and reaches the radiator 106. In this manner, for the second position of the spool 210 (and for the second position of the BD valve 116), the coolant flows through the battery 102 from the second end 114 to the first end 112.
[0038] As explained above, the direction of flow of the coolant through the battery 102 for the second position of the BD valve 116 is opposite that for the first position of the BD valve 116. Accordingly, to control the direction of flow of the coolant through the battery 102, the TCU 118 (not shown in Fig. 2(b)) may control the position of the spool 210 in the battery 102. The manner in which the control of position of the spool 210 by the TCU 118 can be achieved will be understood by a person skilled in the art, and is not explained herein for the sake of brevity.
[0039] Although the BD valve is explained with reference to a spool valve, in some examples, other types of valves that can achieve a bi-directional flow of coolant can be utilized.
[0040] Fig. 3(a) illustrates the battery 102 when the coolant flows through the battery 102 from the first end 112 to the second end 114, according to an implementation of the present subject matter. The battery 102 may include a plurality of cells, such as cells 302-1, 302-2, …, 302-n. Of the plurality of cells, a first cell 302-1 may be closer to the first end 112 as compared to the other cells in

the battery 102 and farther from the second end 114 as compared to the other cells. Further, an nth cell 302-n may be closer to the second end 114 as compared to the other cells in the battery 102 and farther from the first end 112 as compared to the other cells. In an example, each cell may be a cylindrical cell. In another example, each cell may be a prismatic cell.
[0041] To cool the cells of the battery 102, a cooled coolant may be flown through the battery 102. While flowing through the battery 102, the cooled coolant may contact the outer surfaces of each cell in the battery 102, thereby absorbing their heat and cooling them. In an example, the coolant may enter the battery 102 through the first end 112, flow through the battery 102, and exit through the second end 114, as illustrated in block arrows. In accordance with the example, the coolant first contacts the outer surface of the first cell 302-1 as it enters the battery 102, then contacts the outer surface of a second cell 302-2, and so on. Finally, the coolant contacts the outer surface of nth cell 302-n (also referred to as the last cell) before exiting the battery 102. As the coolant moves through the battery 102, the temperature of the coolant progressively increases, as indicated by the progressive increase in the density of pixels within the block arrows in the right-hand side direction. Thus, the cooling of the nth cell 302-n may be lesser than that of the first cell 302-1, and the temperature of the nth cell 302-n may be more than that of the first cell 302-1.
[0042] The coolant flow from the first end 112 to the second end 114 may be achieved by controlling the BD valve 116 (not shown in Fig. 3(a)) to be in the first position of the BD valve 116. As explained earlier, the first position of the BD valve 116 is achieved by setting the spool 210 in its first position.
[0043] Fig. 3(b) illustrates the battery 102 when the coolant flows through the battery 102 from the second end 114 to the first end 112, according to an implementation of the present subject matter. In accordance with such a flow of the coolant, the cooled coolant first contacts the outer surface of the nth cell 302-n upon

entering the battery 102, then contacts the outer surface of the n-1st cell 302-n-1, then contacts the outer surface of the n-2nd cell 302-n-2, and so on. Finally, the coolant contacts the outer surface of the first cell 302-1 before exiting the battery 102 through the first end 112. Accordingly, the nth cell 302-n is cooled more than the first cell 302-1.
[0044] The coolant may flow from the second end 114 to the first end 112 when the BD valve 116 (not shown in Fig. 3(b)) is in its second position, as explained earlier. Further, the BD valve 116 may be deployed in its second position, for example, when the temperature of the nth cell 302-n is higher than that of the first cell 302-1 by more than a threshold temperature.
[0045] Fig. 4 illustrates a vehicle 400 in which temperature of a battery is controlled using a BD valve, according to an implementation of the present subject matter. Here, like components from Fig. 1 are illustrated with the same reference numbers as Fig. 1. The temperature of the battery 102 may be controlled by flowing the coolant through the battery 102 between its first and second ends 112 and 114. Further, the direction of flow of the coolant through the battery 102 can be reversed depending on temperature of at least a part of the battery 102, as explained with reference to Figs. 1-3(b).
[0046] In the vehicle 400, the TMS 104, which is used to control the temperature of the battery 102, may functionally interact with an HVAC (heating, ventilation, and air-conditioning) system (not shown in Fig. 4), which controls temperature of a passenger cabin (not shown in Fig. 4) of the vehicle 400. That is, the coolant that is used to control the temperature of the battery 102 may also be used to control the temperature of the passenger cabin. The HVAC system may include the radiator 106, the chiller 107, and a cabin heater 404. The chiller 107 may aid in cooling the passenger cabin when required. The cabin heater 404 may heat the passenger cabin when required.

[0047] In an implementation, the thermal energy required by the cabin heater 404 for heating the passenger cabin may be derived from the coolant that is heated by the battery 102. To this end, the cabin heater 404 may be coupled to the BD valve 116, for example, through the fourth port 208 of the BD valve 116. Accordingly, the heated coolant that reaches the BD valve 116 from the battery 102 after cooling the battery 102 through the third port 206 may be supplied to the cabin heater 404 through the fourth port 208. The coolant from which the thermal energy has been absorbed by the cabin heater 404 flows to the pump 110, for example, through the radiator 106. If the passenger cabin 402 is not to be heated, the coolant does not flow to the cabin heater 404, and directly flows from the BD valve 406 to the radiator 106. To allow flow of the coolant through the cabin heater 404, a valve 406 disposed between the BD valve 116 and the cabin heater 404 may be utilized. For a first position of the valve 406, the coolant may flow through the cabin heater 404 and for a second position of the valve 406, the coolant may bypass the cabin heater 404 and may flow directly to the radiator 106. The control of the position of the valve 406 may be performed by an HVAC control unit (not shown in Fig. 4).
[0048] The coolant flowing to the radiator 106 gets cooled and flows to the pump 110. The pump 110 pumps the coolant through the BD valve 116.
[0049] The utilization of the thermal energy derived from the heated coolant for heating the passenger cabin increases efficiency of the vehicle 400, as the cabin heater 404 need not generate heat for heating the passenger cabin. Further, parasitic losses in the vehicle 400 are reduced.
[0050] Fig. 5 illustrates a vehicle 500 in which temperature of a battery is to be controlled, according to an implementation of the present subject matter. The vehicle 500 may include a traction motor 502 that drives the vehicle 500. Accordingly, the vehicle 500 may be an EV. The traction motor 502 may be powered by a battery 504, which corresponds to the battery 102. The vehicle 500

may include a TMS 506 to control the temperature of the battery 502. The TMS 506 corresponds to the TMS 104.
[0051] The TMS 506 includes a BD valve 508, which corresponds to the BD valve 116. A position of the BD valve 508 determines a direction of flow of coolant through the battery 504. The position of the BD valve 508 may be controlled by a TCU 510, which corresponds to the TCU 118. The TCU 510 may be implemented, for example, as a microprocessor, a microcomputer, a microcontroller, a digital signal processor, a logic circuitry, and/or any device that manipulates signals based on operational instructions. Among other capabilities, the TCU 510 may fetch and execute computer-readable instructions included in a memory (not shown in Fig. 5). The functions of the TCU 510 may be provided through the use of dedicated hardware as well as hardware capable of executing machine-readable instructions.
[0052] The TCU 510 may monitor temperature of at least a part of the battery 504 and may control the position of the BD valve 508 based on the monitored temperature, to maintain a substantially uniform temperature distribution across the battery 504. For instance, the control may be based on temperature of a cell closest to a first end (not shown in Fig. 5) of the battery 504, temperature of a cell closest to a second end (not shown in Fig. 5) of the battery 504, temperature of a cell near a mid-point (a point equidistant from the first end and the second end) of the battery 504, or any combination thereof.
[0053] In addition to controlling the position of the BD valve 508, the TCU 510 may also control operation of a pump 512, which pumps the coolant. The pump 512 corresponds to the pump 110. The TCU 510 may control flow rate of the pump 512, for example, based on temperature of the coolant and a target temperature of the battery 504. The manner in which the TCU 510 may control the pump will be understood by a person skilled in the art, and is not explained herein for the sake of brevity.

[0054] Fig. 6 illustrates a method 600 for controlling temperature of a battery of a vehicle using a BD valve, according to an implementation of the present subject matter. It may be understood that steps of the method 600 may be performed by a programmed computing unit, such as the TCU 118, of the vehicle. The steps of the method 600 may be executed based on instructions stored in a non-transitory computer readable medium, as will be readily understood. The non-transitory computer readable medium may include, for example, digital memories.
[0055] The order in which the method 600 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method 600, or an alternative method. Additionally, individual blocks may be deleted from the method 600 without departing from the scope of the subject matter described herein. Furthermore, the method 600 can be implemented in any suitable hardware, non-transitory machine-readable instructions, or combination thereof. A person skilled in the art will readily recognize that steps of the method 600 can be performed by programmed computing devices. Herein, some examples are also intended to cover program storage devices, for example, digital data storage media, which are machine or computer-readable and encode machine-executable or computer-executable programs of instructions, wherein said instructions perform some or all of the steps of the described method. The program storage devices may be, for example, digital memories.
[0056] At block 602, temperature of at least a part of the battery is monitored. For example, temperature of a cell closest to a first end of the battery (also referred to as a first cell) and temperature of a cell closest to a second end of the battery (also referred to as a last cell) may be monitored. A coolant is to be flown between the first end and the second end of the battery to control the temperature of the battery, as explained earlier.

[0057] Subsequently, based on the monitored temperature, it is determined whether the coolant is to flow through the battery from the first end to the second end or from the second end to the first end. Based on the determination, the direction of flow of the coolant is controlled. For example, at block 604, it may be checked if difference between the temperature of the first cell and the temperature of the last cell is more than a threshold, such as 5° C. If no, it may be determined that the position of the BD valve may be maintained as it is, and the monitoring of temperatures at block 602 is continued. For example, if the difference in the temperatures is less than the threshold when the BD valve is in its first position (which causes the coolant to flow from the first end to the second end of the battery), it may be determined that the BD valve may be maintained in its first position. If the temperature difference is higher than the threshold, it may be determined that the position of the BD valve is to be changed. For example, if the BD valve is in its first position, it may be determined that the BD valve is to be changed to its second position.
[0058] Before changing the position of the BD valve, at block 606, a speed, i.e., a flow rate, of the pump may be reduced, to reduce flow rate of the coolant that flows through the battery. The flow rate may be reduced to prevent the occurrence of water hammer. The reduced flow rate may be maintained for a predetermined period, such as one second. Subsequently, at block 608, the position of the BD valve may be changed. Further, the monitoring of temperatures, at block 602, may be performed. The monitoring of temperatures may be carried out after elapse of a predetermined period, such as one minute, from the change of the position of the BD valve.
[0059] The present subject matter reduces the temperature differences between various regions in a battery of a vehicle, and enables achieving and maintaining a substantially uniform temperature across the battery. Thus, the temperature gradient within the battery can be maintained at a reduced level. The present subject matter can be implemented in batteries having various types of cells, such as cylindrical

cells, prismatic cells, and pouch cells. Also, techniques of the present subject matter can be applied even to already-manufactured vehicles by retrofitting. For instance, a vehicle currently in operation may be retrofitted with the BD valve and the control logic implemented in the temperature control unit of the vehicle may be modified to control the position of the BD valve.
[0060] The present subject matter can be utilized to achieve a quick heating and cooling of various regions of the battery as per requirement. The present subject matter can be achieved without modifying the coolant flow passages of a battery. Further, the present subject matter is agnostic to various types of coolants.
[0061] The techniques of the present subject matter can be utilized during various modes of operation of the battery. For example, the techniques can be used for a hot or a cold soak of the battery, when the battery is not operational and when the battery is to be brought to a required temperature in quick manner. The techniques can also be used during normal battery operation when the ambient temperature causes temperature of regions of the battery to breach a threshold. Further, the techniques can be used when a predicted rate of temperature change or an actual rate of temperature change exceeds a threshold.
[0062] The foregoing description of the specific implementations will so fully reveal the general nature of the implementations herein that others can, by applying current knowledge, readily modify and/or adapt for various applications without departing from the generic concept, and, therefore, such modifications and adaptations should and are intended to be comprehended within the meaning and range of equivalents of the disclosed implementations. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the implementations herein have been described in terms of preferred implementations, those skilled in the art will recognize that the implementations herein can be practiced with modification within the spirit and scope of the implementations as described herein.

We Claim:
1. A thermal management system (TMS) for a battery of a vehicle, the TMS
comprising:
a bi-directional (BD) valve to be coupled to a first end and to a second end of the battery and to allow flow of a coolant through the battery between the first end and the second end, wherein a first position of the BD valve allows the coolant to flow from the first end to the second end and wherein a second position of the BD valve allows the coolant to flow from the second end to the first end; and
a temperature control unit (TCU) to:
monitor temperature of at least a part of the battery; and
control position of the BD valve to the first position or the second
position based on the temperature, to maintain a substantially uniform
temperature distribution across the battery.
2. The TMS as claimed in claim 1, comprising:
a pump to pump the coolant though the BD valve; and
a radiator to receive the coolant from the battery through the BD valve, cool the coolant, and supply the cooled coolant to the pump.
3. The TMS as claimed in claim 2, wherein the BD valve comprises:
a first port through which the BD valve is to receive the coolant from the pump;
a second port through which the coolant is to flow between the BD valve and the first end of the battery;
a third port through which the coolant is to flow between the BD valve and the second end of the battery; and
a fourth port through which the coolant is flow from the BD valve to the radiator.

4. The TMS as claimed in claim 3, wherein the BD valve comprises a spool, wherein in the first position of the BD valve, the spool is positioned such that the coolant flows from the first port to the second port and from the third port to the fourth port, and wherein in the second position of the BD valve, the spool is positioned such that the coolant flows from the first port to the third port and from the second port to the fourth port.
5. The TMS as claimed in claim 1, comprising a hydraulic accumulator disposed between the BD valve and the battery.
6. The TMS as claimed in claim 1, wherein the temperature monitored by the TCU is a maximum temperature within the battery, an average temperature within the battery, or a temperature gradient within the battery.
7. The TMS as claimed in claim 1, and wherein the TCU is to:
monitor a first temperature of a first cell closer to the first end than to the second end and a second temperature of a last cell closer to the second end than to the first end;
determine a difference between the first temperature and the second temperature; and
change the position of the BD valve in response to the difference exceeding a threshold.
8. The TMS as claimed in claim 1, wherein the TCU is to:
monitor a rate of change of temperature of the battery; and control position of the BD valve to the first position or the second position based on the rate of change of temperature.
9. A vehicle comprising:
a traction motor to drive the vehicle;

a battery to power the traction motor, the battery comprising a first end and a second end, wherein a coolant is to flow through the battery between the first end and the second end to control temperature of the battery;
a bi-directional (BD) valve coupled to the first end and to the second end of the battery, to control flow of the coolant through the battery between the first end and the second end, wherein a first position of the BD valve allows the coolant to flow from the first end to the second end, and wherein the second position of the BD valve allows the coolant to flow from the second end to the first end; and
a temperature control unit (TCU) to:
monitor temperature of at least a part of the battery; and
control position of the BD valve to the first position or the second
position based on the temperature.
10. The vehicle as claimed in claim 9, comprising:
a cabin heater to heat a passenger cabin of the vehicle, wherein the BD valve is coupled to the cabin heater to supply the coolant that flowed through the battery to the cabin heater, to supply thermal energy from the coolant to the cabin heater; and
a pump to receive the coolant from the cabin heater and to pump the received coolant through the BD valve.
11. A method for controlling temperature of a battery of a vehicle, the method
performed by a temperature control unit (TCU) of the vehicle and comprising:
monitoring temperature of at least a part of the battery, wherein a coolant is to flow through the battery between a first end and a second end of the battery to control the temperature of the battery;
determining, based on the monitored temperature, whether the coolant is to flow through the battery from the first end to the second end or from the second end to the first end; and

controlling a direction of flow of the coolant based on the determination.
12. The method as claimed in claim 11, wherein the vehicle comprises a bi-directional valve coupled to the first end and to the second end of the battery, wherein the coolant is to flow to the battery through the BD valve, and wherein controlling the direction of flow of the coolant comprises controlling position of the BD valve.